/* ── ErrBits SystemC Studio Styles ── */
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    :root {
      --bg: #08090d; --bg-elevated: #0e1017; --surface: #13151d; --border: #1c1f2e;
      --border-hover: #2a2e42;
      --text: #e2e4ef; --text-muted: #7c7f96;
      --green: #22d97f; --green-dim: rgba(34,217,127,.12); --green-mid: rgba(34,217,127,.25);
      --red: #ff5f5f; --red-dim: rgba(255,95,95,.08); --red-border: rgba(255,95,95,.25);
      --amber: #f5a623; --blue: #5b9cf5; --cyan: #00d2d3;
      --mono: 'JetBrains Mono', monospace; --sans: 'Inter', -apple-system, sans-serif;
      --nav-w: 268px;
      --topbar-h: 52px;
    }

    html, body { height: 100%; overflow: hidden; }
    body { font-family: var(--sans); background: var(--bg); color: var(--text); line-height: 1.6; }

    /* ── Page shell ── */
    .studio-page {
      height: 100vh;
      display: flex;
      flex-direction: column;
      overflow: hidden;
    }

    /* ── Topbar ── */
    .studio-topbar {
      flex-shrink: 0;
      height: var(--topbar-h);
      display: flex;
      align-items: center;
      gap: .75rem;
      padding: 0 1rem;
      background: rgba(8,9,13,.94);
      border-bottom: 1px solid var(--border);
      backdrop-filter: blur(18px);
      z-index: 10;
    }
    .topbar-left { display: flex; align-items: center; gap: .6rem; flex-shrink: 0; }
    .topbar-center { flex: 1; display: flex; justify-content: center; }
    .topbar-right { display: flex; align-items: center; gap: .55rem; flex-shrink: 0; }

    .nav-toggle-btn {
      width: 30px; height: 30px; border-radius: 7px;
      border: 1px solid var(--border); background: var(--surface);
      color: var(--text-muted); font-size: .82rem; cursor: pointer;
      display: flex; align-items: center; justify-content: center;
      transition: border-color .2s, color .2s;
    }
    .nav-toggle-btn:hover { border-color: var(--green); color: var(--green); }

    .brand { font-family: var(--mono); font-size: .82rem; white-space: nowrap; }
    .brand .slash { color: #FF6B00; }
    .brand .name  { color: #ffffff; }
    .brand .muted { color: var(--text-muted); opacity: .5; }
    .brand .sep { color: var(--border); margin: 0 .4rem; }
    .brand .label { color: var(--text-muted); }

    .progress-crumb {
      font-family: var(--mono); font-size: .72rem;
      color: var(--text-muted);
      background: var(--surface); border: 1px solid var(--border);
      border-radius: 20px; padding: .25rem .75rem;
      white-space: nowrap;
    }
    .progress-crumb .crumb-track { color: var(--green); }
    .progress-crumb .crumb-step { color: var(--text); }

    .back-link {
      border: 1px solid var(--border); background: var(--surface); color: var(--text-muted);
      border-radius: 7px; padding: .35rem .65rem; font-size: .74rem; text-decoration: none;
      white-space: nowrap; transition: border-color .2s, color .2s;
    }
    .back-link:hover { border-color: var(--green); color: var(--text); }

    /* nav user dropdown */
    .nav-user-menu { position: relative; }
    .nav-user-btn { display: flex; align-items: center; gap: .45rem; background: none; border: none; cursor: pointer; color: var(--text); padding: .2rem 0; font-family: var(--sans); }
    .nav-user-avatar { width: 26px; height: 26px; border-radius: 50%; object-fit: cover; border: 2px solid var(--green); display: block; }
    .nav-user-initials { width: 26px; height: 26px; border-radius: 50%; background: var(--green); color: #080a0d; display: flex; align-items: center; justify-content: center; font-weight: 700; font-size: .7rem; flex-shrink: 0; }
    .nav-user-name { font-size: .76rem; font-weight: 600; color: var(--text); }
    .nav-user-drop { display: none; position: absolute; right: 0; top: calc(100% + 8px); background: var(--surface); border: 1px solid var(--border); border-radius: 10px; min-width: 210px; z-index: 200; box-shadow: 0 8px 24px rgba(0,0,0,.5); overflow: hidden; }
    .nav-user-drop.open { display: block; }
    .nav-drop-header { display: flex; align-items: center; gap: .75rem; padding: .85rem 1rem; }
    .nav-drop-header img, .nav-drop-header .nav-user-initials { width: 36px; height: 36px; border-radius: 50%; flex-shrink: 0; object-fit: cover; }
    .nav-drop-name { font-size: .85rem; font-weight: 600; color: var(--text); }
    .nav-drop-email { font-size: .7rem; color: var(--text-muted); margin-top: .1rem; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; max-width: 155px; }
    .nav-drop-divider { border: none; border-top: 1px solid var(--border); margin: 0; }
    .nav-drop-item { display: flex; align-items: center; gap: .55rem; width: 100%; padding: .6rem 1rem; background: none; border: none; cursor: pointer; color: var(--text-muted); font-size: .82rem; font-family: var(--sans); text-align: left; transition: background .15s, color .15s; }
    .nav-drop-item:hover { background: rgba(255,255,255,.04); color: var(--text); }
    .nav-drop-item svg { flex-shrink: 0; }
    .nav-drop-logout:hover { color: var(--red) !important; }

    /* ── Main workspace ── */
    .studio-wrap {
      flex: 1;
      min-height: 0;
      padding: .85rem;
      overflow: hidden;
      display: flex;
      flex-direction: column;
    }

    .studio-grid {
      flex: 1;
      min-height: 0;
      display: grid;
      grid-template-columns: var(--nav-w) 1fr;
      gap: .85rem;
      transition: grid-template-columns .28s cubic-bezier(.4,0,.2,1);
    }
    .studio-grid.nav-collapsed { grid-template-columns: 38px 1fr; }

    /* ── Panels ── */
    .panel {
      background: var(--bg-elevated);
      border: 1px solid var(--border);
      border-radius: 12px;
      overflow: hidden;
      display: flex;
      flex-direction: column;
      min-height: 0;
    }

    /* ── Nav / flow panel ── */
    .flow-panel { transition: none; }

    /* Normal state — show full content, hide strip */
    .flow-panel .panel-title-row  { display: flex; }
    .flow-panel .panel-inner       { display: flex; flex: 1; flex-direction: column; min-height: 0; }
    .flow-panel .panel-collapsed-strip { display: none; }

    /* Collapsed state — show strip, hide content */
    .studio-grid.nav-collapsed .flow-panel .panel-title-row  { display: none; }
    .studio-grid.nav-collapsed .flow-panel .panel-inner       { display: none; }
    .studio-grid.nav-collapsed .flow-panel .panel-collapsed-strip { display: flex; }

    /* ── Collapse / expand button in panel header ── */
    .panel-collapse-btn {
      margin-left: auto;
      background: none; border: none; cursor: pointer;
      color: var(--text-muted); padding: .25rem .35rem;
      border-radius: 5px; display: flex; align-items: center;
      transition: color .18s, background .18s;
      flex-shrink: 0;
    }
    .panel-collapse-btn:hover { color: var(--accent); background: rgba(99,102,241,.1); }

    /* ── Collapsed strip ── */
    .panel-collapsed-strip {
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: .75rem 0 1rem;
      height: 100%;
      cursor: pointer;
      border-right: 2px solid var(--green);
      gap: .5rem;
      transition: background .2s;
    }
    .panel-collapsed-strip:hover { background: rgba(34,217,127,.06); }
    .strip-expand-btn {
      background: none; border: none; cursor: pointer;
      color: var(--text-muted); padding: .3rem;
      border-radius: 5px; display: flex; align-items: center;
      transition: color .18s, background .18s;
      pointer-events: none;
    }
    .panel-collapsed-strip:hover .strip-expand-btn { color: var(--green); }
    .strip-label {
      writing-mode: vertical-rl;
      text-orientation: mixed;
      transform: rotate(180deg);
      font-size: .68rem; font-weight: 700; letter-spacing: .08em;
      color: var(--text-muted); text-transform: uppercase;
      user-select: none;
    }

    .panel-inner {
      flex: 1;
      overflow-y: auto;
      overflow-x: hidden;
      padding: .9rem;
      scrollbar-width: thin;
      scrollbar-color: var(--border) transparent;
    }
    .panel-inner::-webkit-scrollbar { width: 4px; }
    .panel-inner::-webkit-scrollbar-track { background: transparent; }
    .panel-inner::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }

    .panel-title-row {
      display: flex; align-items: center;
      padding: .75rem .9rem .5rem;
      border-bottom: 1px solid var(--border);
      flex-shrink: 0;
    }
    .panel-title {
      font-family: var(--mono); font-size: .68rem;
      color: var(--text-muted); text-transform: uppercase; letter-spacing: .4px;
      flex: 1;
    }

    /* ── Checkpoint list ── */
    .checkpoint-list, .step-sublist, .practice-list { list-style: none; }
    .checkpoint-list { display: flex; flex-direction: column; gap: .45rem; }

    .checkpoint-item { position: relative; padding-left: 1.4rem; }
    .checkpoint-item::before {
      content: ''; position: absolute; left: .42rem; top: 1.8rem; bottom: -.65rem;
      width: 1px; background: var(--border);
    }
    .checkpoint-item:last-child::before { display: none; }

    .checkpoint-btn {
      width: 100%; text-align: left;
      border: 1px solid var(--border); background: var(--surface); color: var(--text);
      border-radius: 8px; padding: .58rem .7rem; cursor: pointer;
      transition: border-color .18s, background .18s, transform .12s;
      font-size: .78rem; position: relative; font-family: var(--sans);
    }
    .checkpoint-btn::before {
      content: ''; position: absolute; left: -1rem; top: .84rem;
      width: 9px; height: 9px; border-radius: 50%;
      border: 1px solid var(--border); background: var(--bg);
    }
    .checkpoint-btn:hover:not(.locked) { border-color: var(--green); transform: translateX(2px); }
    .checkpoint-btn.active { border-color: rgba(34,217,127,.5); background: var(--green-dim); }
    .checkpoint-btn.active::before { background: var(--green); border-color: rgba(34,217,127,.7); box-shadow: 0 0 0 2px rgba(34,217,127,.18); }
    .checkpoint-btn.done::before { background: rgba(34,217,127,.45); border-color: rgba(34,217,127,.45); }
    .checkpoint-btn small { display: block; color: var(--text-muted); font-size: .7rem; margin-top: .18rem; line-height: 1.4; }
    .checkpoint-check { display: none; margin-left: .4rem; color: var(--green); font-family: var(--mono); font-size: .7rem; font-weight: 700; }
    .checkpoint-btn.done .checkpoint-check { display: inline-block; }
    .section-caret { float: right; color: var(--text-muted); font-size: .68rem; transition: transform .2s, color .2s; }
    .checkpoint-btn.active .section-caret { color: var(--green); }
    .checkpoint-btn.expanded .section-caret { transform: rotate(90deg); }
    .checkpoint-btn.locked { opacity: .55; cursor: not-allowed; border-style: dashed; }

    .locked-banner {
      display: flex; gap: .55rem; align-items: flex-start;
      padding: .65rem .7rem;
      border: 1px solid var(--red-border); background: var(--red-dim);
      border-radius: 7px; color: var(--text-muted);
      margin-bottom: .55rem; font-size: .77rem; line-height: 1.55;
    }
    .locked-banner b { color: var(--red); }

    .unlock-banner {
      margin: .5rem 0 .5rem 1.4rem;
      background: var(--green-dim); border: 1px solid rgba(34,217,127,.3);
      border-radius: 10px; padding: 1rem 1.1rem;
    }
    .unlock-top { display:flex; justify-content:space-between; align-items:center; margin-bottom:.4rem; }
    .unlock-check { font-size:.78rem; color:var(--green); font-weight:600; }
    .unlock-price { font-family:var(--mono); font-size:.85rem; color:var(--green); font-weight:700; }
    .unlock-desc { font-size:.75rem; color:var(--text-muted); line-height:1.5; margin-bottom:.75rem; }
    .btn-unlock {
      width:100%; padding:.55rem; border-radius:8px; border:none;
      background:var(--green); color:#080a0d;
      font-weight:700; font-size:.82rem; cursor:pointer;
      transition: background .2s;
    }
    .btn-unlock:hover { background:#1bc46e; }

    .step-sublist {
      margin: .3rem 0 .3rem 1.4rem; padding-left: .6rem;
      border-left: 1px dashed var(--border);
      display: flex; flex-direction: column; gap: .35rem;
    }
    .step-sublist .checkpoint-item { padding-left: 1.15rem; }
    .step-sublist .checkpoint-item::before { left: .22rem; top: 1.55rem; bottom: -.55rem; }
    .step-sublist .checkpoint-btn { font-size: .74rem; padding: .46rem .6rem; background: rgba(19,21,29,.65); }
    .step-sublist .checkpoint-btn::before { left: -.82rem; top: .66rem; width: 8px; height: 8px; }

    /* ── Context (right) panel ── */
    .context-panel {
      display: flex;
      flex-direction: column;
    }

    .context-head {
      padding: .45rem 1rem .4rem;
      border-bottom: 1px solid var(--border);
      flex-shrink: 0;
    }
    .context-head h3 { font-size: .82rem; font-weight: 600; margin-bottom: .1rem; line-height: 1.3; color: var(--text); }
    .context-head p { color: var(--text-muted); font-size: .72rem; line-height: 1.4; }

    .tabs-row {
      display: flex; gap: .4rem; align-items: center;
      padding: .6rem 1.1rem;
      border-bottom: 1px solid var(--border);
      flex-shrink: 0;
      background: rgba(8,9,13,.4);
    }
    .tab {
      border: 1px solid var(--border); background: transparent; color: var(--text-muted);
      font-size: .7rem; font-family: var(--mono); padding: .3rem .55rem;
      border-radius: 5px; cursor: pointer; transition: border-color .18s, color .18s, background .18s;
    }
    .tab.active { border-color: rgba(34,217,127,.5); color: var(--green); background: var(--green-dim); }
    .tab:hover:not(.active) { border-color: var(--border-hover); color: var(--text); }

    /* ── Context body (the big scrollable area) ── */
    .context-body {
      flex: 1;
      min-height: 0;
      overflow: hidden;
      position: relative;
    }
    .ctx {
      display: none;
      position: absolute; inset: 0;
      overflow-y: auto;
      padding: 1.1rem 1.3rem;
      scrollbar-width: thin;
      scrollbar-color: var(--border) transparent;
    }
    .ctx::-webkit-scrollbar { width: 5px; }
    .ctx::-webkit-scrollbar-track { background: transparent; }
    .ctx::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
    .ctx.active { display: block; }

    /* ── Article backlinks in theory ── */
    .studio-article-link {
      margin-top: 1.2rem; padding: .85rem 1.1rem;
      border: 1px solid rgba(34,217,127,.22);
      border-left: 3px solid #22d97f;
      border-radius: 8px; background: rgba(34,217,127,.04);
      display: flex; flex-direction: column; gap: .4rem;
    }
    .sal-label {
      font-size: .7rem; font-weight: 700; color: #22d97f;
      text-transform: uppercase; letter-spacing: .07em;
    }
    .sal-link {
      font-size: .85rem; font-weight: 600; color: var(--text);
      text-decoration: none; transition: color .2s;
    }
    .sal-link:hover { color: #22d97f; }

    /* ── Theory content typography ── */
    .ctx h4 {
      font-size: .88rem; font-weight: 700; color: var(--text);
      margin-bottom: .45rem; margin-top: 1.2rem;
    }
    .ctx h4:first-child { margin-top: 0; }
    .ctx p { color: var(--text-muted); font-size: .84rem; line-height: 1.7; margin-bottom: .65rem; }

    /* ── Theory images ── */
    .theory-img-wrap {
      margin: .85rem 0; border: 1px solid var(--border); border-radius: 7px; overflow: hidden;
      background: var(--bg-elevated); display: inline-block; max-width: 100%;
    }
    .theory-img-wrap img {
      display: block; max-width: 100%; max-height: 220px; width: auto; height: auto;
      filter: brightness(.9) contrast(1.06);
    }
    .theory-img-caption {
      padding: .28rem .65rem; font-family: var(--mono);
      font-size: .63rem; color: var(--text-muted);
      border-top: 1px solid var(--border); background: var(--bg-elevated);
    }
    .ctx p:last-child { margin-bottom: 0; }
    .ctx strong { color: var(--text); font-weight: 600; }
    .ctx code {
      font-family: var(--mono); font-size: .77rem;
      background: var(--bg); border: 1px solid var(--border);
      color: var(--cyan); border-radius: 4px; padding: .1rem .35rem;
    }
    .ctx ul { margin: .5rem 0 .65rem 0; display: flex; flex-direction: column; gap: .3rem; }
    .ctx li {
      color: var(--text-muted); font-size: .83rem;
      padding-left: 1rem; position: relative; line-height: 1.6;
    }
    .ctx li::before {
      content: '›'; position: absolute; left: 0;
      color: var(--green); font-family: var(--mono);
    }
    .ctx li code { font-size: .75rem; }

    /* ── Code block ── */
    .code-wrap {
      background: var(--bg); border: 1px solid var(--border);
      border-radius: 8px; overflow: hidden; margin-bottom: .65rem;
    }
    .code-header {
      display: flex; align-items: center; justify-content: space-between;
      padding: .45rem .75rem; border-bottom: 1px solid var(--border);
      background: rgba(255,255,255,.02);
    }
    .code-lang {
      font-family: var(--mono); font-size: .67rem;
      color: var(--text-muted); text-transform: uppercase; letter-spacing: .3px;
    }
    .code-dots { display: flex; gap: .35rem; }
    .code-dots span {
      width: 9px; height: 9px; border-radius: 50%;
    }
    .code-dots .d-red { background: #ff5f57; }
    .code-dots .d-amber { background: #febc2e; }
    .code-dots .d-green { background: #28c840; }
    pre {
      margin: 0; padding: .85rem 1rem;
      font-family: var(--mono); font-size: .76rem;
      line-height: 1.65; color: #c5cae0;
      overflow-x: auto; white-space: pre;
    }
    pre::-webkit-scrollbar { height: 4px; }
    pre::-webkit-scrollbar-track { background: transparent; }
    pre::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }

    /* ── Practice items ── */
    .practice-list { display: flex; flex-direction: column; gap: .5rem; }

    .practice-item { border: 1px solid var(--border); border-radius: 9px; overflow: hidden; transition: border-color .18s; }
    .practice-item.expanded { border-color: rgba(34,217,127,.35); }
    .practice-item-header { display: flex; align-items: flex-start; gap: .65rem; padding: .72rem .88rem; cursor: pointer; transition: background .15s; user-select: none; }
    .practice-item-header:hover { background: rgba(255,255,255,.025); }
    .practice-item.expanded .practice-item-header { background: rgba(34,217,127,.05); border-bottom: 1px solid rgba(34,217,127,.18); }
    .practice-num { font-family: var(--mono); font-size: .7rem; color: var(--green); font-weight: 700; flex-shrink: 0; margin-top: .18rem; }
    .practice-q { font-size: .82rem; color: var(--text); line-height: 1.6; flex: 1; }
    .practice-toggle { color: var(--text-muted); font-size: .6rem; flex-shrink: 0; margin-top: .22rem; transition: transform .2s, color .2s; }
    .practice-item.expanded .practice-toggle { transform: rotate(90deg); color: var(--green); }
    .practice-item-body { display: none; padding: .75rem .88rem .85rem; }
    .practice-item.expanded .practice-item-body { display: block; }

    .practice-editor-label { font-family: var(--mono); font-size: .67rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: .3px; margin-bottom: .4rem; }
    .practice-textarea {
      width: 100%; min-height: 110px;
      background: var(--bg); border: 1px solid var(--border); border-radius: 7px;
      padding: .65rem .8rem; font-family: var(--mono); font-size: .76rem;
      color: var(--text); resize: vertical; outline: none;
      line-height: 1.65; transition: border-color .2s;
    }
    .practice-textarea:focus { border-color: rgba(34,217,127,.45); }
    .practice-textarea::placeholder { color: var(--text-muted); opacity: .5; }

    .practice-actions { display: flex; gap: .5rem; margin-top: .55rem; flex-wrap: wrap; }
    .btn-check { display: flex; align-items: center; gap: .35rem; padding: .38rem .8rem; border-radius: 6px; border: 1px solid rgba(34,217,127,.4); background: var(--green-dim); color: var(--green); font-size: .74rem; font-family: var(--sans); cursor: pointer; transition: background .18s; }
    .btn-check:hover:not(:disabled) { background: var(--green-mid); }
    .btn-check:disabled { opacity: .4; cursor: not-allowed; }
    .btn-show { display: flex; align-items: center; gap: .35rem; padding: .38rem .8rem; border-radius: 6px; border: 1px solid var(--border); background: var(--surface); color: var(--text-muted); font-size: .74rem; font-family: var(--sans); cursor: pointer; transition: border-color .18s, color .18s; }
    .btn-show:hover:not(:disabled) { border-color: var(--amber); color: var(--amber); }
    .btn-show:disabled { opacity: .4; cursor: not-allowed; }

    .feedback-box { display: none; margin-top: .65rem; padding: .7rem .85rem; border-radius: 8px; font-size: .8rem; line-height: 1.7; }
    .feedback-box.is-loading { display: flex; align-items: center; gap: .6rem; border: 1px solid var(--border); background: var(--surface); color: var(--text-muted); }
    .feedback-box.is-check { display: block; border: 1px solid rgba(34,217,127,.22); background: rgba(34,217,127,.05); color: var(--text); }
    .feedback-box.is-show { display: block; border: 1px solid rgba(91,156,245,.22); background: rgba(91,156,245,.05); color: var(--text); }
    .feedback-box.is-error { display: block; border: 1px solid var(--red-border); background: var(--red-dim); color: #ff8a8a; }
    .feedback-tag { font-family: var(--mono); font-size: .67rem; font-weight: 700; text-transform: uppercase; letter-spacing: .3px; margin-bottom: .4rem; opacity: .75; }
    .feedback-box.is-check .feedback-tag { color: var(--green); }
    .feedback-box.is-show .feedback-tag { color: var(--blue); }
    .feedback-body code { font-family: var(--mono); font-size: .74rem; background: var(--bg); border: 1px solid var(--border); border-radius: 3px; padding: .08rem .3rem; color: var(--cyan); }
    .feedback-body strong { color: var(--text); font-weight: 600; }
    @keyframes spin { to { transform: rotate(360deg); } }
    .spinner { width: 13px; height: 13px; border-radius: 50%; border: 2px solid var(--border); border-top-color: var(--green); animation: spin .7s linear infinite; flex-shrink: 0; }

    /* API key bar */
    .api-key-bar { display: flex; align-items: center; gap: .5rem; flex-wrap: wrap; margin-bottom: .8rem; padding: .5rem .75rem; background: var(--surface); border: 1px solid var(--border); border-radius: 8px; }
    .api-key-bar.key-set { border-color: rgba(34,217,127,.3); }
    .api-key-label { font-family: var(--mono); font-size: .69rem; color: var(--text-muted); flex-shrink: 0; }
    .api-key-input { flex: 1; min-width: 120px; background: var(--bg); border: 1px solid var(--border); border-radius: 5px; padding: .28rem .55rem; font-family: var(--mono); font-size: .72rem; color: var(--text); outline: none; transition: border-color .2s; }
    .api-key-input:focus { border-color: rgba(34,217,127,.4); }
    .api-key-save { padding: .28rem .65rem; border-radius: 5px; flex-shrink: 0; border: 1px solid rgba(34,217,127,.4); background: var(--green-dim); color: var(--green); font-size: .72rem; font-family: var(--sans); cursor: pointer; }
    .api-key-status { font-size: .72rem; flex-shrink: 0; }

    /* ── Step nav footer ── */
    .step-nav {
      flex-shrink: 0;
      display: flex; align-items: center; justify-content: space-between;
      padding: .65rem 1.1rem;
      border-top: 1px solid var(--border);
      gap: .6rem;
    }
    .btn-step {
      display: flex; align-items: center; gap: .4rem;
      padding: .42rem .85rem; border-radius: 7px;
      border: 1px solid var(--border); background: var(--surface);
      color: var(--text-muted); font-size: .75rem; font-family: var(--sans);
      cursor: pointer; transition: border-color .18s, color .18s, background .18s;
    }
    .btn-step:hover:not(:disabled) { border-color: var(--green); color: var(--text); }
    .btn-step:disabled { opacity: .3; cursor: not-allowed; }
    .btn-step-next {
      background: var(--green-dim); border-color: rgba(34,217,127,.4); color: var(--green);
    }
    .btn-step-next:hover:not(:disabled) { background: var(--green-mid); }

    .step-position {
      font-family: var(--mono); font-size: .72rem; color: var(--text-muted);
    }
    .step-position b { color: var(--text); }

    /* ── Responsive ── */
    @media (max-width: 960px) {
      .studio-grid { grid-template-columns: 1fr !important; }
      .studio-grid.nav-collapsed { grid-template-columns: 1fr !important; }
      .flow-panel { max-height: 240px; }
      .flow-panel .panel-title-row  { display: flex !important; }
      .flow-panel .panel-inner       { display: flex !important; }
      .flow-panel .panel-collapsed-strip { display: none !important; }
      .panel-collapse-btn { display: none; }
      .progress-crumb { display: none; }
    }
    @media (max-width: 680px) {
      .nav-user-name { display: none; }
      .brand .label { display: none; }
    }

    /* ── Progress bar strip ── */
    .studio-progress-strip {
      flex-shrink: 0;
      display: flex; align-items: center; gap: .8rem;
      padding: .38rem 1.1rem;
      background: rgba(8,9,13,.7);
      border-bottom: 1px solid var(--border);
    }
    .spb-label {
      font-family: var(--mono); font-size: .69rem;
      color: var(--text-muted); white-space: nowrap;
    }
    .spb-label b { color: var(--green); }
    .spb-track {
      flex: 1; height: 5px;
      background: var(--border); border-radius: 3px; overflow: hidden;
    }
    .spb-fill {
      height: 100%;
      background: linear-gradient(90deg, #22d97f, #00d2d3);
      border-radius: 3px;
      transition: width .5s ease;
      width: 0%;
    }
    .spb-pct {
      font-family: var(--mono); font-size: .68rem;
      color: var(--text-muted); white-space: nowrap; min-width: 2.8rem; text-align: right;
    }
    /* ── Mark Done button ── */
    .btn-mark-done {
      display: flex; align-items: center; gap: .35rem;
      padding: .42rem .85rem; border-radius: 7px;
      border: 1px solid var(--border); background: var(--surface);
      color: var(--text-muted); font-size: .75rem; font-family: var(--sans);
      cursor: pointer; transition: border-color .2s, color .2s, background .2s;
    }
    .btn-mark-done:hover:not(:disabled) { border-color: rgba(34,217,127,.5); color: var(--green); }
    .btn-mark-done.is-done {
      border-color: rgba(34,217,127,.5); background: var(--green-dim); color: var(--green);
    }
    .btn-mark-done:disabled { opacity: .35; cursor: not-allowed; }
    @keyframes donePulse {
      0%   { box-shadow: 0 0 0 0 rgba(34,217,127,.5); }
      70%  { box-shadow: 0 0 0 7px rgba(34,217,127,0); }
      100% { box-shadow: 0 0 0 0 rgba(34,217,127,0); }
    }
    .btn-mark-done.pulse { animation: donePulse .5s ease; }

    /* ── Google Translate ── */
    .goog-te-banner-frame, .goog-te-gadget, #goog-gt-tt, .goog-tooltip { display: none !important; }
    body { top: 0 !important; }
    .goog-text-highlight { background: none !important; box-shadow: none !important; }

    .translate-wrap { position: relative; }
    .translate-btn {
      background: none; border: 1px solid var(--border);
      border-radius: 8px; padding: 5px 9px;
      cursor: pointer; color: var(--text-muted);
      transition: border-color .2s, color .2s;
      display: flex; align-items: center;
    }
    .translate-btn:hover { border-color: var(--green); color: var(--text); }
    .translate-drop {
      display: none; position: absolute; top: calc(100% + 8px); right: 0;
      background: var(--surface); border: 1px solid var(--border);
      border-radius: 10px; min-width: 170px;
      box-shadow: 0 12px 40px rgba(0,0,0,.5);
      overflow: hidden; z-index: 300; padding: .3rem 0;
    }
    .translate-drop.open { display: block; }
    .translate-opt {
      display: flex; align-items: center; gap: .6rem;
      padding: .5rem 1rem; width: 100%; text-align: left;
      background: none; border: none;
      font-size: .82rem; font-family: var(--sans); color: var(--text-muted);
      cursor: pointer; transition: background .15s, color .15s;
    }
    .translate-opt:hover { background: var(--border); color: var(--text); }
    .translate-opt.active { color: var(--green); }

    /* ── Login gate overlay ── */
    .studio-gate {
      display: none;
      position: fixed; inset: 0; z-index: 9999;
      background: var(--bg);
      overflow-y: auto;
    }
    .studio-gate.visible { display: block; }
    .gate-inner {
      max-width: 680px; margin: 0 auto;
      padding: 3.5rem 1.5rem 5rem;
      display: flex; flex-direction: column; align-items: center;
      text-align: center;
    }
    .gate-brand {
      font-family: var(--mono); font-size: .78rem;
      color: var(--text-muted); margin-bottom: 1.5rem;
      letter-spacing: .05em;
    }
    .gate-brand .slash { color: #FF6B00; }
    .gate-brand .name  { color: #ffffff; }
    .gate-h1 {
      font-size: 2.2rem; font-weight: 800; line-height: 1.2;
      margin-bottom: .75rem;
    }
    .gate-h1 span { color: var(--green); }
    .gate-sub {
      font-size: 1rem; color: var(--text-muted); line-height: 1.7;
      max-width: 520px; margin-bottom: 2rem;
    }
    .gate-features {
      display: flex; gap: .6rem; flex-wrap: wrap; justify-content: center;
      margin-bottom: 2rem;
    }
    .gate-feat {
      font-family: var(--mono); font-size: .72rem;
      border: 1px solid var(--border); border-radius: 20px;
      padding: .3rem .75rem; color: var(--text-muted);
    }
    .btn-gate-signin {
      display: flex; align-items: center; gap: .75rem;
      padding: .8rem 1.75rem; border-radius: 10px;
      background: var(--green-dim); border: 1px solid rgba(34,217,127,.4);
      color: var(--green); font-size: .95rem; font-weight: 700;
      font-family: var(--sans); cursor: pointer;
      transition: background .2s; margin-bottom: 2.5rem;
    }
    .btn-gate-signin:hover { background: var(--green-mid); }
    .gate-signin-wrap { display: flex; flex-direction: column; align-items: flex-start; gap: .75rem; margin-bottom: 2.5rem; }
    .btn-gate-signin-ms {
      display: flex; align-items: center; gap: .75rem;
      padding: .8rem 1.75rem; border-radius: 10px;
      background: rgba(0,164,239,.08); border: 1px solid rgba(0,164,239,.35);
      color: #00a4ef; font-size: .95rem; font-weight: 700;
      font-family: var(--sans); cursor: pointer; transition: background .2s;
    }
    .btn-gate-signin-ms:hover { background: rgba(0,164,239,.15); }
    .btn-gate-signin-gh {
      display: flex; align-items: center; gap: .75rem;
      padding: .8rem 1.75rem; border-radius: 10px;
      background: rgba(255,255,255,.06); border: 1px solid rgba(255,255,255,.18);
      color: var(--text); font-size: .95rem; font-weight: 700;
      font-family: var(--sans); cursor: pointer; transition: background .2s;
    }
    .btn-gate-signin-gh:hover { background: rgba(255,255,255,.12); }
    .gate-curriculum {
      width: 100%; text-align: left;
      border: 1px solid var(--border); border-radius: 12px;
      overflow: hidden; margin-bottom: 1.5rem;
    }
    .gate-curr-head {
      padding: .75rem 1.1rem;
      background: var(--surface); border-bottom: 1px solid var(--border);
      font-family: var(--mono); font-size: .72rem; font-weight: 700;
      text-transform: uppercase; letter-spacing: .06em; color: var(--text-muted);
    }
    .gate-curr-list { list-style: none; }
    .gate-curr-list li {
      display: flex; align-items: baseline; gap: .75rem;
      padding: .6rem 1.1rem; border-top: 1px solid var(--border);
      font-size: .85rem; color: var(--text-muted);
    }
    .gate-curr-list li:first-child { border-top: none; }
    .gate-curr-list li .step-num {
      font-family: var(--mono); font-size: .7rem;
      color: var(--green); flex-shrink: 0; min-width: 2rem;
    }
    .gate-curr-list li .step-name { color: var(--text); }
    .gate-curr-list li .step-sum { color: var(--text-muted); font-size: .78rem; }
    .gate-note {
      font-size: .78rem; color: var(--text-muted);
    }
    .gate-note a { color: var(--text-muted); text-decoration: underline; }
    .gate-curr-locked {
      display: flex; align-items: center; gap: .45rem;
      padding: .35rem .6rem; margin: .2rem 0 .6rem;
      font-size: .72rem; color: var(--text-muted); font-style: italic;
      border-left: 2px solid var(--border);
      background: rgba(255,255,255,.02); border-radius: 0 4px 4px 0;
    }
    .gate-curr-locked span { font-style: normal; font-size: .78rem; }

    /* ── Gate community card ── */
    .gate-community {
      width: 100%; margin: 2rem 0 1.5rem;
      background: var(--surface);
      border: 1px solid rgba(34,217,127,.22);
      border-radius: 12px;
      padding: 1.5rem 1.6rem;
      text-align: left;
      position: relative; overflow: hidden;
    }
    .gate-community::before {
      content: '';
      position: absolute; top: 0; left: 0;
      width: 3px; height: 100%;
      background: var(--green);
      border-radius: 12px 0 0 12px;
    }
    .gate-comm-tag {
      font-family: var(--mono); font-size: .68rem; font-weight: 600;
      color: var(--green); letter-spacing: .08em;
      background: rgba(34,217,127,.1); border: 1px solid rgba(34,217,127,.25);
      border-radius: 4px; padding: .18rem .5rem;
      display: inline-block; margin-bottom: .75rem;
    }
    .gate-community h3 {
      font-size: 1.05rem; font-weight: 700; color: var(--text);
      margin-bottom: .4rem; line-height: 1.35;
    }
    .gate-community h3 span { color: var(--green); }
    .gate-community > p {
      font-size: .82rem; color: var(--text-muted);
      line-height: 1.6; margin-bottom: 1rem;
    }
    .gate-comm-perks {
      display: flex; flex-direction: column; gap: .45rem;
    }
    .gate-comm-perk {
      display: flex; align-items: flex-start; gap: .55rem;
      font-size: .8rem; color: var(--text-muted);
    }
    .gate-comm-perk-dot {
      flex-shrink: 0; margin-top: .35em;
      width: 6px; height: 6px; border-radius: 50%;
      background: var(--green);
    }
    .gate-comm-perk strong { color: var(--text); }

    /* ── Gate studio preview snapshot ── */
    .gate-preview {
      margin: 1.75rem 0 0;
      border: 1px solid var(--border);
      border-radius: 12px;
      overflow: hidden;
      background: var(--bg-elevated);
      position: relative;
    }
    .gate-preview-label {
      padding: .42rem .85rem;
      font-size: .66rem; font-weight: 700; letter-spacing: .07em;
      text-transform: uppercase; color: var(--text-muted);
      border-bottom: 1px solid var(--border);
      background: rgba(255,255,255,.02);
    }
    .gate-preview-ui {
      display: grid;
      grid-template-columns: 168px 1fr 38px;
      height: 210px;
      position: relative;
    }
    .gprev-nav {
      border-right: 1px solid var(--border);
      overflow: hidden;
      padding: .45rem 0;
      background: var(--surface);
    }
    .gprev-nav-head {
      font-size: .6rem; font-weight: 700; letter-spacing: .08em;
      text-transform: uppercase; color: var(--text-muted);
      padding: 0 .65rem .4rem;
    }
    .gprev-step {
      display: flex; align-items: center; gap: .4rem;
      padding: .28rem .65rem; font-size: .7rem; color: var(--text-muted);
    }
    .gprev-step.done { color: var(--green); }
    .gprev-step.active {
      color: var(--text); background: rgba(34,217,127,.09);
      border-left: 2px solid var(--green); padding-left: calc(.65rem - 2px);
    }
    .gprev-step.locked { opacity: .55; }
    .gprev-check { font-size: .72rem; flex-shrink: 0; color: var(--green); }
    .gprev-dot {
      width: 6px; height: 6px; border-radius: 50%;
      background: var(--green); flex-shrink: 0;
    }
    .gprev-lock { font-size: .62rem; flex-shrink: 0; }
    .gprev-step-name { flex: 1; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
    .gprev-content { display: flex; flex-direction: column; overflow: hidden; }
    .gprev-tabs {
      display: flex; border-bottom: 1px solid var(--border); padding: 0 .5rem; flex-shrink: 0;
    }
    .gprev-tab {
      padding: .38rem .55rem; font-size: .68rem; font-weight: 600;
      color: var(--text-muted); cursor: default; user-select: none;
    }
    .gprev-tab.active { color: var(--accent); border-bottom: 2px solid var(--accent); }
    .gprev-code-wrap { flex: 1; overflow: hidden; }
    .gprev-code-header {
      display: flex; align-items: center; gap: .4rem;
      padding: .28rem .6rem; border-bottom: 1px solid var(--border);
      background: rgba(0,0,0,.25); font-size: .63rem; color: var(--text-muted);
    }
    .gprev-dots { display: flex; gap: .22rem; }
    .gprev-dots span { width: 7px; height: 7px; border-radius: 50%; }
    .gprev-d-r { background: #ff5f57; }
    .gprev-d-a { background: #ffbd2e; }
    .gprev-d-g { background: #28c840; }
    .gprev-code-pre {
      margin: 0; padding: .5rem .7rem;
      font-family: var(--mono); font-size: .66rem; line-height: 1.52;
      color: var(--text); background: transparent; overflow: hidden;
    }
    .gate-preview-fade {
      position: absolute; bottom: 0; left: 0; right: 0; height: 100px;
      background: linear-gradient(to bottom, transparent 0%, rgba(18,18,24,.97) 75%);
      display: flex; align-items: flex-end; justify-content: center;
      padding-bottom: .9rem; pointer-events: none;
    }
    .gate-preview-fade button { pointer-events: all; }
    .btn-gprev-cta {
      background: var(--green); color: #000;
      border: none; border-radius: 8px;
      padding: .42rem 1.25rem; font-size: .78rem; font-weight: 700;
      cursor: pointer; letter-spacing: .02em;
      transition: background .18s, transform .12s;
    }
    .btn-gprev-cta:hover { background: var(--green-mid); transform: translateY(-1px); }
    .gprev-disc-strip {
      display: flex; flex-direction: column;
      align-items: center; justify-content: center;
      gap: .5rem; padding: .5rem 0;
      border-left: 2px solid var(--green);
      background: var(--bg-elevated);
      cursor: default;
    }
    .gprev-disc-label {
      writing-mode: vertical-rl; text-orientation: mixed;
      transform: rotate(180deg);
      font-size: .65rem; color: var(--text-muted);
      font-family: var(--mono); letter-spacing: .08em; user-select: none;
    }
    .gprev-disc-dot {
      width: 7px; height: 7px; border-radius: 50%;
      background: var(--green);
      animation: disc-pulse 1.8s ease-in-out infinite;
    }
    @media (max-width: 520px) {
      .gate-preview-ui { grid-template-columns: 120px 1fr 32px; height: 195px; }
      .gprev-step-name { font-size: .65rem; }
    }

    /* ── Discussion Panel (right drawer) ── */
    :root { --disc-w: 320px; --disc-strip-w: 38px; }

    .disc-panel {
      position: fixed; right: 0; top: var(--topbar-h, 52px); bottom: 0;
      width: var(--disc-strip-w);
      background: var(--bg-elevated);
      border-left: 1px solid var(--border);
      z-index: 200; display: flex; flex-direction: row;
      transition: width .28s cubic-bezier(.4,0,.2,1);
      overflow: hidden;
    }
    .disc-panel.disc-open { width: var(--disc-w); }

    /* vertical handle strip */
    .disc-strip {
      width: var(--disc-strip-w); flex-shrink: 0;
      display: flex; flex-direction: column;
      align-items: center; justify-content: center;
      cursor: pointer; gap: .5rem; padding: .5rem 0;
      border-left: 2px solid var(--green);
      transition: background .2s;
    }
    .disc-strip:hover { background: rgba(34,217,127,.06); }
    .disc-strip-label {
      writing-mode: vertical-rl; text-orientation: mixed;
      transform: rotate(180deg);
      font-size: .7rem; color: var(--text-muted);
      font-family: 'JetBrains Mono', monospace;
      letter-spacing: .08em; user-select: none;
    }
    .disc-strip-dot {
      width: 7px; height: 7px; border-radius: 50%;
      background: var(--green); display: none;
    }
    .disc-strip-dot.active {
      display: block;
      animation: disc-pulse 1.8s ease-in-out infinite;
    }
    @keyframes disc-pulse {
      0%,100% { opacity:1; transform:scale(1); }
      50% { opacity:.4; transform:scale(.75); }
    }

    /* expanded content */
    .disc-content {
      flex: 1; min-width: 0; display: flex;
      flex-direction: column; overflow: hidden;
    }
    .disc-header {
      display: flex; align-items: center;
      justify-content: space-between;
      padding: .85rem 1rem .6rem;
      border-bottom: 1px solid var(--border);
      flex-shrink: 0;
    }
    .disc-title {
      font-family: 'JetBrains Mono', monospace;
      font-size: .82rem; color: var(--green); font-weight: 600;
    }
    .disc-close {
      background: none; border: none; color: var(--text-muted);
      cursor: pointer; font-size: .95rem;
      padding: .2rem .4rem; border-radius: 4px; line-height: 1;
    }
    .disc-close:hover { color: var(--text); background: var(--surface); }
    .disc-track-name {
      padding: .35rem 1rem; font-size: .7rem;
      color: var(--text-muted); font-family: 'JetBrains Mono', monospace;
      border-bottom: 1px solid var(--border); flex-shrink: 0;
    }

    /* notice bar */
    .disc-notice {
      display: flex; align-items: flex-start; gap: .4rem;
      padding: .45rem .9rem;
      background: rgba(34,217,127,.07);
      border-bottom: 1px solid rgba(34,217,127,.18);
      font-size: .7rem; color: var(--text-muted); line-height: 1.5;
      flex-shrink: 0;
    }
    .disc-notice strong { color: var(--green); font-weight: 600; }
    .disc-notice-icon { flex-shrink: 0; font-size: .78rem; margin-top: .05rem; }

    /* compose */
    .disc-compose {
      padding: .7rem 1rem;
      border-bottom: 1px solid var(--border); flex-shrink: 0;
    }
    .disc-compose textarea {
      width: 100%; box-sizing: border-box;
      background: var(--surface); border: 1px solid var(--border);
      border-radius: 6px; color: var(--text);
      font-family: 'Inter', sans-serif; font-size: .79rem;
      padding: .55rem .7rem; resize: none; height: 68px;
      outline: none; transition: border-color .2s;
    }
    .disc-compose textarea:focus { border-color: var(--green); }
    .disc-compose textarea::placeholder { color: var(--text-muted); }
    .disc-compose-footer {
      display: flex; justify-content: space-between;
      align-items: center; margin-top: .35rem;
    }
    .disc-char-count {
      font-size: .68rem; color: var(--text-muted);
      font-family: 'JetBrains Mono', monospace;
    }
    .disc-post-btn {
      background: var(--green); color: #080a0d;
      border: none; border-radius: 5px;
      padding: .3rem .9rem; font-size: .77rem;
      font-weight: 700; cursor: pointer; transition: background .2s;
    }
    .disc-post-btn:hover { background: #1bc46e; }
    .disc-post-btn:disabled { opacity: .5; cursor: not-allowed; }

    /* comments list */
    .disc-comments {
      flex: 1; overflow-y: auto; padding: .4rem 0;
      scrollbar-width: thin; scrollbar-color: var(--border) transparent;
    }
    .disc-comment {
      padding: .6rem 1rem; display: flex;
      gap: .55rem; align-items: flex-start;
    }
    .disc-comment:hover { background: rgba(255,255,255,.02); }
    .disc-avatar {
      width: 26px; height: 26px; border-radius: 50%;
      background: var(--green); color: #080a0d;
      font-size: .7rem; font-weight: 700;
      display: flex; align-items: center; justify-content: center;
      flex-shrink: 0; font-family: 'Inter', sans-serif;
    }
    .disc-comment-body { flex: 1; min-width: 0; }
    .disc-comment-meta {
      display: flex; align-items: center;
      gap: .35rem; margin-bottom: .18rem;
    }
    .disc-comment-name {
      font-size: .74rem; font-weight: 600; color: var(--text);
      white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
    }
    .disc-comment-time {
      font-size: .67rem; color: var(--text-muted);
      font-family: 'JetBrains Mono', monospace; flex-shrink: 0;
    }
    .disc-comment-text {
      font-size: .78rem; color: var(--text);
      line-height: 1.55; word-break: break-word; white-space: pre-wrap;
    }
    .disc-delete-btn {
      background: none; border: none; color: var(--text-muted);
      cursor: pointer; font-size: .68rem;
      padding: .1rem .3rem; border-radius: 3px;
      opacity: 0; transition: opacity .15s, color .15s; flex-shrink: 0;
    }
    .disc-comment:hover .disc-delete-btn { opacity: 1; }
    .disc-delete-btn:hover { color: #e55; }
    .disc-state {
      padding: 1.5rem 1rem; text-align: center;
      color: var(--text-muted); font-size: .79rem; line-height: 1.7;
    }
    @media (max-width: 600px) { .disc-panel { display: none; } }

/* ── Certificate Modal ── */
.cert-modal-overlay {
  position: fixed; inset: 0; z-index: 2000;
  background: rgba(0,0,0,.75); backdrop-filter: blur(6px);
  display: flex; align-items: center; justify-content: center;
  padding: 1.5rem;
}
.cert-modal {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 14px; width: 100%; max-width: 860px;
  max-height: 92vh; overflow-y: auto;
  box-shadow: 0 24px 80px rgba(0,0,0,.6);
}
.cert-modal-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 1rem 1.4rem; border-bottom: 1px solid var(--border);
}
.cert-modal-title {
  font-family: var(--mono); font-size: .88rem;
  color: var(--green); font-weight: 700; letter-spacing: .04em;
}
.cert-modal-close {
  background: none; border: none; color: var(--text-muted);
  font-size: 1rem; cursor: pointer; padding: .2rem .4rem;
  border-radius: 4px; transition: color .15s, background .15s;
}
.cert-modal-close:hover { color: var(--text); background: rgba(255,255,255,.06); }
.cert-preview-wrap {
  padding: 1.2rem 1.4rem .8rem;
}
.cert-preview-img {
  width: 100%; border-radius: 8px;
  border: 1px solid var(--border);
  box-shadow: 0 4px 20px rgba(0,0,0,.3);
}
.cert-modal-actions {
  display: flex; gap: .6rem; flex-wrap: wrap;
  padding: 0 1.4rem .8rem;
}
.cert-btn {
  display: inline-flex; align-items: center; gap: .45rem;
  padding: .48rem 1rem; border-radius: 7px;
  border: 1px solid var(--border); background: none;
  color: var(--text-muted); font-size: .8rem; font-weight: 600;
  cursor: pointer; text-decoration: none; font-family: var(--sans);
  transition: border-color .2s, color .2s, background .2s;
  white-space: nowrap;
}
.cert-btn:hover { border-color: var(--green); color: var(--green); background: rgba(34,217,127,.06); }
.cert-btn-primary {
  background: var(--green); color: #080a0d;
  border-color: var(--green);
}
.cert-btn-primary:hover { background: #1bc46e; border-color: #1bc46e; color: #080a0d; }
.cert-btn-li { border-color: rgba(0,119,181,.4); color: #0a66c2; }
.cert-btn-li:hover { border-color: #0a66c2; background: rgba(10,102,194,.07); color: #0a66c2; }
.cert-modal-id {
  padding: .5rem 1.4rem 1rem;
  font-size: .78rem; color: var(--text-muted); text-align: center;
}
.cert-modal-id code {
  font-family: var(--mono); color: var(--green); font-size: .8rem;
  background: rgba(34,217,127,.08); padding: .1rem .4rem; border-radius: 4px;
}

/* ── Print: show only certificate image ── */
@media print {
  body > *:not(#certModal) { display: none !important; }
  #certModal { position: static !important; background: white !important; padding: 0 !important; }
  .cert-modal { box-shadow: none !important; border: none !important; max-width: 100% !important; }
  .cert-modal-header, .cert-modal-actions, .cert-modal-id { display: none !important; }
  .cert-preview-img { width: 100% !important; border: none !important; }
}

/* ── Certificate view button in left nav ── */
.cert-view-btn {
  display: block; width: calc(100% - 1.4rem);
  margin: .25rem .7rem .4rem;
  padding: .35rem .7rem;
  background: rgba(34,217,127,.08);
  border: 1px solid rgba(34,217,127,.25);
  border-radius: 6px;
  color: var(--green); font-size: .73rem; font-weight: 600;
  font-family: var(--sans); cursor: pointer; text-align: left;
  transition: background .2s, border-color .2s;
}
.cert-view-btn:hover { background: rgba(34,217,127,.16); border-color: var(--green); }

    /* ── Task Checklist ── */
    .task-checklist { padding: .6rem 1rem .5rem; border-top: 1px solid var(--border); background: rgba(13,15,23,.5); }
    .task-cl-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: .5rem; }
    .task-cl-label { font-family: var(--mono); font-size: .68rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: .05em; }
    .task-cl-progress { font-family: var(--mono); font-size: .72rem; font-weight: 600; }
    .task-cl-items { display: flex; flex-direction: column; gap: .3rem; }
    .task-item { display: flex; align-items: flex-start; gap: .6rem; padding: .38rem .5rem; border-radius: 6px; transition: background .15s; }
    .task-item:hover { background: rgba(255,255,255,.03); }
    .task-item.done .task-label { color: var(--text-muted); text-decoration: line-through; opacity: .65; }
    .task-checkbox { width: 18px; height: 18px; min-width: 18px; border-radius: 4px; border: 1.5px solid var(--border); background: var(--surface); cursor: pointer; display: flex; align-items: center; justify-content: center; transition: border-color .15s, background .15s; padding: 0; flex-shrink: 0; margin-top: .1rem; }
    .task-item.done .task-checkbox { border-color: rgba(34,217,127,.5); background: rgba(34,217,127,.12); }
    .task-checkbox:hover { border-color: var(--green); }
    .task-label { font-size: .8rem; color: var(--text); line-height: 1.5; }
    .task-step-badge { font-family: var(--mono); font-size: .62rem; color: var(--amber); background: rgba(245,166,35,.12); border: 1px solid rgba(245,166,35,.25); border-radius: 3px; padding: .05rem .28rem; margin-left: .35rem; vertical-align: middle; }
    .btn-task-mark { display: inline-flex; align-items: center; gap: .35rem; margin-top: .75rem; padding: .38rem .85rem; border-radius: 6px; border: 1px solid var(--border); background: var(--surface); color: var(--text-muted); font-size: .78rem; font-family: var(--mono); cursor: not-allowed; opacity: .45; transition: border-color .15s, color .15s, background .15s, opacity .15s; }
    .btn-task-mark.is-done { border-color: rgba(34,217,127,.5); background: rgba(34,217,127,.08); color: var(--green); font-weight: 600; cursor: pointer; opacity: 1; }
    .btn-task-mark.is-done:hover { border-color: var(--green); }

    /* ── Feedback widget ── */
    .fb-pill {
      position: fixed; bottom: 4.8rem; right: 1.4rem; z-index: 1200;
      display: flex; align-items: center; gap: .45rem;
      padding: .55rem; border-radius: 50%;
      border: 1px solid rgba(34,217,127,.35); background: var(--surface);
      color: var(--text-muted); font-size: .78rem; font-family: var(--mono);
      cursor: pointer; transition: border-color .15s, color .15s, box-shadow .15s;
      box-shadow: 0 2px 12px rgba(0,0,0,.35);
    }
    .fb-pill:hover { border-color: var(--green); color: var(--green); box-shadow: 0 4px 18px rgba(34,217,127,.12); }
    .fb-pill svg { flex-shrink: 0; }

    .fb-panel {
      position: fixed; bottom: 8rem; right: 1.4rem; z-index: 1200;
      width: 310px; background: var(--bg); border: 1px solid var(--border);
      border-radius: 12px; box-shadow: 0 8px 32px rgba(0,0,0,.45);
      display: none; flex-direction: column; overflow: hidden;
      transform: translateY(8px); opacity: 0;
      transition: transform .2s ease, opacity .2s ease;
    }
    .fb-panel.is-open { display: flex; transform: translateY(0); opacity: 1; }
    .fb-head {
      display: flex; align-items: center; justify-content: space-between;
      padding: .7rem 1rem; border-bottom: 1px solid var(--border);
      font-family: var(--mono); font-size: .78rem; color: var(--green);
    }
    .fb-close {
      background: none; border: none; color: var(--text-muted); cursor: pointer;
      font-size: 1rem; line-height: 1; padding: 0; transition: color .15s;
    }
    .fb-close:hover { color: var(--text); }
    .fb-body { padding: .85rem 1rem; display: flex; flex-direction: column; gap: .7rem; }
    .fb-cats {
      display: flex; flex-wrap: wrap; gap: .4rem;
    }
    .fb-cat {
      padding: .25rem .65rem; border-radius: 99px; border: 1px solid var(--border);
      background: var(--surface); color: var(--text-muted); font-size: .72rem;
      font-family: var(--mono); cursor: pointer; transition: border-color .12s, color .12s, background .12s;
    }
    .fb-cat:hover { border-color: rgba(34,217,127,.4); color: var(--green); }
    .fb-cat.active { border-color: var(--green); background: rgba(34,217,127,.1); color: var(--green); }
    .fb-textarea {
      width: 100%; box-sizing: border-box; resize: vertical;
      min-height: 80px; max-height: 160px;
      background: var(--surface); border: 1px solid var(--border);
      border-radius: 6px; padding: .55rem .7rem;
      color: var(--text); font-size: .8rem; font-family: var(--mono);
      line-height: 1.5; outline: none; transition: border-color .15s;
    }
    .fb-textarea:focus { border-color: rgba(34,217,127,.4); }
    .fb-textarea::placeholder { color: var(--text-muted); }
    .fb-submit {
      width: 100%; padding: .48rem; border-radius: 6px;
      border: 1px solid rgba(34,217,127,.4); background: rgba(34,217,127,.08);
      color: var(--green); font-size: .8rem; font-family: var(--mono);
      font-weight: 600; cursor: pointer; transition: background .15s, border-color .15s;
    }
    .fb-submit:hover { background: rgba(34,217,127,.15); border-color: var(--green); }
    .fb-submit:disabled { opacity: .5; cursor: not-allowed; }
    .fb-ok { padding: .7rem 1rem 1rem; font-size: .8rem; color: var(--green); text-align: center; }
    .fb-ctx { font-size: .68rem; color: var(--text-muted); font-family: var(--mono); }