:root{--primary:#2563eb;--primary-dark:#1d4ed8;--accent:#2563eb;--surface:#ffffff;--surface-muted:#f4f6fb;--border:#e2e8f0;--text-main:#0f172a;--text-muted:#64748b;--shadow-soft:0 20px 45px rgba(15,23,42,0.08);}
.idark-lede{max-width:42rem;margin:0 0 1.25rem;font-size:1.05rem;line-height:1.65;color:var(--text-main);}
.idark-mistake-band{margin:0 0 1.5rem;padding:1rem 1.1rem;border-radius:14px;border:1px solid var(--border);background:linear-gradient(135deg,rgba(0,0,0,.06),transparent);box-shadow:var(--shadow-soft);}
.idark-mistake-band h2{margin:0 0 .5rem;font-size:1.15rem;font-weight:700;color:var(--text-main);}
.idark-mistake-band p{margin:0 0 .65rem;font-size:.95rem;line-height:1.55;color:var(--text-muted);}
.idark-mistake-band p:last-child{margin-bottom:0;}
.idark-privacy-strip{display:flex;flex-wrap:wrap;gap:.5rem .75rem;align-items:center;margin:0 0 1rem;padding:.55rem .85rem;font-size:.8125rem;border-radius:10px;background:var(--surface-muted);color:var(--text-muted);border:1px solid var(--border);}
.idark-privacy-strip span{font-weight:600;color:var(--text-main);}
.idark-workbench{display:grid;gap:1rem;margin:0 0 2.5rem;padding:1rem;border-radius:18px;border:1px solid var(--border);background:var(--surface);box-shadow:var(--shadow-soft);}
@media (min-width:768px){.idark-workbench:not(.idark-workbench--editing){grid-template-columns:minmax(0,1fr) minmax(0,1.15fr);grid-template-rows:auto auto 1fr;gap:1.1rem 1.25rem;padding:1.25rem 1.35rem;}.idark-workbench:not(.idark-workbench--editing) .idark-drop-slab{grid-column:1;grid-row:1 / -1;}.idark-workbench:not(.idark-workbench--editing) .idark-rail-block{grid-column:2;grid-row:1;}.idark-workbench:not(.idark-workbench--editing) .idark-action-row{grid-column:2;grid-row:2;}.idark-workbench:not(.idark-workbench--editing) .idark-preview-scroller{grid-column:2;grid-row:3;}.idark-workbench.idark-workbench--editing{padding:1.25rem 1.35rem;}}
.idark-workbench.idark-workbench--editing .idark-drop-slab{display:none;}
.idark-drop-slab{position:relative;min-height:140px;padding:1.35rem 1rem;border-radius:14px;border:2px dashed color-mix(in srgb,var(--primary) 35%,var(--border));background:color-mix(in srgb,var(--surface-muted) 88%,transparent);display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;gap:.5rem;cursor:pointer;transition:border-color .2s,background .2s;}
.idark-drop-slab:hover,.idark-drop-slab.idark-drop-slab--active{border-color:var(--primary);background:color-mix(in srgb,var(--primary) 6%,var(--surface-muted));}
.idark-drop-slab strong{font-size:1rem;color:var(--text-main);}
.idark-drop-slab span{font-size:.85rem;color:var(--text-muted);line-height:1.4;}
.idark-rail-block{display:flex;flex-direction:column;gap:.6rem;}
.idark-rail-head{display:flex;justify-content:space-between;align-items:baseline;gap:.75rem;}
.idark-rail-head label{font-size:.8rem;font-weight:700;letter-spacing:.04em;text-transform:uppercase;color:var(--text-muted);}
.idark-rail-value{font-variant-numeric:tabular-nums;font-weight:700;font-size:1.1rem;color:var(--primary);}
.idark-slider{width:100%;height:10px;border-radius:999px;appearance:none;background:linear-gradient(90deg,var(--border),color-mix(in srgb,var(--text-muted) 35%,var(--border)));outline:none;}
.idark-slider::-webkit-slider-thumb{appearance:none;width:26px;height:26px;border-radius:50%;background:var(--primary);border:3px solid var(--surface);box-shadow:0 2px 8px rgba(15,23,42,0.15);cursor:pointer;}
.idark-slider::-moz-range-thumb{width:26px;height:26px;border-radius:50%;background:var(--primary);border:3px solid var(--surface);cursor:pointer;}
.idark-action-row{display:flex;flex-wrap:wrap;gap:.6rem;}
.idark-btn{flex:1;min-width:8rem;padding:.7rem 1rem;font-size:.9rem;font-weight:600;border-radius:12px;border:1px solid var(--border);background:var(--surface-muted);color:var(--text-main);cursor:pointer;transition:background .15s,border-color .15s,opacity .15s;}
.idark-btn:hover{background:color-mix(in srgb,var(--primary) 12%,var(--surface-muted));}
.idark-btn--primary{border-color:color-mix(in srgb,var(--primary) 45%,var(--border));background:var(--primary);color:#fff;}
.idark-btn--primary:hover{filter:brightness(1.05);}
.idark-btn--ghost{background:transparent;border-style:dashed;color:var(--text-muted);}
.idark-btn--ghost:hover{background:var(--surface-muted);color:var(--text-main);}
.idark-btn:disabled{opacity:.45;cursor:not-allowed;}
.idark-preview-scroller{display:none;margin:0;padding:0;list-style:none;gap:.75rem;}
.idark-preview-scroller.idark-preview-scroller--visible{display:flex;flex-direction:row;flex-wrap:nowrap;align-items:stretch;}
.idark-preview-card{flex:1 1 50%;min-width:0;border-radius:14px;overflow:hidden;border:1px solid var(--border);background:var(--surface-muted);}
.idark-preview-card figcaption{padding:.45rem .65rem;font-size:.72rem;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:var(--text-muted);background:var(--surface);}
.idark-preview-card figure{display:flex;flex-direction:column;margin:0;min-height:0;}
.idark-preview-card canvas{display:block;width:100%;max-width:100%;height:auto;vertical-align:middle;max-height:min(52vh,420px);object-fit:contain;background:repeating-conic-gradient(#e8ecf4 0% 25%,#f1f5f9 0% 50%) 50% / 12px 12px;box-sizing:border-box;}
.idark-edu-grid{display:grid;gap:1.5rem;margin:0 0 2.25rem;}
@media (min-width:900px){.idark-edu-grid{grid-template-columns:1fr 280px;align-items:start;}}
.idark-edu-main{display:flex;flex-direction:column;gap:1.75rem;}
.idark-slab{margin:0;padding:1.15rem 1.2rem;border-radius:16px;border:1px solid var(--border);background:var(--surface);box-shadow:var(--shadow-soft);}
.idark-slab h2{margin:0 0 .65rem;font-size:1.2rem;font-weight:700;color:var(--text-main);}
.idark-slab h3{margin:1rem 0 .45rem;font-size:1rem;font-weight:700;color:var(--text-main);}
.idark-slab p{margin:0 0 .75rem;font-size:.95rem;line-height:1.6;color:var(--text-muted);}
.idark-slab p:last-child{margin-bottom:0;}
.idark-dl{margin:0;display:grid;gap:.55rem;}
.idark-dl div{display:grid;gap:.15rem;padding-bottom:.55rem;border-bottom:1px solid var(--border);}
.idark-dl div:last-child{border-bottom:0;padding-bottom:0;}
.idark-dl dt{font-size:.78rem;font-weight:700;letter-spacing:.05em;text-transform:uppercase;color:var(--text-muted);}
.idark-dl dd{margin:0;font-size:.9rem;line-height:1.5;color:var(--text-main);}
.idark-table-wrap{overflow-x:auto;margin:.5rem 0 0;border-radius:12px;border:1px solid var(--border);}
.idark-table{width:100%;border-collapse:collapse;font-size:.875rem;}
.idark-table th,.idark-table td{padding:.6rem .75rem;text-align:left;border-bottom:1px solid var(--border);}
.idark-table th{background:var(--surface-muted);color:var(--text-main);font-weight:700;}
.idark-table td{color:var(--text-muted);}
.idark-table tr:last-child td{border-bottom:0;}
.idark-callout{margin:1rem 0 0;padding:.85rem 1rem;border-left:4px solid var(--primary);border-radius:0 12px 12px 0;background:color-mix(in srgb,var(--primary) 8%,var(--surface-muted));font-size:.9rem;line-height:1.55;color:var(--text-main);}
.idark-aside-stick{display:flex;flex-direction:column;gap:1rem;}
.idark-tip-card{margin:0;padding:1rem;border-radius:14px;border:1px solid var(--border);background:linear-gradient(160deg,var(--surface-muted),var(--surface));}
.idark-tip-card h3{margin:0 0 .5rem;font-size:.85rem;font-weight:700;text-transform:uppercase;letter-spacing:.05em;color:var(--text-main);}
.idark-tip-card ul{margin:0;padding-left:1.1rem;font-size:.85rem;line-height:1.55;color:var(--text-muted);}
.idark-tip-card li{margin-bottom:.35rem;}
.idark-tip-card li:last-child{margin-bottom:0;}
.idark-list-plain{margin:.4rem 0 0;padding-left:1.15rem;color:var(--text-muted);font-size:.92rem;line-height:1.55;}
.idark-list-plain li{margin-bottom:.4rem;}