:root {
    --primary: #6d28d9;
    --primary-dark: #1f2937;
    --accent: #f59e0b;
    --bg: #f7f8fa;
    --card: #ffffff;
    --ink: #1a1f2c;
    --muted: #6b7280;
    --shadow: 0 4px 10px rgba(0,0,0,.08);
    --hi: #eab308;
    --arrow: #7c3aed;
}
* { box-sizing: border-box; }
body.sim-body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    margin: 0;
    background: var(--bg);
    color: var(--ink);
    line-height: 1.55;
}
.sim-header {
    background: linear-gradient(120deg, #4c1d95, #1e40af);
    color: #fff;
    padding: 22px 15px;
    text-align: center;
    box-shadow: var(--shadow);
}
.sim-header h1 { margin: 0; font-size: 1.7em; }
.sim-subtitle { margin: 6px 0 0; color: #cbd5e1; font-weight: 500; }
.sim-main {
    max-width: 980px;
    margin: 0 auto;
    padding: 15px;
    display: grid;
    gap: 15px;
}
.panel {
    background: var(--card);
    border-radius: 12px;
    padding: 15px 18px;
    box-shadow: var(--shadow);
    border-left: 6px solid var(--primary);
}
.panel h2 {
    color: var(--primary-dark);
    margin: 0 0 12px;
    font-size: 1.15em;
    border-bottom: 1px dashed #ddd;
    padding-bottom: 8px;
}
.ctrl-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 10px 14px;
}
.ctrl-grid label {
    display: flex;
    flex-direction: column;
    font-size: .85em;
    color: var(--muted);
    gap: 4px;
}
.ctrl-grid select, .ctrl-grid input {
    padding: 7px 8px;
    border: 1px solid #cbd5e1;
    border-radius: 6px;
    font-size: 1em;
    background: #f9fafb;
    color: var(--ink);
}
.hint { color: var(--muted); font-size: .85em; margin: 10px 0 0; line-height: 1.5; }
.hint b { color: var(--ink); }

.scene-panel .scene-wrap {
    position: relative;
    width: 100%;
}
.scene-panel #scene, .matrix-panel canvas {
    width: 100%;
    height: auto;
    display: block;
    background: #fafcff;
    border-radius: 8px;
    border: 1px solid #e5e7eb;
    cursor: pointer;
}
.scene-panel #scene-overlay {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    display: block;
    pointer-events: none;
    background: transparent;
    border: none;
}
.matrix-panel canvas { cursor: crosshair; }

/* Animation controls */
.anim-controls {
    margin-top: 10px;
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    align-items: center;
    padding: 10px 12px;
    background: #f9fafb;
    border-radius: 8px;
    border: 1px solid #e5e7eb;
}
.anim-controls button {
    padding: 6px 12px;
    border: none;
    border-radius: 6px;
    background: var(--primary);
    color: #fff;
    font-size: .88em;
    font-weight: 600;
    cursor: pointer;
    transition: background .12s;
}
.anim-controls button:hover:not(:disabled) { background: #5b21b6; }
.anim-controls button:disabled { background: #cbd5e1; cursor: not-allowed; }
#btn-replay { background: #6b7280; }
#btn-replay:hover { background: #4b5563; }
.anim-speed {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: .82em;
    color: var(--muted);
    margin-left: 8px;
}
.anim-speed select {
    padding: 4px 8px;
    border: 1px solid #cbd5e1;
    border-radius: 4px;
    background: #fff;
    font-size: .88em;
}
.anim-stage {
    margin-left: auto;
    font-family: ui-monospace, monospace;
    font-size: .82em;
    color: var(--primary);
    font-weight: 700;
}

/* QKV Trace */
.qkv-panel { border-left-color: var(--accent); }
#qkv-trace .empty {
    color: var(--muted);
    font-style: italic;
    text-align: center;
    padding: 20px;
}
.qkv-block {
    display: grid;
    grid-template-columns: 1fr;
    gap: 10px;
}
.qkv-selected {
    background: #fef9e7;
    border: 2px solid var(--hi);
    border-radius: 10px;
    padding: 10px 12px;
    font-size: .95em;
}
.qkv-selected b { color: #b45309; font-size: 1.1em; }
.qkv-scores {
    display: grid;
    gap: 4px;
}
.qkv-row {
    display: grid;
    grid-template-columns: 90px 60px 1fr 60px;
    gap: 8px;
    align-items: center;
    font-family: ui-monospace, SFMono-Regular, monospace;
    font-size: .82em;
    padding: 3px 6px;
    border-radius: 4px;
}
.qkv-row.strong { background: #f5f3ff; }
.qkv-row .tok { font-weight: 700; color: var(--ink); font-family: -apple-system, sans-serif; }
.qkv-row .score { color: var(--muted); }
.qkv-row .bar {
    height: 8px;
    background: linear-gradient(90deg, var(--primary) 0%, var(--primary) 100%);
    border-radius: 4px;
}
.qkv-row .pct { text-align: right; color: var(--primary); font-weight: 700; }

/* 8-head grid */
.heads-panel { border-left-color: var(--arrow); }
.heads-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 10px;
}
.head-card {
    background: #f9fafb;
    border: 1px solid #e5e7eb;
    border-radius: 8px;
    padding: 8px 10px;
    cursor: pointer;
    transition: transform .12s, border-color .12s;
}
.head-card:hover { border-color: var(--primary); transform: translateY(-2px); }
.head-card.active { border-color: var(--hi); background: #fef9e7; box-shadow: 0 0 0 2px rgba(234,179,8,.3); }
.head-card .head-name { font-size: .85em; font-weight: 700; color: var(--primary); margin-bottom: 4px; }
.head-card .head-hint { font-size: .72em; color: var(--muted); font-style: italic; margin-bottom: 6px; line-height: 1.3; min-height: 26px; }
.head-card canvas { display: block; width: 100%; height: 100px; border-radius: 4px; background: #fff; }

/* Log */
.log-panel { border-left-color: var(--accent); }
.log {
    background: #f9fafb;
    border-radius: 8px;
    padding: 10px 14px;
    font-size: .88em;
    line-height: 1.7;
    color: var(--ink);
}
.log h3 { color: var(--primary); margin: 8px 0 4px; font-size: 1em; }
.log p { margin: 4px 0; }
.log code {
    background: #e5e7eb;
    padding: 1px 4px;
    border-radius: 3px;
    font-family: ui-monospace, SFMono-Regular, monospace;
    font-size: .92em;
    color: #7c3aed;
}
.log ul { margin: 4px 0 8px 20px; padding: 0; }

.sim-footer {
    text-align: center;
    color: var(--muted);
    padding: 10px 5px 30px;
    font-size: .85em;
}
.sim-footer a { color: var(--primary); }

@media (min-width: 700px) {
    .sim-main { padding: 20px; gap: 18px; }
}