/* Lesson Engine — Shared styles for 3D interactive lessons */
:root {
  --accent: #5dade2;
  --accent-rgb: 93,173,226;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  background: #0a0a1a; color: white;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  overflow: hidden; height: 100dvh;
}
canvas { display: block; }

/* Back link */
.back-link {
  position: fixed; top: 16px; left: 16px; z-index: 200;
  color: rgba(255,255,255,0.4); text-decoration: none; font-size: 14px;
}
.back-link:hover { color: white; }

/* Scene nav */
.scene-nav {
  position: fixed; bottom: 0; left: 0; right: 0; z-index: 200;
  background: rgba(10,10,26,0.92); backdrop-filter: blur(12px);
  border-top: 1px solid rgba(255,255,255,0.06);
  display: flex; overflow-x: auto; -webkit-overflow-scrolling: touch;
  padding: 10px 16px 24px; gap: 6px;
}
.scene-nav.hidden { display: none; }
.scene-btn {
  flex-shrink: 0; padding: 10px 16px; border-radius: 10px;
  border: 1px solid rgba(255,255,255,0.1); background: rgba(255,255,255,0.04);
  color: #888; font-size: 13px; font-weight: 600; cursor: pointer;
  transition: all 0.2s; white-space: nowrap;
}
.scene-btn.active {
  background: rgba(var(--accent-rgb), 0.2);
  border-color: rgba(var(--accent-rgb), 0.4);
  color: white;
}
.scene-btn:hover { background: rgba(255,255,255,0.08); }

/* Info panel — desktop: right side, mobile: bottom sheet */
.info-panel {
  position: fixed; z-index: 200;
  background: rgba(10,10,26,0.92); backdrop-filter: blur(16px);
  border: 1px solid rgba(255,255,255,0.06);
  overflow-y: auto; transition: transform 0.3s ease;
  top: 50px; right: 12px; width: 310px; max-height: calc(100dvh - 130px);
  border-radius: 16px; padding: 18px;
}
.info-panel h2 { font-size: 17px; margin-bottom: 4px; }
.info-panel .tagline {
  font-size: 12px; color: var(--accent); margin-bottom: 10px;
  font-weight: 600; text-transform: uppercase; letter-spacing: 0.5px;
}
.info-panel p { font-size: 13px; color: #bbb; line-height: 1.6; margin-bottom: 10px; }
.info-panel .equation {
  font-family: 'Times New Roman', Georgia, serif; font-size: 16px;
  color: #f9e79f; text-align: center; padding: 10px;
  background: rgba(255,255,255,0.04); border-radius: 8px; margin-bottom: 10px;
}
.info-panel .tip {
  font-size: 12px; color: var(--accent); font-weight: 600; margin-top: 8px;
  padding: 8px 10px; border-radius: 8px;
  background: rgba(var(--accent-rgb), 0.08);
  border-left: 3px solid rgba(var(--accent-rgb), 0.4);
}
.info-panel .try-it {
  font-size: 13px; color: var(--accent); font-weight: 600;
  text-transform: uppercase; letter-spacing: 1px; margin-top: 8px;
}
.info-panel .math-note {
  font-size: 11px; color: #555; line-height: 1.5; padding-top: 8px;
  border-top: 1px solid rgba(255,255,255,0.06); margin-top: 8px;
}

/* Panel collapse toggle (mobile only) */
.panel-toggle {
  display: none; width: 40px; height: 4px; border-radius: 2px;
  background: rgba(255,255,255,0.3); margin: 0 auto 12px; cursor: pointer;
}

/* Sliders */
.panel-slider { margin: 10px 0; }
.panel-slider label {
  font-size: 12px; color: #888;
  display: flex; justify-content: space-between; margin-bottom: 4px;
}
.panel-slider label .sv {
  color: #f9e79f; font-weight: 700;
  font-family: 'Times New Roman', Georgia, serif; font-size: 14px;
}
input[type="range"] {
  -webkit-appearance: none; width: 100%; height: 6px;
  border-radius: 3px; background: rgba(255,255,255,0.1); outline: none;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none; width: 24px; height: 24px; border-radius: 50%;
  background: var(--accent); cursor: pointer; border: 2px solid #0a0a1a;
}

/* Readout lines */
.readout-line { font-size: 13px; color: #aaa; margin: 4px 0; }
.readout-line .rv { color: #27ae60; font-weight: 700; }
.readout-line .rv.warn { color: #f39c12; }
.readout-line .rv.bad { color: #e74c3c; }

/* Mobile */
@media (max-width: 700px) {
  .info-panel {
    top: auto; right: 0; left: 0; bottom: 60px; width: 100%;
    max-height: 50dvh; border-radius: 20px 20px 0 0;
    padding: 12px 16px 16px;
  }
  .info-panel.collapsed { transform: translateY(calc(100% - 80px)); }
  .panel-toggle { display: block; }
  .info-panel h2 { font-size: 15px; }
  .info-panel p { font-size: 12px; }
  .scene-nav { padding: 8px 12px 20px; gap: 6px; }
  .scene-btn { padding: 8px 12px; font-size: 11px; }
}