/* ============================================================
 * style.css —— 清爽教学风 · 浅色 · 大按钮大字号 · 高对比度
 * 布局：左侧 3D 弹性占满剩余空间，右侧面板 35%（自适应，无右侧留白）
 * 字号：使用 clamp() 随视口自适应，大屏/投屏自动放大，保证可读性
 * 响应式：窄屏（<900px）上下堆叠，移动端简单可用
 * ============================================================ */

* { margin: 0; padding: 0; box-sizing: border-box; }

:root {
  --c-bg: #f4f8fb;
  --c-panel: #ffffff;
  --c-line: #d8e3ec;
  --c-text: #1f3345;
  --c-sub: #5a7086;
  --c-primary: #1f6fb2;
  --c-primary-dark: #175685;
  --c-green: #1e9e5a;
  --c-red: #d43f3f;
  --c-purple: #b84ad3;
  --radius: 10px;
  --fs-ui: clamp(15.5px, 0.95vw, 17.5px);   /* 面板基准字号 */
}

html, body {
  height: 100%;
  font-family: "Microsoft YaHei", "PingFang SC", "Segoe UI", sans-serif;
  background: var(--c-bg);
  color: var(--c-text);
  overflow: hidden;
}

.hidden { display: none !important; }

button { font-family: inherit; cursor: pointer; }

/* ================= 顶部导航 ================= */
#topbar {
  height: 58px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 18px;
  background: var(--c-panel);
  border-bottom: 2px solid var(--c-line);
}
.brand { display: flex; align-items: baseline; gap: 12px; }
.brand-title { font-size: clamp(20px, 1.15vw, 26px); font-weight: 700; color: var(--c-primary-dark); }
.brand-sub { font-size: clamp(13px, 0.8vw, 15px); color: var(--c-sub); }

.topnav { display: flex; gap: 10px; }
.btn {
  border: 1.5px solid var(--c-line);
  background: #fff;
  color: var(--c-text);
  border-radius: 8px;
  font-size: clamp(15px, 0.9vw, 17px);
  padding: 7px 14px;
  transition: background .15s, border-color .15s;
}
.btn:hover { background: #eef5fb; border-color: var(--c-primary); }
.btn:disabled { opacity: .45; cursor: not-allowed; }

.top-btn { font-size: clamp(15px, 0.95vw, 18px); font-weight: 600; }

/* ================= 主体布局 ================= */
#layout {
  display: flex;
  height: calc(100% - 58px);
  min-height: 0;
}

/* --- 左：3D 场景（弹性占满剩余空间，避免右侧留白） --- */
#stage-wrap {
  flex: 1 1 auto;
  min-width: 0;
  position: relative;
  background: linear-gradient(180deg, #f7fbfe 0%, #eef5fa 100%);
  overflow: hidden;
}
#stage3d {
  display: block;
  width: 100%;
  height: 100%;
  touch-action: none;
}

#webgl-tip {
  position: absolute;
  top: 10px; left: 50%;
  transform: translateX(-50%);
  background: #fff3d6;
  border: 1px solid #e8c96a;
  color: #7a5b12;
  padding: 6px 16px;
  border-radius: 6px;
  font-size: clamp(14px, 0.9vw, 16px);
  z-index: 30;
}

/* 比例角标 */
.scale-badge {
  position: absolute;
  left: 12px;
  bottom: 10px;
  background: rgba(31, 111, 178, .92);
  color: #fff;
  font-size: clamp(13px, 0.85vw, 15.5px);
  padding: 4px 12px;
  border-radius: 20px;
  z-index: 20;
  pointer-events: none;
}

.scene-name {
  position: absolute;
  top: 12px;
  left: 14px;
  font-size: clamp(17px, 1.15vw, 22px);
  font-weight: 700;
  color: #2c4a63;
  background: rgba(255,255,255,.88);
  padding: 5px 14px;
  border-radius: 8px;
  border: 1px solid var(--c-line);
  z-index: 20;
  pointer-events: none;
}

.stage-indicator {
  position: absolute;
  top: 18px;
  right: 16px;
  display: flex;
  gap: 6px;
  z-index: 20;
}
.stage-dot {
  width: clamp(24px, 1.6vw, 34px);
  height: clamp(7px, 0.5vw, 10px);
  border-radius: 5px;
  background: #c9d8e4;
  transition: background .3s;
}
.stage-dot.active { background: var(--c-primary); }
.stage-dot.done { background: #79b4dd; }

/* WebGL 降级 2D 简版 */
.fallback-2d {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 14px;
  background: #f2f7fb;
  z-index: 25;
  padding: 20px;
}
.fb-title { font-size: clamp(18px, 1.15vw, 21px); font-weight: 700; color: #9a6b12; }
.fb-note { font-size: clamp(14px, 0.9vw, 16px); color: var(--c-sub); }
#fb-canvas { border: 1px solid var(--c-line); border-radius: 8px; background: #fff; max-width: 100%; }

/* ================= 对比模式浮层 ================= */
.compare-overlay {
  position: absolute;
  inset: 0;
  background: rgba(244, 248, 251, .97);
  z-index: 40;
  display: flex;
  flex-direction: column;
  padding: 22px 26px;
  overflow: auto;
}
.compare-head { display: flex; justify-content: space-between; align-items: center; margin-bottom: 16px; }
.compare-head h2 { font-size: clamp(21px, 1.35vw, 27px); color: var(--c-primary-dark); }

.compare-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(clamp(220px, 17vw, 300px), 1fr));
  gap: 16px;
}
.compare-card {
  background: #fff;
  border: 2px solid var(--c-line);
  border-radius: var(--radius);
  padding: clamp(12px, 0.9vw, 18px);
  cursor: pointer;
  transition: transform .15s, border-color .15s, box-shadow .15s;
}
.compare-card:hover {
  transform: translateY(-3px);
  border-color: var(--c-primary);
  box-shadow: 0 6px 18px rgba(31,111,178,.15);
}
.compare-card.selected { border-color: var(--c-primary); box-shadow: 0 0 0 3px rgba(31,111,178,.18); }
.cc-thumb { height: 86px; border-radius: 8px; margin-bottom: 10px; display: flex; align-items: center; justify-content: center; font-size: 34px; }
.cc-title { font-size: clamp(17px, 1.1vw, 21px); font-weight: 700; margin-bottom: 6px; }
.cc-conduct { font-size: clamp(15.5px, 1vw, 18.5px); font-weight: 700; margin-bottom: 5px; }
.cc-conduct.on { color: var(--c-green); }
.cc-conduct.off { color: var(--c-red); }
.cc-reason { font-size: clamp(14px, 0.92vw, 16.5px); color: var(--c-sub); line-height: 1.55; }
.compare-foot { margin-top: 14px; font-size: clamp(14px, 0.95vw, 16.5px); color: var(--c-sub); }

/* ================= 右侧面板 ================= */
#panel {
  flex: 0 0 35%;          /* 固定 35%，剩余空间由左侧 3D 弹性吸收，杜绝右侧留白 */
  min-width: 340px;
  max-width: 680px;       /* 超宽屏上限，避免面板过宽 */
  font-size: var(--fs-ui);
  background: var(--c-panel);
  border-left: 2px solid var(--c-line);
  overflow-y: auto;
  padding: clamp(14px, 1vw, 20px) clamp(16px, 1.1vw, 22px) 34px;
}
#panel::-webkit-scrollbar { width: 8px; }
#panel::-webkit-scrollbar-thumb { background: #c5d3de; border-radius: 4px; }

.panel-block {
  margin-bottom: clamp(14px, 1vw, 18px);
  padding: clamp(12px, 0.9vw, 17px) clamp(14px, 1vw, 19px);
  border: 1.5px solid var(--c-line);
  border-radius: var(--radius);
  background: #fdfefe;
}
.block-title {
  font-size: clamp(16.5px, 1.05vw, 19.5px);
  font-weight: 700;
  color: var(--c-primary-dark);
  margin-bottom: 10px;
  border-left: 4px solid var(--c-primary);
  padding-left: 8px;
}

/* --- 预设按钮 --- */
.preset-btns { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.preset-btn {
  border: 1.5px solid var(--c-line);
  background: #fff;
  border-radius: 8px;
  padding: clamp(9px, 0.7vw, 13px) 6px;
  font-size: clamp(15.5px, 1vw, 18px);
  font-weight: 600;
  color: var(--c-text);
  text-align: center;
  transition: all .15s;
}
.preset-btn small { display: block; font-size: clamp(12px, 0.78vw, 14px); color: var(--c-sub); font-weight: 400; margin-top: 3px; line-height: 1.4; }
.preset-btn:hover { border-color: var(--c-primary); background: #eef5fb; }
.preset-btn.active { background: var(--c-primary); border-color: var(--c-primary); color: #fff; }
.preset-btn.active small { color: #d9ecfa; }
.ghost-btn {
  margin-top: 8px;
  width: 100%;
  border: 1.5px dashed #9db8cc;
  background: #f7fafd;
  color: var(--c-primary-dark);
  font-size: clamp(14.5px, 0.92vw, 16.5px);
  padding: 9px;
  border-radius: 8px;
}
.ghost-btn:hover { border-color: var(--c-primary); background: #eef5fb; }

/* --- 电路与导电结论 --- */
#circuit-wrap { display: flex; justify-content: center; margin-bottom: 8px; }
#circuit-canvas { max-width: 100%; }

.conduct-result {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: clamp(10px, 0.75vw, 14px) clamp(12px, 0.9vw, 16px);
  border-radius: 8px;
  font-size: clamp(18.5px, 1.25vw, 23px);
  font-weight: 700;
  border: 2px solid;
  transition: all .3s;
}
.conduct-result.on {
  background: #e9f9f0;
  border-color: var(--c-green);
  color: var(--c-green);
}
.conduct-result.off {
  background: #fdefef;
  border-color: var(--c-red);
  color: var(--c-red);
}
.conduct-icon { font-size: clamp(20px, 1.3vw, 25px); }
.conduct-reason {
  margin-top: 8px;
  font-size: clamp(14.5px, 0.95vw, 17px);
  color: var(--c-sub);
  line-height: 1.6;
}

/* --- 展示区电离方程式浮层（中上） --- */
.eq-overlay {
  position: absolute;
  top: 10px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 22;
  max-width: 78%;
  background: rgba(255, 255, 255, 0.93);
  border: 1.5px solid #9db8cc;
  border-radius: 10px;
  padding: clamp(7px, 0.6vw, 11px) clamp(20px, 1.6vw, 34px);
  font-size: clamp(25px, 1.6vw, 36px);
  font-weight: 700;
  color: #14395c;
  letter-spacing: 1px;
  text-align: center;
  font-family: Georgia, "Times New Roman", "Microsoft YaHei", serif;
  pointer-events: none;
}
.eq-overlay.small {
  font-size: clamp(14.5px, 0.95vw, 17.5px);
  font-weight: 600;
  letter-spacing: 0;
  line-height: 1.6;
  font-family: "Microsoft YaHei", sans-serif;
  padding: 8px 16px;
}

/* --- 原子图示（展示区右下） --- */
.legend {
  position: absolute;
  right: 12px;
  bottom: 12px;
  z-index: 22;
  background: rgba(255, 255, 255, 0.94);
  border: 1.5px solid var(--c-line);
  border-radius: 10px;
  padding: clamp(8px, 0.6vw, 12px) clamp(12px, 0.9vw, 16px);
  pointer-events: none;
}
.lg-title { font-size: clamp(13px, 0.85vw, 15.5px); font-weight: 700; color: var(--c-primary-dark); margin-bottom: 4px; }
.lg-row { display: flex; align-items: center; gap: 6px; margin: 4px 0; font-size: clamp(13.5px, 0.88vw, 16px); color: #33475a; }
.lg-dot {
  width: clamp(13px, 0.85vw, 16px);
  height: clamp(13px, 0.85vw, 16px);
  border-radius: 50%;
  display: inline-block;
  border: 1.5px solid rgba(60, 90, 120, .5);  /* 白色圆点也能看清轮廓 */
  flex: none;
}

/* --- 操作控制 --- */
.manual-btns { display: flex; gap: 8px; margin-bottom: 12px; }
.action-btn {
  flex: 1;
  font-size: clamp(16.5px, 1.1vw, 20px);
  font-weight: 700;
  padding: clamp(11px, 0.8vw, 15px) 6px;
  border-radius: 8px;
  border: 1.5px solid var(--c-primary);
  background: var(--c-primary);
  color: #fff;
}
.action-btn:hover:not(:disabled) { background: var(--c-primary-dark); }
.action-btn:disabled { background: #dce6ee; border-color: #dce6ee; color: #93a7b8; }

.temp-ctrl { margin-bottom: 12px; }
.temp-ctrl label { display: block; font-size: clamp(15.5px, 0.98vw, 18px); font-weight: 600; margin-bottom: 6px; }
#temp-value { color: #d43f3f; font-size: clamp(18px, 1.2vw, 22px); }
#temp-slider {
  width: 100%;
  height: 10px;
  -webkit-appearance: none;
  appearance: none;
  border-radius: 5px;
  background: linear-gradient(90deg, #bcd9ee 0%, #f0b95e 60%, #e07b39 80%, #d43f3f 100%);
  outline: none;
}
#temp-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: clamp(22px, 1.5vw, 27px);
  height: clamp(22px, 1.5vw, 27px);
  border-radius: 50%;
  background: #fff;
  border: 3px solid var(--c-primary);
  cursor: pointer;
}
.temp-marks {
  display: flex;
  justify-content: space-between;
  font-size: clamp(12px, 0.8vw, 14px);
  color: var(--c-sub);
  margin-top: 4px;
}

.play-ctrl { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.play-btn {
  flex: 1;
  min-width: 92px;
  font-size: clamp(16.5px, 1.1vw, 20px);
  font-weight: 700;
  padding: clamp(10px, 0.78vw, 14px) 8px;
  border-radius: 8px;
  border: 1.5px solid var(--c-green);
  background: var(--c-green);
  color: #fff;
}
.play-btn:hover:not(:disabled) { background: #178a4d; }
.play-btn.paused-state { background: #e78a2e; border-color: #e78a2e; }

.speed-group { display: flex; align-items: center; gap: 5px; }
.speed-label { font-size: clamp(14px, 0.9vw, 16px); color: var(--c-sub); }
.speed-btn {
  font-size: clamp(14px, 0.92vw, 16.5px);
  padding: 7px 11px;
  border-radius: 6px;
  border: 1.5px solid var(--c-line);
  background: #fff;
  font-weight: 600;
}
.speed-btn.active { background: var(--c-primary); border-color: var(--c-primary); color: #fff; }

/* --- 辅助开关 --- */
.switch-row {
  display: flex;
  align-items: center;
  gap: 9px;
  font-size: clamp(15px, 0.98vw, 18px);
  padding: 8px 2px;
  cursor: pointer;
  user-select: none;
}
.switch-row input {
  width: clamp(18px, 1.1vw, 21px);
  height: clamp(18px, 1.1vw, 21px);
  accent-color: var(--c-primary);
  cursor: pointer;
  flex: none;
}

/* --- 数值面板 --- */
.num-panel { font-size: clamp(14px, 0.95vw, 16.5px); color: var(--c-sub); line-height: 1.75; }
.num-panel .real-scale { color: #7a3fa3; font-weight: 600; }
.num-panel .disclaimer { margin-top: 6px; font-style: italic; }

/* ================= 帮助页 ================= */
.help-overlay {
  position: fixed;
  inset: 0;
  background: rgba(31, 51, 69, .45);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}
.help-box {
  width: min(780px, 96vw);
  max-height: 88vh;
  background: #fff;
  border-radius: 14px;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  box-shadow: 0 12px 40px rgba(0,0,0,.25);
}
.help-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 20px;
  border-bottom: 2px solid var(--c-line);
}
.help-head h2 { color: var(--c-primary-dark); font-size: clamp(21px, 1.25vw, 25px); }
.small-btn { font-size: clamp(14px, 0.9vw, 16px); padding: 6px 13px; }

.help-tabs { display: flex; border-bottom: 1.5px solid var(--c-line); }
.help-tab {
  flex: 1;
  padding: 13px;
  font-size: clamp(16.5px, 1.05vw, 19px);
  font-weight: 600;
  background: #f2f6fa;
  border: none;
  border-right: 1px solid var(--c-line);
  color: var(--c-sub);
}
.help-tab:last-child { border-right: none; }
.help-tab.active { background: #fff; color: var(--c-primary-dark); border-bottom: 3px solid var(--c-primary); }

.help-body { overflow-y: auto; padding: 18px 24px; }
.help-pane { display: none; font-size: clamp(15.5px, 1vw, 18px); line-height: 1.9; }
.help-pane.active { display: block; }
.help-pane li { margin: 7px 0 7px 22px; }

/* ================= 超大屏（投屏 / 4K）进一步放大 ================= */
@media (min-width: 1800px) {
  #panel { flex-basis: 32%; max-width: 780px; }
  .brand-title { font-size: 28px; }
}

/* ================= 响应式：窄屏上下堆叠 ================= */
@media (max-width: 900px) {
  #layout { flex-direction: column; overflow-y: auto; }
  #stage-wrap { flex: 0 0 auto; width: 100%; height: 46vh; min-height: 320px; }
  #panel {
    flex: 1 1 auto;
    width: 100%;
    max-width: none;
    min-width: 0;
    border-left: none;
    border-top: 2px solid var(--c-line);
  }
  .brand-sub { display: none; }
  .topnav { gap: 6px; }
  .top-btn { font-size: 14px; padding: 6px 10px; }
  .eq-overlay { font-size: 19px; max-width: 92%; }
  .legend { transform: scale(.9); transform-origin: bottom right; }
}

@media (max-width: 520px) {
  .brand-title { font-size: 17px; }
  .manual-btns { flex-wrap: wrap; }
  .action-btn { min-width: 44%; }
  .play-btn { min-width: 84px; font-size: 15px; }
}

/* 减少动画模式：由 JS 在 body 上加类 */
body.reduce-motion .compare-card,
body.reduce-motion .btn,
body.reduce-motion .preset-btn {
  transition: none !important;
}