/* ============================================================
   数学实验室 —— 深色玻璃拟态风格，零外部依赖
   ============================================================ */

:root {
  --primary: #7c5cff;
  --cyan: #22d3ee;
  --pink: #ff5ca8;
  --amber: #ffb347;
  --text: #e9ecff;
  --text-dim: #9aa3c7;
  --panel-bg: rgba(255, 255, 255, .06);
  --panel-border: rgba(255, 255, 255, .12);
  --radius: 20px;
}

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

html, body { height: 100%; }

body {
  font-family: system-ui, -apple-system, "Segoe UI", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: radial-gradient(circle at 50% 30%, #171a3a, #0b0e20);
  background-attachment: fixed;
  min-height: 100vh;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

/* ---------------- 顶部栏 ---------------- */

.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 26px;
  background: rgba(11, 14, 32, .72);
  border-bottom: 1px solid var(--panel-border);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.brand { display: flex; align-items: center; gap: 12px; }

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border-radius: 12px;
  font-size: 22px;
  font-weight: 700;
  color: #fff;
  background: linear-gradient(135deg, var(--primary), #5438d8);
  box-shadow: 0 6px 18px rgba(124, 92, 255, .4);
}

.logo {
  font-size: 21px;
  font-weight: 700;
  letter-spacing: 2px;
  background: linear-gradient(90deg, #fff, #b9c0ff);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.btn-ghost {
  display: inline-block;
  padding: 9px 18px;
  border-radius: 12px;
  border: 1px solid var(--panel-border);
  background: rgba(255, 255, 255, .05);
  color: var(--text);
  font-size: 14px;
  text-decoration: none;
  transition: all .2s ease;
  white-space: nowrap;
}
.btn-ghost:hover { border-color: var(--primary); color: var(--cyan); transform: translateY(-1px); }

/* ---------------- 标签栏 ---------------- */

.tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  padding: 20px 26px 4px;
  max-width: 1280px;
  margin: 0 auto;
}

.tab-btn {
  appearance: none;
  border: 1px solid var(--panel-border);
  background: rgba(255, 255, 255, .04);
  color: var(--text-dim);
  font-size: 15px;
  font-family: inherit;
  padding: 10px 20px;
  border-radius: 14px;
  cursor: pointer;
  transition: all .22s ease;
}
.tab-btn:hover { color: var(--text); border-color: rgba(124, 92, 255, .55); }
.tab-btn.active {
  color: #fff;
  border-color: transparent;
  background: linear-gradient(135deg, rgba(124, 92, 255, .92), rgba(92, 62, 216, .92));
  box-shadow: 0 8px 22px rgba(124, 92, 255, .38);
}

/* ---------------- 主布局 ---------------- */

.app {
  max-width: 1280px;
  margin: 0 auto;
  padding: 16px 26px 30px;
}

.tab-panel { display: none; animation: fadeUp .35s ease; }
.tab-panel.active { display: block; }

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(10px); }
  to   { opacity: 1; transform: translateY(0); }
}

.glass {
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}

.panel { padding: 18px 20px; }

.ctl-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 22px;
  align-items: flex-start;
  margin-bottom: 16px;
}
.ctl-bar.wrap { align-items: center; }
.ctl-block { display: flex; flex-direction: column; gap: 9px; min-width: 230px; }
.ctl-block.grow { flex: 1 1 280px; }

.ctl-title {
  font-size: 13px;
  color: var(--text-dim);
  letter-spacing: .5px;
}

.ctl-row-line {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 8px;
}

/* ---------------- 分段按钮 / 小按钮 ---------------- */

.seg {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.seg-btn {
  appearance: none;
  border: 1px solid var(--panel-border);
  background: rgba(255, 255, 255, .04);
  color: var(--text-dim);
  font-size: 13.5px;
  font-family: inherit;
  padding: 8px 14px;
  border-radius: 11px;
  cursor: pointer;
  transition: all .18s ease;
  white-space: nowrap;
}
.seg-btn:hover { color: #fff; border-color: rgba(124, 92, 255, .6); }
.seg-btn.active {
  color: #fff;
  border-color: rgba(34, 211, 238, .65);
  background: rgba(34, 211, 238, .14);
  box-shadow: inset 0 0 0 1px rgba(34, 211, 238, .25);
}

.seg-mini { display: flex; flex-direction: column; gap: 6px; margin-top: 2px; }
.seg-title { font-size: 12.5px; color: var(--text-dim); }

.chip-row { display: flex; flex-wrap: wrap; gap: 8px; }

.chip-btn {
  appearance: none;
  border: 1px solid rgba(124, 92, 255, .55);
  background: rgba(124, 92, 255, .12);
  color: #cfc6ff;
  font-size: 13px;
  font-family: inherit;
  padding: 8px 14px;
  border-radius: 999px;
  cursor: pointer;
  transition: all .18s ease;
}
.chip-btn:hover { background: rgba(124, 92, 255, .28); color: #fff; }
.chip-btn.primary {
  border-color: transparent;
  background: linear-gradient(135deg, var(--primary), #5e3de0);
  color: #fff;
  box-shadow: 0 6px 16px rgba(124, 92, 255, .35);
}
.chip-btn.primary:hover { filter: brightness(1.12); }
.chip-btn:disabled { opacity: .45; cursor: not-allowed; }

/* ---------------- 滑块 / 数字输入 ---------------- */

.num-line { display: flex; gap: 10px; align-items: center; }

.slider {
  -webkit-appearance: none;
  appearance: none;
  flex: 1 1 auto;
  width: 100%;
  height: 6px;
  border-radius: 999px;
  background: linear-gradient(90deg, rgba(124, 92, 255, .55), rgba(34, 211, 238, .35));
  outline: none;
  cursor: pointer;
}
.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 19px;
  height: 19px;
  border-radius: 50%;
  background: #fff;
  border: 4px solid var(--primary);
  box-shadow: 0 2px 10px rgba(124, 92, 255, .6);
  transition: transform .12s ease;
}
.slider::-webkit-slider-thumb:hover { transform: scale(1.15); }
.slider::-moz-range-thumb {
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background: #fff;
  border: 4px solid var(--primary);
  box-shadow: 0 2px 10px rgba(124, 92, 255, .6);
}
.slider:disabled { opacity: .4; cursor: not-allowed; }

.slider-val {
  font-size: 13px;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.num-input {
  width: 84px;
  padding: 7px 9px;
  border-radius: 10px;
  border: 1px solid var(--panel-border);
  background: rgba(0, 0, 0, .25);
  color: var(--text);
  font-size: 14px;
  font-family: inherit;
  font-variant-numeric: tabular-nums;
}
.num-input:focus { outline: none; border-color: var(--primary); }

.riem-state { font-size: 12.5px; color: var(--text-dim); }

/* ---------------- 画布卡片 ---------------- */

.canvas-card {
  position: relative;
  padding: 12px 14px 14px;
  margin-bottom: 16px;
}
.canvas-card canvas { display: block; width: 100%; }

#cvGauss { height: 440px; }
#cvPiErr { height: 460px; }
#cvTime  { height: 190px; }
#cvFreq  { height: 300px; }

.card-cap {
  font-size: 13px;
  color: var(--text-dim);
  padding: 2px 4px 10px;
  letter-spacing: .4px;
}

.peak-hint { color: var(--cyan); margin-left: 8px; }

/* ---------------- 读数卡片 ---------------- */

.read-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-bottom: 14px;
}
.read-grid.four { grid-template-columns: repeat(4, 1fr); }

.read-cell {
  background: rgba(255, 255, 255, .04);
  border: 1px solid rgba(255, 255, 255, .08);
  border-radius: 14px;
  padding: 13px 16px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.rd-k { font-size: 12.5px; color: var(--text-dim); }
.rd-v {
  font-size: 21px;
  font-weight: 650;
  font-variant-numeric: tabular-nums;
  word-break: break-all;
}
.rd-v.cyan  { color: var(--cyan); }
.rd-v.pink  { color: var(--pink); }
.rd-v.amber { color: var(--amber); }

.insight {
  font-size: 13.5px;
  color: var(--text-dim);
  line-height: 1.8;
  padding: 4px 8px;
  border-left: 3px solid rgba(124, 92, 255, .55);
  background: rgba(124, 92, 255, .06);
  border-radius: 0 12px 12px 0;
}

/* ---------------- 圆周率页 ---------------- */

.formula-box {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  font-size: 19px;
  padding: 8px 14px;
  background: rgba(124, 92, 255, .1);
  border: 1px solid rgba(124, 92, 255, .3);
  border-radius: 14px;
  min-width: 280px;
}
.frac { display: inline-flex; flex-direction: column; align-items: center; font-size: .82em; line-height: 1.25; }
.frac .num { border-bottom: 1.5px solid currentColor; padding: 0 5px 2px; }
.frac .den { padding: 2px 5px 0; }
.f-op { font-size: .9em; color: var(--text-dim); }
.f-sum { font-size: 1.15em; position: relative; }
.f-sum sub, .f-sum sup { font-size: .55em; }

.pi-grid {
  display: grid;
  grid-template-columns: minmax(340px, 5fr) 6fr;
  gap: 16px;
  margin-bottom: 14px;
}

.digit-panel { padding: 20px; display: flex; flex-direction: column; gap: 14px; }
.digit-head { display: flex; flex-direction: column; gap: 2px; }
.digit-tag { font-size: 14px; color: var(--text-dim); letter-spacing: 1px; }
.digit-tag.dim { color: #737ca6; }
.digit-sub { font-size: 12.5px; color: var(--amber); }

.digit-line {
  display: flex;
  align-items: baseline;
  gap: 12px;
  flex-wrap: wrap;
  border-bottom: 1px dashed rgba(255, 255, 255, .1);
  padding-bottom: 10px;
}
.digits {
  font-size: 27px;
  font-weight: 700;
  letter-spacing: 1.5px;
  font-variant-numeric: tabular-nums;
  word-break: break-all;
}
.true-digits { font-size: 20px; font-weight: 500; color: #8b93bd; letter-spacing: 1.2px; }
.digits .ch { display: inline-block; position: relative; }
.digits .ch.ok   { color: var(--cyan); text-shadow: 0 0 12px rgba(34, 211, 238, .45); }
.digits .ch.bad  { color: var(--pink); text-shadow: 0 0 12px rgba(255, 92, 168, .45); }
.digits .ch.rest { color: #aeb6dd; }
.digits .ch.sym  { color: var(--text-dim); }

.pi-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}
.pi-stats .rd-v { font-size: 18px; }

.step-box {
  margin-top: auto;
  border-radius: 14px;
  border: 1px solid rgba(255, 255, 255, .08);
  background: rgba(0, 0, 0, .18);
  overflow: hidden;
  max-height: 190px;
  overflow-y: auto;
}
.step-head, .step-row {
  display: grid;
  grid-template-columns: 42px 1fr 1.2fr;
  gap: 6px;
  padding: 7px 12px;
  font-size: 12px;
  align-items: center;
}
.step-head {
  position: sticky;
  top: 0;
  background: rgba(23, 26, 58, .95);
  color: var(--text-dim);
  z-index: 2;
}
.step-list { list-style: none; }
.step-row { border-top: 1px solid rgba(255, 255, 255, .05); font-variant-numeric: tabular-nums; }
.step-row .s-k { color: var(--amber); font-weight: 700; }
.step-row .s-pi { color: #cfd6ff; font-size: 11.5px; }
.step-row .s-err { color: var(--pink); font-size: 11.5px; text-align: right; }
.step-row.latest { background: rgba(34, 211, 238, .08); }

.chart-legend {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 4px 6px 2px;
  font-size: 12.5px;
  color: var(--text-dim);
  flex-wrap: wrap;
}
.lg-dot { width: 12px; height: 4px; border-radius: 2px; display: inline-block; margin-left: 10px; }
.lg-dot:first-child { margin-left: 0; }
.lg-dot.ram { background: var(--cyan); }
.lg-dot.lei { background: var(--pink); }
.lg-dot.poly { background: var(--amber); }

/* ---------------- 傅里叶页 ---------------- */

.comps-block { min-width: 340px; flex: 2 1 420px; }
.comp-rows { display: flex; flex-direction: column; gap: 10px; }

.comp-row {
  display: grid;
  grid-template-columns: 30px 1fr 1fr 1fr;
  gap: 10px;
  align-items: center;
  padding: 10px 12px;
  border-radius: 14px;
  border: 1px solid rgba(255, 255, 255, .08);
  background: rgba(0, 0, 0, .18);
}
.comp-row.off { opacity: .45; }
.comp-tag {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  font-weight: 700;
  color: #0b0e20;
}
.comp-cell { display: flex; flex-direction: column; gap: 4px; min-width: 0; }
.comp-cell label { font-size: 11.5px; color: var(--text-dim); display: flex; justify-content: space-between; }
.comp-cell .cv { color: var(--cyan); font-variant-numeric: tabular-nums; }

.check-line {
  display: flex;
  align-items: center;
  gap: 9px;
  font-size: 13.5px;
  color: var(--text);
  cursor: pointer;
}
.check-line input { width: 16px; height: 16px; accent-color: var(--primary); cursor: pointer; }

.slider-mini { display: grid; grid-template-columns: auto 1fr auto; gap: 8px; align-items: center; }
.slider-mini label { font-size: 12.5px; color: var(--text-dim); white-space: nowrap; }
.slider-mini .slider { height: 5px; }
.slider-mini .slider-val { font-size: 12px; }

.spec-card { overflow: hidden; }

.spec-tip {
  position: absolute;
  pointer-events: none;
  z-index: 10;
  transform: translate(-50%, -115%);
  padding: 7px 11px;
  border-radius: 10px;
  background: rgba(10, 12, 28, .92);
  border: 1px solid rgba(34, 211, 238, .5);
  font-size: 12.5px;
  line-height: 1.6;
  white-space: nowrap;
  box-shadow: 0 8px 22px rgba(0, 0, 0, .5);
}
.spec-tip b { color: var(--cyan); }

.tips {
  max-width: 1280px;
  margin: 0 auto;
  padding: 6px 26px 34px;
  font-size: 12.5px;
  color: #6b739c;
  text-align: center;
  line-height: 1.9;
}

/* ---------------- 自适应：手机端纵向堆叠 ---------------- */

@media (max-width: 900px) {
  .pi-grid { grid-template-columns: 1fr; }
  .read-grid, .read-grid.four { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 640px) {
  .topbar { padding: 12px 16px; }
  .logo { font-size: 18px; }
  .tabs { padding: 14px 16px 0; }
  .tab-btn { flex: 1 1 100%; font-size: 14px; }
  .app { padding: 14px 14px 24px; }
  .ctl-bar { flex-direction: column; gap: 16px; }
  .ctl-block { width: 100%; min-width: 0; }
  .read-grid, .read-grid.four { grid-template-columns: 1fr; }
  .comp-row { grid-template-columns: 26px 1fr; }
  .comp-cell { grid-column: 2 / 3; }
  #cvGauss { height: 340px; }
  #cvPiErr { height: 380px; }
  .digits { font-size: 21px; }
  .formula-box { font-size: 16px; width: 100%; }
}