/* 函数变形记 Function Shapeshifter — 深蓝工程绘图纸 */
* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  font-family: ui-rounded, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: #eaf3ff;
  background:
    radial-gradient(600px 400px at 90% -10%, rgba(76, 201, 240, 0.14), transparent 65%),
    radial-gradient(500px 400px at -10% 110%, rgba(255, 209, 102, 0.1), transparent 60%),
    #101a30;
  -webkit-font-smoothing: antialiased;
}

.bar { display: flex; align-items: center; justify-content: space-between; gap: 10px; padding: 14px clamp(14px, 3vw, 30px); }
.bar__title { margin: 0; font-size: clamp(18px, 2.6vw, 24px); font-weight: 800; }
.pill {
  display: inline-flex; align-items: center; gap: 6px; padding: 8px 16px;
  font: 700 13.5px/1 inherit; color: #eaf3ff; text-decoration: none;
  background: rgba(255, 255, 255, 0.07); border: 2px solid rgba(150, 190, 255, 0.4);
  border-radius: 99px; cursor: pointer; transition: all 0.18s;
}
.pill:hover { background: rgba(255, 255, 255, 0.14); border-color: #4cc9f0; transform: translateY(-1px); }

.wrap {
  display: grid;
  grid-template-columns: 320px minmax(0, 1fr);
  gap: 18px;
  padding: 4px clamp(14px, 3vw, 30px) 26px;
  max-width: 1240px;
  margin: 0 auto;
}
.panel {
  background: rgba(17, 28, 52, 0.9);
  border: 2px solid #29406e;
  border-radius: 20px;
  padding: 18px;
  box-shadow: 0 18px 44px rgba(2, 6, 18, 0.5);
}

/* tabs */
.tabs { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.tabs button {
  padding: 10px 8px; font: 700 13.5px/1.2 inherit; color: #9db4dd;
  background: #16233f; border: 2px solid #29406e; border-radius: 12px; cursor: pointer;
  transition: all 0.16s;
}
.tabs button:hover { color: #eaf3ff; border-color: #3d5a95; }
.tabs button.on { color: #101a30; background: #4cc9f0; border-color: #9ae9ff; box-shadow: 0 4px 18px rgba(76, 201, 240, 0.4); }

.eq {
  margin: 16px 0; padding: 13px 14px; text-align: center;
  font-size: 20px; font-weight: 800; letter-spacing: 0.5px; color: #ffd166;
  background: #0b1327; border: 2px dashed #33528d; border-radius: 14px;
  font-family: "STIX Two Math", "Cambria Math", Georgia, serif;
}

/* sliders */
.sliders { display: flex; flex-direction: column; gap: 14px; }
.sl label { display: flex; justify-content: space-between; font-size: 13.5px; font-weight: 700; color: #9db4dd; margin-bottom: 6px; }
.sl label b { color: #4cc9f0; font-size: 15px; }
.sl input[type="range"] { width: 100%; accent-color: #4cc9f0; height: 26px; cursor: grab; }
.sl input[type="range"]:active { cursor: grabbing; }

.info { margin-top: 16px; display: flex; flex-direction: column; gap: 8px; }
.info p {
  margin: 0; padding: 9px 12px; font-size: 13.2px; font-weight: 600; line-height: 1.5;
  color: #c8d9f5; background: #16233f; border-left: 4px solid #ffd166; border-radius: 8px;
}
.info p b { color: #ffd166; }

/* plot */
.plot-wrap { padding: 10px; display: grid; }
#plot { width: 100%; height: 100%; min-height: 420px; border-radius: 12px; display: block; }

@media (max-width: 880px) {
  .wrap { grid-template-columns: 1fr; }
  #plot { min-height: 340px; }
}

:root {
  --page-ink: #173154;
  --page-muted: #506b93;
  --page-bg: #eef6ff;
  --glow-a: rgba(76, 201, 240, 0.24);
  --glow-b: rgba(255, 209, 102, 0.2);
  --pill-bg: rgba(255, 255, 255, 0.82);
  --pill-border: #90b4db;
  --panel-bg: rgba(248, 251, 255, 0.94);
  --panel-border: #8db2d9;
  --panel-shadow: rgba(30, 72, 110, 0.18);
  --control-bg: #e6f0fb;
  --control-border: #a9c4de;
  --plot-bg: #f8fbff;
  --grid-minor: #e4edf5;
  --grid-major: #c9dbea;
  --grid-axis: #6688a8;
  --curve: #d58c00;
  --point-label: #a92f5e;
}
[data-theme="dark"] {
  --page-ink: #eaf3ff;
  --page-muted: #9db4dd;
  --page-bg: #101a30;
  --glow-a: rgba(76, 201, 240, 0.14);
  --glow-b: rgba(255, 209, 102, 0.1);
  --pill-bg: rgba(255, 255, 255, 0.07);
  --pill-border: rgba(150, 190, 255, 0.4);
  --panel-bg: rgba(17, 28, 52, 0.9);
  --panel-border: #29406e;
  --panel-shadow: rgba(2, 6, 18, 0.5);
  --control-bg: #16233f;
  --control-border: #29406e;
  --plot-bg: #0b1327;
  --grid-minor: #152544;
  --grid-major: #1e3155;
  --grid-axis: #7ea4d9;
  --curve: #ffd166;
  --point-label: #ffb3c9;
}
body {
  color: var(--page-ink);
  background: radial-gradient(600px 400px at 90% -10%, var(--glow-a), transparent 65%),
    radial-gradient(500px 400px at -10% 110%, var(--glow-b), transparent 60%), var(--page-bg);
  transition: color 0.25s, background 0.25s;
}
.bar__actions { display: flex; gap: 8px; }
.pill { color: var(--page-ink); background: var(--pill-bg); border-color: var(--pill-border); }
.pill--icon { width: 44px; height: 44px; padding: 0; justify-content: center; }
.panel { background: var(--panel-bg); border-color: var(--panel-border); box-shadow: 0 18px 44px var(--panel-shadow); }
.tabs button, .info p { color: var(--page-muted); background: var(--control-bg); border-color: var(--control-border); }
.tabs button:hover { color: var(--page-ink); }
.eq { background: var(--plot-bg); border-color: var(--panel-border); }
.sl label { color: var(--page-muted); }