:root {
  --bg: #f6f1e8;
  --paper: #fffaf0;
  --ink: #1d252c;
  --muted: #637083;
  --accent: #0f766e;
  --line: #d9cdbb;
}

* {
  box-sizing: border-box;
}

html {
  height: 100%;
}

body {
  margin: 0;
  background:
    radial-gradient(circle at 12% 10%, rgba(15, 118, 110, 0.18), transparent 28rem),
    radial-gradient(circle at 88% 18%, rgba(180, 83, 9, 0.15), transparent 24rem),
    linear-gradient(135deg, #f8f0df 0%, #eef6f4 100%);
  color: var(--ink);
  font-family: "Microsoft YaHei", "PingFang SC", "Noto Sans CJK SC", sans-serif;
  min-height: 100vh;
  min-height: 100dvh;
  height: 100vh;
  height: 100dvh;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

header {
  padding: 32px 42px 18px;
}

h1 {
  margin: 0;
  font-size: clamp(28px, 4vw, 48px);
  letter-spacing: -0.03em;
}

.subtitle {
  color: var(--muted);
  font-size: 15px;
  margin-top: 10px;
  line-height: 1.7;
}

.hint {
  display: inline-flex;
  gap: 10px;
  align-items: center;
  margin-top: 14px;
  padding: 10px 14px;
  border: 1px solid rgba(15, 118, 110, 0.2);
  border-radius: 999px;
  background: rgba(15, 118, 110, 0.08);
  color: #115e59;
  font-size: 13px;
}

main {
  padding: 0 28px 32px;
  flex: 1;
  min-height: 0;
  display: flex;
}

.panel {
  background: rgba(255, 250, 240, 0.86);
  border: 1px solid var(--line);
  border-radius: 24px;
  box-shadow: 0 24px 70px rgba(29, 37, 44, 0.14);
  overflow: auto;
  min-height: 0;
  height: 100%;
  width: 100%;
  padding: 26px;
  backdrop-filter: blur(12px);
}

#diagram {
  min-width: 1500px;
}

.error {
  white-space: pre-wrap;
  color: #991b1b;
  background: #fee2e2;
  border: 1px solid #fecaca;
  padding: 16px;
  border-radius: 12px;
}

@media (max-width: 720px) {
  header {
    padding: 24px 18px 14px;
  }

  .subtitle {
    font-size: 14px;
    line-height: 1.7;
  }

  .hint {
    display: block;
    border-radius: 18px;
    line-height: 1.6;
  }

  main {
    padding: 0 18px 24px;
  }

  .panel {
    padding: 16px;
  }

  #diagram {
    min-width: 860px;
  }
}