:root {
  color-scheme: light;
  --ink: #1c1a16;
  --ink-soft: #5a5348;
  --paper: #f2ece0;
  --paper-2: #e8e0d1;
  --card: #fffdf6;
  --card-2: #f7f1e3;
  --line: rgba(28, 26, 22, 0.14);
  --accent: #b0442c;
  --accent-soft: rgba(176, 68, 44, 0.12);
  --shadow: 0 26px 60px -30px rgba(40, 30, 16, 0.55), 0 2px 0 rgba(255, 255, 255, 0.6) inset;
  --radius: 22px;
}

[data-theme="dark"] {
  color-scheme: dark;
  --ink: #ece7dc;
  --ink-soft: #a49c8d;
  --paper: #14161a;
  --paper-2: #191c22;
  --card: #20242b;
  --card-2: #1a1e24;
  --line: rgba(236, 231, 220, 0.16);
  --accent: #e88b70;
  --accent-soft: rgba(217, 105, 76, 0.16);
  --shadow: 0 30px 70px -34px rgba(0, 0, 0, 0.9), 0 1px 0 rgba(255, 255, 255, 0.05) inset;
}

* { box-sizing: border-box; }

html, body { min-height: 100%; }

body {
  margin: 0;
  padding: clamp(18px, 4vw, 40px) clamp(14px, 4vw, 40px);
  background:
    radial-gradient(120% 80% at 12% -10%, var(--card-2) 0%, transparent 55%),
    radial-gradient(90% 60% at 100% 0%, var(--accent-soft) 0%, transparent 60%),
    var(--paper);
  color: var(--ink);
  font: 16px/1.6 "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  overflow-wrap: break-word;
  -webkit-font-smoothing: antialiased;
}

.stage {
  width: 100%;
  max-width: 560px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: clamp(18px, 4vw, 28px);
}

.intro { display: flex; flex-direction: column; gap: 6px; }

.eyebrow {
  margin: 0;
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

h1 {
  margin: 0;
  font-size: clamp(26px, 7vw, 34px);
  line-height: 1.2;
  letter-spacing: 0.02em;
}

.lede {
  margin: 2px 0 0;
  font-size: 14px;
  color: var(--ink-soft);
  max-width: 46ch;
}

/* ---------- badge ---------- */

.badge-area { display: flex; flex-direction: column; gap: 16px; }

.badge-frame {
  perspective: 1200px;
  width: 100%;
}

.badge {
  position: relative;
  width: 100%;
  min-height: clamp(260px, 46vw, 320px);
  transform-style: preserve-3d;
  transition: transform 620ms cubic-bezier(0.22, 0.61, 0.36, 1);
}

.badge[data-side="back"] { transform: rotateY(180deg); }

.face {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: clamp(24px, 6vw, 34px);
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background:
    linear-gradient(160deg, var(--card) 0%, var(--card-2) 100%);
  box-shadow: var(--shadow);
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  overflow: hidden;
}

.face::after {
  content: "";
  position: absolute;
  inset: 10px;
  border: 1px dashed var(--line);
  border-radius: calc(var(--radius) - 10px);
  pointer-events: none;
}

.front { justify-content: flex-end; }

.back {
  transform: rotateY(180deg);
  align-items: center;
  justify-content: center;
  gap: 6px;
  text-align: center;
  background:
    radial-gradient(120% 120% at 50% 0%, var(--accent-soft) 0%, transparent 62%),
    linear-gradient(160deg, var(--card) 0%, var(--card-2) 100%);
}

.clip {
  position: absolute;
  top: clamp(16px, 4vw, 22px);
  left: 50%;
  transform: translateX(-50%);
  width: 74px;
  height: 12px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: linear-gradient(180deg, var(--paper-2), var(--card));
  box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.22);
}

.kicker {
  margin: auto 0 0;
  font-size: 10px;
  letter-spacing: 0.34em;
  text-transform: uppercase;
  color: var(--accent);
}

.name {
  margin: 0;
  font-size: clamp(34px, 11vw, 54px);
  line-height: 1.08;
  letter-spacing: 0.01em;
  font-weight: 700;
  font-family: "Noto Serif SC", "Songti SC", Georgia, "Times New Roman", serif;
}

.meta {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  font-size: 13px;
  color: var(--ink-soft);
}

.meta .sep { opacity: 0.5; }

.serial {
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.08em;
  white-space: nowrap;
}

.mode {
  margin: 2px 0 0;
  font-size: 12px;
  color: var(--ink-soft);
  opacity: 0.85;
}

.welcome {
  margin: 0;
  font-size: clamp(30px, 9.5vw, 46px);
  font-weight: 700;
  letter-spacing: 0.12em;
  font-family: "Noto Serif SC", "Songti SC", Georgia, "Times New Roman", serif;
  color: var(--ink);
}

.welcome-sub {
  margin: 0;
  font-size: 11px;
  letter-spacing: 0.4em;
  color: var(--accent);
}

/* ---------- controls ---------- */

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

button {
  font: inherit;
  min-height: 44px;
  min-width: 112px;
  padding: 10px 20px;
  border-radius: 999px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 120ms ease, background 160ms ease, border-color 160ms ease;
}

button:active:not(:disabled) { transform: translateY(1px); }

button:disabled { cursor: not-allowed; opacity: 0.45; }

.flip {
  background: var(--ink);
  color: var(--card);
  border-color: var(--ink);
  font-weight: 600;
  letter-spacing: 0.06em;
}

[data-theme="dark"] .flip { background: var(--card); color: var(--ink); }

.retry {
  background: transparent;
  color: var(--ink);
  border-color: var(--line);
}

button:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
}

.status {
  margin: 0;
  min-height: 1.5em;
  font-size: 13px;
  color: var(--ink-soft);
}

.status[data-tone="error"] { color: var(--accent); }

.foot {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  font-size: 12px;
  color: var(--ink-soft);
  opacity: 0.75;
  border-top: 1px solid var(--line);
  padding-top: 12px;
}

.foot-sep { opacity: 0.5; }

@media (prefers-reduced-motion: reduce) {
  .badge { transition: none; }
}

@media (max-width: 360px) {
  .meta { font-size: 12px; }
  button { min-width: 100%; }
}