:root {
  --paper: #f5f0e6;
  --paper-2: #efe7d6;
  --ink: #211c17;
  --ink-soft: #5a5044;
  --ink-faint: #8a8073;
  --vermilion: #b8402e;
  --vermilion-deep: #8c2e21;
  --green: #2c6b3f;
  --line: rgba(33, 28, 23, 0.14);
  --serif: "Songti SC", "STSong", "Noto Serif CJK SC", "Source Han Serif SC", Georgia, "Times New Roman", serif;
  --sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
}

* { box-sizing: border-box; }
html, body { margin: 0; }

/* `hidden` must win over the display rules below (author vs UA specificity). */
[hidden] { display: none !important; }

body {
  min-height: 100dvh;
  font-family: var(--sans);
  color: var(--ink);
  background-color: var(--paper);
  background-image:
    radial-gradient(120% 80% at 50% -10%, rgba(184, 64, 46, 0.06), transparent 60%),
    radial-gradient(100% 60% at 50% 120%, rgba(33, 28, 23, 0.06), transparent 60%);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: clamp(28px, 8vw, 64px) 22px calc(28px + env(safe-area-inset-bottom));
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: 0.5;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='140' height='140'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.035'/%3E%3C/svg%3E");
}

.wrap { width: 100%; max-width: 540px; position: relative; }

/* seal / 印章 */
.seal {
  display: inline-grid;
  place-items: center;
  width: 62px;
  height: 62px;
  border: 2px solid var(--vermilion);
  border-radius: 9px;
  color: var(--vermilion);
  font-family: var(--serif);
  font-size: 21px;
  font-weight: 600;
  letter-spacing: 2px;
  line-height: 1;
  transform: rotate(-5deg);
  box-shadow: inset 0 0 0 1px rgba(184, 64, 46, 0.35);
  opacity: 0.92;
}

header { margin-top: 22px; }

h1 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(34px, 11vw, 50px);
  letter-spacing: 1px;
  line-height: 1.1;
  margin: 0;
}

.subtitle {
  margin: 14px 0 0;
  font-size: 15px;
  color: var(--ink-soft);
  letter-spacing: 0.5px;
}

.rule { height: 1px; background: var(--line); margin: 28px 0 20px; }

/* cards */
.cards { display: flex; flex-direction: column; gap: 12px; }

.card {
  border: 1px solid var(--line);
  border-radius: 14px;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.5), rgba(255, 255, 255, 0.15));
  overflow: hidden;
}

.card-head {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px;
  margin: 0;
  background: none;
  border: 0;
  font: inherit;
  color: inherit;
  text-align: left;
  -webkit-tap-highlight-color: transparent;
}
button.card-head { cursor: pointer; }
.card.soon .card-head { cursor: default; }

.num {
  flex: none;
  width: 24px;
  text-align: center;
  font-family: var(--serif);
  font-size: 24px;
  line-height: 1;
  color: var(--vermilion);
  opacity: 0.55;
}

.card-title { flex: 1; min-width: 0; display: flex; flex-direction: column; gap: 3px; }
.card-name { font-family: var(--serif); font-weight: 600; font-size: 17px; letter-spacing: 0.5px; }
.card.soon .card-name { color: var(--ink-soft); }
.card-desc { font-size: 12.5px; line-height: 1.5; color: var(--ink-faint); }

.chev {
  flex: none;
  font-family: var(--serif);
  font-size: 24px;
  line-height: 1;
  color: var(--ink-faint);
  transition: transform 0.25s ease;
}
.card-head[aria-expanded="true"] .chev { transform: rotate(45deg); }

.tag {
  flex: none;
  align-self: center;
  font-size: 11px;
  color: var(--vermilion-deep);
  border: 1px solid rgba(184, 64, 46, 0.35);
  border-radius: 6px;
  padding: 3px 7px;
  white-space: nowrap;
}

/* tool panel */
.panel { padding: 2px 16px 18px; display: flex; flex-direction: column; gap: 14px; }

.note {
  margin: 0;
  font-size: 12.5px;
  line-height: 1.65;
  color: var(--ink-soft);
  background: rgba(184, 64, 46, 0.05);
  border-left: 2px solid var(--vermilion);
  border-radius: 0 8px 8px 0;
  padding: 10px 12px;
}
.note strong { color: var(--vermilion-deep); }

.filebtn {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 52px;
  border: 1.5px dashed rgba(184, 64, 46, 0.5);
  border-radius: 10px;
  color: var(--vermilion-deep);
  font-size: 15px;
  letter-spacing: 0.5px;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}
.filebtn:active { background: rgba(184, 64, 46, 0.07); }

.urlinput {
  width: 100%;
  min-height: 50px;
  padding: 0 14px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.6);
  font: inherit;
  font-size: 15px;
  color: var(--ink);
}
.urlinput:focus { outline: none; border-color: var(--vermilion); }
.urlinput::placeholder { color: var(--ink-faint); font-size: 13px; }

.gen {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 52px;
  border: 0;
  border-radius: 10px;
  background: var(--vermilion);
  color: #fff;
  font: inherit;
  font-size: 16px;
  font-weight: 600;
  letter-spacing: 1px;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}
.gen:active { background: var(--vermilion-deep); }
.gen:disabled { opacity: 0.55; cursor: default; }

.status { margin: 0; font-size: 13.5px; line-height: 1.55; padding: 10px 12px; border-radius: 8px; }
.status.working { color: var(--ink-soft); background: rgba(33, 28, 23, 0.05); }
.status.ok { color: var(--green); background: rgba(44, 107, 63, 0.09); }
.status.err { color: var(--vermilion-deep); background: rgba(184, 64, 46, 0.09); }

.download {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  min-height: 52px;
  border: 0;
  background: var(--vermilion);
  color: #fff;
  border-radius: 10px;
  text-decoration: none;
  font: inherit;
  font-size: 16px;
  font-weight: 600;
  letter-spacing: 1px;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}
.download:active { background: var(--vermilion-deep); }

/* opt-in "upload to diagnose" */
.diag { display: flex; flex-direction: column; gap: 8px; }
.diag-link {
  align-self: flex-start;
  padding: 0;
  background: none;
  border: 0;
  color: var(--ink-faint);
  font: inherit;
  font-size: 12.5px;
  text-decoration: underline;
  text-underline-offset: 3px;
  cursor: pointer;
}
.diag-confirm { display: flex; flex-direction: column; gap: 8px; }
.diag-note { font-size: 12px; line-height: 1.55; color: var(--ink-soft); }
.diag-go {
  align-self: flex-start;
  min-height: 40px;
  padding: 0 18px;
  border: 1px solid var(--vermilion);
  border-radius: 9px;
  background: none;
  color: var(--vermilion-deep);
  font: inherit;
  font-size: 13.5px;
  font-weight: 600;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}
.diag-go:active { background: rgba(184, 64, 46, 0.07); }
.diag-go:disabled { opacity: 0.55; }

/* footer counter */
footer { margin-top: 36px; }
.counter { display: inline-flex; align-items: baseline; gap: 9px; }
.counter-num {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 32px;
  line-height: 1;
  color: var(--vermilion);
  letter-spacing: 1px;
  font-variant-numeric: tabular-nums;
}
.counter-label { font-size: 12.5px; color: var(--ink-faint); letter-spacing: 0.5px; }

/* feedback */
.fb-toggle {
  display: block;
  margin-top: 18px;
  padding: 0;
  background: none;
  border: 0;
  color: var(--ink-faint);
  font: inherit;
  font-size: 12.5px;
  text-decoration: underline;
  text-underline-offset: 3px;
  cursor: pointer;
}
.fb-form { display: flex; flex-direction: column; gap: 10px; margin-top: 14px; }
.fb-msg,
.fb-contact {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.6);
  font: inherit;
  font-size: 14px;
  color: var(--ink);
  resize: vertical;
}
.fb-msg:focus,
.fb-contact:focus { outline: none; border-color: var(--vermilion); }
.fb-msg::placeholder,
.fb-contact::placeholder { color: var(--ink-faint); font-size: 12.5px; }
.fb-send {
  align-self: flex-start;
  min-height: 42px;
  padding: 0 20px;
  border: 0;
  border-radius: 10px;
  background: var(--vermilion);
  color: #fff;
  font: inherit;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}
.fb-send:active { background: var(--vermilion-deep); }
.fb-send:disabled { opacity: 0.55; }

/* entrance animation */
.rise { opacity: 0; animation: rise 0.7s cubic-bezier(0.2, 0.7, 0.2, 1) forwards; }
.d1 { animation-delay: 0.05s; }
.d2 { animation-delay: 0.15s; }
.d3 { animation-delay: 0.25s; }
.d4 { animation-delay: 0.35s; }
.d5 { animation-delay: 0.45s; }
.d6 { animation-delay: 0.55s; }
@keyframes rise {
  from { opacity: 0; transform: translateY(14px); }
  to { opacity: 1; transform: none; }
}
@media (prefers-reduced-motion: reduce) {
  .rise { animation: none; opacity: 1; }
  .chev { transition: none; }
}