:root {
  --bg: #f3efe7;
  --paper: #fffdf9;
  --ink: #1f1b17;
  --muted: #675c52;
  --line: #d9cfc2;
  --accent: #b43f28;
  --accent-soft: #f2d7cf;
  --card: #f8f4ec;
  --shadow: 0 18px 50px rgba(40, 26, 16, 0.08);
  --radius: 22px;
  --mono: "SFMono-Regular", "JetBrains Mono", "Menlo", "Monaco", monospace;
  --serif: "Iowan Old Style", "Palatino Linotype", "Book Antiqua", Palatino, Georgia, serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background:
    radial-gradient(circle at top left, rgba(180, 63, 40, 0.08), transparent 28%),
    radial-gradient(circle at top right, rgba(153, 99, 48, 0.09), transparent 26%),
    linear-gradient(180deg, #f7f3eb 0%, var(--bg) 100%);
  color: var(--ink);
  font-family: var(--serif);
  line-height: 1.6;
}

html[data-lang="en"] body [data-lang="zh"],
html[data-lang="zh"] body [data-lang="en"],
body.lang-en [data-lang="zh"],
body.lang-zh [data-lang="en"] {
  display: none !important;
}

a {
  color: inherit;
}

.shell {
  width: min(1080px, calc(100vw - 32px));
  margin: 0 auto;
  padding: 32px 0 56px;
}

.hero {
  padding: 28px;
  border: 1px solid rgba(180, 63, 40, 0.18);
  border-radius: 30px;
  background:
    linear-gradient(135deg, rgba(255, 255, 255, 0.92), rgba(255, 248, 241, 0.96)),
    var(--paper);
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
}

.hero::after {
  content: "";
  position: absolute;
  right: -60px;
  top: -70px;
  width: 220px;
  height: 220px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(180, 63, 40, 0.22), rgba(180, 63, 40, 0));
}

.hero-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
}

.eyebrow {
  display: inline-block;
  margin-bottom: 12px;
  padding: 6px 12px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 13px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  font-family: var(--mono);
}

.lang-switch {
  display: inline-flex;
  gap: 8px;
  padding: 6px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.78);
  position: relative;
  z-index: 1;
}

.lang-button {
  border: 0;
  background: transparent;
  color: var(--muted);
  border-radius: 999px;
  padding: 8px 12px;
  font-family: var(--mono);
  font-size: 12px;
  cursor: pointer;
}

.lang-button.active {
  background: var(--accent);
  color: white;
}

h1, h2, h3 {
  margin: 0;
  line-height: 1.1;
}

h1 {
  font-size: clamp(42px, 7vw, 84px);
  letter-spacing: -0.04em;
}

h2 {
  font-size: clamp(28px, 4vw, 42px);
  letter-spacing: -0.03em;
}

h3 {
  font-size: 22px;
  letter-spacing: -0.02em;
}

.lede {
  max-width: 780px;
  margin-top: 16px;
  color: var(--muted);
  font-size: 19px;
}

.meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 20px;
}

.tag {
  padding: 8px 12px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.76);
  font-size: 13px;
  font-family: var(--mono);
}

.grid {
  display: grid;
  gap: 18px;
  margin-top: 26px;
}

.cards {
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
}

.card {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.82), var(--card));
  box-shadow: var(--shadow);
  padding: 22px;
}

.card p,
.section p,
.section li {
  color: var(--muted);
}

.card a.button,
.button {
  display: inline-block;
  margin-top: 14px;
  padding: 11px 16px;
  border-radius: 999px;
  border: 1px solid var(--accent);
  background: var(--accent);
  color: white;
  text-decoration: none;
  font-family: var(--mono);
  font-size: 13px;
  cursor: pointer;
}

.button[disabled],
.button[aria-disabled="true"] {
  opacity: 0.45;
  cursor: not-allowed;
  pointer-events: none;
}

.button.secondary {
  background: transparent;
  color: var(--accent);
}

.section {
  margin-top: 20px;
  padding: 24px;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background: rgba(255, 253, 249, 0.92);
}

.section ul {
  margin: 12px 0 0;
  padding-left: 20px;
}

.prompt-wrap {
  margin-top: 18px;
  border-radius: 24px;
  overflow: hidden;
  border: 1px solid rgba(31, 27, 23, 0.12);
  box-shadow: var(--shadow);
}

.prompt-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  background: #201915;
  color: #f7f0e8;
}

.prompt-head strong {
  font-family: var(--mono);
  font-size: 13px;
  font-weight: 600;
}

.prompt {
  margin: 0;
  padding: 22px;
  background: #fffdf8;
  color: #2a231e;
  white-space: pre-wrap;
  font-size: 13px;
  line-height: 1.68;
  font-family: var(--mono);
  overflow-x: auto;
}

.inline-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 18px;
}

.mini {
  font-size: 14px;
  color: var(--muted);
}

.footer {
  margin-top: 28px;
  color: var(--muted);
  font-size: 14px;
  text-align: center;
}

.footer a {
  color: var(--accent);
  text-underline-offset: 3px;
}

.callout {
  border-left: 4px solid var(--accent);
  padding: 12px 14px;
  background: #fff6f1;
  border-radius: 14px;
}

.feature-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(280px, 0.9fr);
  gap: 18px;
  align-items: stretch;
}

.feature-card {
  border: 1px solid rgba(180, 63, 40, 0.18);
  border-radius: 24px;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.94), rgba(255, 247, 239, 0.98)),
    var(--paper);
  padding: 20px;
  box-shadow: var(--shadow);
}

.feature-card p,
.feature-card li {
  color: var(--muted);
}

.builder {
  margin-top: 18px;
}

.form-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  margin-top: 16px;
}

.field {
  display: grid;
  gap: 8px;
}

.field label,
.option strong {
  font-family: var(--mono);
  font-size: 13px;
}

.field input[type="text"] {
  width: 100%;
  padding: 13px 14px;
  border-radius: 16px;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.92);
  color: var(--ink);
  font: inherit;
}

.field input[type="text"]:focus {
  outline: 2px solid rgba(180, 63, 40, 0.2);
  border-color: var(--accent);
}

.option-list {
  display: grid;
  gap: 12px;
  margin-top: 16px;
}

.option {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  padding: 14px 16px;
  border-radius: 18px;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.88);
}

.option input {
  margin-top: 4px;
}

.option p {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.mode-note {
  margin-top: 14px;
}

.steps {
  margin: 12px 0 0;
  padding-left: 20px;
}

.author-line {
  margin-top: 20px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  font-size: 14px;
  color: var(--muted);
}

.author-line a {
  color: var(--accent);
  text-underline-offset: 3px;
}

@media (max-width: 720px) {
  .shell {
    width: min(100vw - 20px, 1080px);
    padding-top: 18px;
  }

  .hero,
  .card,
  .section {
    padding: 18px;
  }

  .prompt {
    padding: 16px;
    font-size: 12px;
  }

  .prompt-head,
  .hero-top {
    align-items: flex-start;
    flex-direction: column;
  }

  .lang-switch {
    margin-top: 6px;
  }

  .feature-grid,
  .form-grid {
    grid-template-columns: 1fr;
  }
}