:root {
  --bg: #f5f8fa;
  --surface: #ffffff;
  --surface-alt: #eef3f6;
  --text: #16232b;
  --text-dim: #5b6b75;
  --border: #dce4e8;
  --primary: #0d7d6f;      /* 主色:深青绿 */
  --primary-light: #12a190;
  --accent: #ff7a45;       /* 强调色:橙 */
  --radius: 12px;
  --font-display: 'Manrope', sans-serif;
  --font-body: 'Inter', sans-serif;
}

* { box-sizing: border-box; }

/* 确保 hidden 属性始终生效,不被其他样式规则意外覆盖 */
[hidden] { display: none !important; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
h1, h2, h3 { font-family: var(--font-display); }

/* ---------- Top bar ---------- */
.topbar {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
}
.topbar-inner {
  max-width: 1040px;
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.logo {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.2rem;
  color: var(--primary);
}
.topnav { display: flex; gap: 22px; font-size: 0.9rem; color: var(--text-dim); }
.topnav a:hover { color: var(--primary); }

/* ---------- Hero ---------- */
.hero {
  max-width: 780px;
  margin: 0 auto;
  padding: 56px 24px 32px;
  text-align: center;
}
.hero h1 {
  font-size: clamp(1.8rem, 4.5vw, 2.6rem);
  font-weight: 800;
  margin: 0 0 28px;
  color: var(--text);
}

.paste-box {
  display: flex;
  align-items: center;
  gap: 0;
  background: var(--surface);
  border: 2px solid var(--border);
  border-radius: 999px;
  padding: 6px 6px 6px 22px;
  max-width: 640px;
  margin: 0 auto;
  transition: border-color 0.15s ease;
}
.paste-box:focus-within { border-color: var(--primary-light); }

#url-input {
  flex: 1;
  border: none;
  outline: none;
  background: transparent;
  font-size: 0.95rem;
  color: var(--text);
  padding: 10px 6px;
}
#url-input::placeholder { color: var(--text-dim); }

.clear-btn {
  border: none;
  background: transparent;
  color: var(--text-dim);
  font-size: 0.9rem;
  cursor: pointer;
  padding: 6px 10px;
}
.clear-btn:hover { color: var(--accent); }

.primary-btn {
  border: none;
  background: var(--primary);
  color: #fff;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.95rem;
  padding: 12px 26px;
  border-radius: 999px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: background 0.15s ease, transform 0.15s ease;
}
.primary-btn:hover { background: var(--primary-light); transform: translateY(-1px); }
.primary-btn:disabled { opacity: 0.6; cursor: wait; transform: none; }

.btn-spinner {
  width: 14px; height: 14px;
  border: 2px solid rgba(255,255,255,0.35);
  border-top-color: #fff;
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

.form-error {
  margin: 14px auto 0;
  max-width: 480px;
  color: #d0413a;
  font-size: 0.88rem;
}

/* ---------- Perk row (3 selling points) ---------- */
.perk-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 40px;
  text-align: left;
}
.perk {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
}
.perk-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px; height: 36px;
  border-radius: 10px;
  background: var(--surface-alt);
  color: var(--primary);
  font-size: 1.1rem;
  margin-bottom: 10px;
}
.perk h3 { font-size: 1rem; margin: 0 0 6px; }
.perk p { font-size: 0.85rem; color: var(--text-dim); margin: 0; }

/* ---------- Result card ---------- */
.result-section { max-width: 780px; margin: 0 auto; padding: 0 24px 40px; }
.result-card {
  display: flex;
  gap: 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  margin-top: 30px;
}
.result-media { position: relative; flex: 0 0 140px; }
.result-media img {
  width: 140px; height: 190px;
  object-fit: cover;
  border-radius: 8px;
  background: var(--surface-alt);
  display: block;
}
.duration-badge {
  position: absolute; right: 6px; bottom: 6px;
  background: rgba(0,0,0,0.65); color: #fff;
  font-size: 0.7rem; padding: 2px 6px; border-radius: 4px;
}
.result-info { flex: 1; min-width: 0; }
.result-author { font-size: 0.82rem; color: var(--primary); margin: 0 0 6px; font-weight: 600; }
.result-title {
  font-size: 1.05rem; font-weight: 700; margin: 0 0 10px;
  overflow: hidden; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical;
}
.result-stats { display: flex; gap: 14px; font-size: 0.78rem; color: var(--text-dim); margin-bottom: 16px; }
.download-actions { display: flex; flex-wrap: wrap; gap: 10px; }
.dl-btn {
  border: 1px solid var(--border);
  background: var(--surface-alt);
  color: var(--text);
  padding: 9px 16px;
  border-radius: 999px;
  font-family: inherit;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: border-color 0.15s ease, transform 0.15s ease;
}
.dl-btn:disabled { opacity: 0.6; cursor: wait; transform: none; }
.dl-btn:hover { border-color: var(--primary); transform: translateY(-1px); }
.dl-btn.primary { background: var(--primary); border-color: var(--primary); color: #fff; }

.fallback-link {
  display: inline-block;
  margin: 8px auto 0;
  font-size: 0.85rem;
  color: var(--primary);
  text-decoration: underline;
}

/* ---------- Intro + steps ---------- */
.intro {
  max-width: 700px;
  margin: 0 auto;
  padding: 48px 24px 8px;
}
.intro h2 { font-size: 1.5rem; margin: 0 0 14px; }
.intro > p { color: var(--text-dim); margin: 0 0 32px; }
.steps-title { font-size: 1.15rem; margin: 0 0 18px; }
.steps {
  list-style: none;
  counter-reset: step;
  margin: 0; padding: 0;
  display: flex; flex-direction: column; gap: 16px;
}
.steps li {
  counter-increment: step;
  position: relative;
  padding-left: 42px;
  color: var(--text-dim);
}
.steps li::before {
  content: counter(step);
  position: absolute; left: 0; top: 0;
  width: 28px; height: 28px;
  background: var(--primary);
  color: #fff;
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.85rem;
}
.steps strong { color: var(--text); }

/* ---------- Feature grid (6 icons) ---------- */
.feature-grid {
  max-width: 960px;
  margin: 40px auto 0;
  padding: 0 24px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.feature {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  text-align: center;
}
.feature-icon {
  display: block;
  font-size: 1.8rem;
  margin-bottom: 12px;
}
.feature p { margin: 0; font-size: 0.88rem; color: var(--text-dim); }

/* ---------- Platform guide blocks ---------- */
.platform-guide {
  max-width: 900px;
  margin: 56px auto 0;
  padding: 0 24px;
  display: flex;
  flex-direction: column;
  gap: 40px;
}
.platform-block {
  display: flex;
  align-items: center;
  gap: 32px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
}
.platform-block.reverse { flex-direction: row-reverse; }
.platform-text { flex: 1; }
.platform-text h3 { margin: 0 0 10px; font-size: 1.15rem; }
.platform-text p { margin: 0 0 8px; color: var(--text-dim); font-size: 0.9rem; }
.platform-icon {
  flex: 0 0 96px;
  height: 96px;
  display: flex; align-items: center; justify-content: center;
  font-size: 2.4rem;
  background: var(--surface-alt);
  border-radius: 16px;
}

/* ---------- FAQ ---------- */
.faq {
  max-width: 700px;
  margin: 56px auto 0;
  padding: 0 24px;
}
.faq h2 { font-size: 1.5rem; margin: 0 0 22px; }
.faq-item {
  border-bottom: 1px solid var(--border);
  padding: 16px 0;
}
.faq-item summary {
  cursor: pointer;
  font-weight: 600;
  list-style: none;
  position: relative;
  padding-right: 24px;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: '+';
  position: absolute; right: 0; top: 0;
  color: var(--primary);
  font-family: var(--font-display);
}
.faq-item[open] summary::after { content: '–'; }
.faq-item p { margin: 12px 0 0; color: var(--text-dim); font-size: 0.9rem; }

/* ---------- Footer ---------- */
.footer {
  max-width: 780px;
  margin: 56px auto 0;
  padding: 24px 24px 60px;
  text-align: center;
  color: var(--text-dim);
  font-size: 0.82rem;
  border-top: 1px solid var(--border);
}
.footer-links { margin: 10px 0; display: flex; justify-content: center; gap: 10px; }
.footer-links a:hover { color: var(--primary); }
.copyright { font-size: 0.75rem; }

/* ---------- Responsive ---------- */
@media (max-width: 720px) {
  .perk-row { grid-template-columns: 1fr; }
  .feature-grid { grid-template-columns: 1fr; }
  .platform-block, .platform-block.reverse { flex-direction: column; text-align: center; }
}
@media (max-width: 560px) {
  .paste-box { flex-wrap: wrap; border-radius: var(--radius); padding: 10px; }
  #url-input { width: 100%; order: 1; }
  .clear-btn { order: 2; }
  .primary-btn { order: 3; width: 100%; justify-content: center; margin-top: 8px; }
  .result-card { flex-direction: column; }
  .result-media { flex: none; }
  .result-media img { width: 100%; height: 220px; }
}

a:focus-visible, button:focus-visible, input:focus-visible, summary:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}