:root {
  --bg: #f5f7fb;
  --surface: rgba(255, 255, 255, 0.92);
  --surface-strong: #ffffff;
  --text: #0f172a;
  --text-soft: #334155;
  --muted: #64748b;
  --line: rgba(15, 23, 42, 0.08);
  --primary: #2563ff;
  --primary-dark: #1d4ed8;
  --accent: #00c2a8;
  --accent-dark: #059b8c;
  --danger: #dc2626;
  --success: #0f9f6e;
  --warning: #b7791f;
  --shadow: 0 24px 70px rgba(15, 23, 42, 0.09);
  --shadow-soft: 0 14px 36px rgba(15, 23, 42, 0.07);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-height: 100vh;
  color: var(--text);
  background:
    linear-gradient(135deg, rgba(37, 99, 255, 0.08), transparent 34%),
    linear-gradient(225deg, rgba(0, 194, 168, 0.08), transparent 28%),
    linear-gradient(180deg, #f5f7fb 0%, #f8fafc 52%, #eef3fb 100%);
  font-family: "SF Pro Display", "SF Pro Text", "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
  overflow-x: hidden;
}
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(148, 163, 184, 0.11) 1px, transparent 1px),
    linear-gradient(90deg, rgba(148, 163, 184, 0.11) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: linear-gradient(180deg, rgba(15, 23, 42, 0.14), transparent 72%);
}
a { color: inherit; text-decoration: none; }
button, input, select, textarea { font: inherit; }
button { cursor: pointer; }
button:disabled { cursor: not-allowed; opacity: .62; }
.shell {
  position: relative;
  z-index: 1;
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto;
  padding: 18px 0 58px;
}
.topbar, .page-intro, .tool-card, .panel, .result-card, .content-card {
  border: 1px solid var(--line);
  background: var(--surface);
  box-shadow: var(--shadow-soft);
  backdrop-filter: blur(18px);
}
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  min-height: 70px;
  padding: 14px 18px;
  border-radius: 24px;
}
.brand { display: inline-flex; align-items: center; gap: 12px; font-size: 18px; font-weight: 850; }
.brand-mark { display: grid; place-items: center; width: 42px; height: 42px; flex: 0 0 auto; border-radius: 16px; color: #fff; background: linear-gradient(135deg, var(--primary), var(--accent)); box-shadow: 0 16px 30px rgba(37, 99, 255, .2); }
.nav { display: flex; flex-wrap: wrap; gap: 18px; color: var(--muted); font-size: 14px; font-weight: 750; }
.nav a:hover, .nav a.active { color: var(--primary); }
.breadcrumb { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin: 22px 0 -10px; color: var(--muted); font-size: 13px; font-weight: 750; }
.breadcrumb a:hover { color: var(--primary); }
.breadcrumb span::before { content: ">"; margin: 0 8px 0 0; color: rgba(100, 116, 139, .7); }
.page-intro { margin-top: 30px; padding: clamp(28px, 4.6vw, 50px); border-radius: 34px; box-shadow: var(--shadow); }
.eyebrow { display: inline-flex; align-items: center; gap: 10px; margin: 0; color: var(--primary); font-size: 13px; font-weight: 900; }
.eyebrow::before { content: ""; width: 8px; height: 8px; border-radius: 999px; background: var(--accent); box-shadow: 0 0 0 8px rgba(0, 194, 168, .12); }
h1, h2, h3, p { margin-top: 0; }
h1 { margin-bottom: 14px; font-size: clamp(38px, 5vw, 64px); line-height: 1.05; }
.lead { max-width: 800px; margin-bottom: 0; color: var(--muted); font-size: 18px; line-height: 1.78; }
.section-head { margin: 38px 0 18px; }
.section-head h2 { margin-bottom: 8px; font-size: clamp(26px, 3vw, 36px); }
.section-head p { max-width: 760px; margin-bottom: 0; color: var(--muted); line-height: 1.7; }
.tool-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; }
.tool-card { display: flex; flex-direction: column; min-height: 190px; padding: 22px; border-radius: 26px; transition: transform .18s ease, border-color .18s ease, box-shadow .18s ease; }
a.tool-card:hover { transform: translateY(-2px); border-color: rgba(37, 99, 255, .18); box-shadow: 0 22px 54px rgba(15, 23, 42, .1); }
.card-icon { display: grid; place-items: center; width: 52px; height: 52px; border-radius: 18px; color: var(--primary); background: rgba(37, 99, 255, .1); }
.card-icon.accent { color: var(--accent-dark); background: rgba(0, 194, 168, .12); }
.card-icon.warning { color: var(--warning); background: rgba(245, 158, 11, .13); }
.card-icon svg { width: 24px; height: 24px; fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }
.tool-card h3 { margin: 18px 0 8px; font-size: 18px; }
.tool-card p { flex: 1; margin-bottom: 18px; color: var(--muted); font-size: 14px; line-height: 1.65; }
.card-link { color: var(--primary); font-size: 14px; font-weight: 900; }
.workbench { display: grid; grid-template-columns: minmax(0, 1fr) minmax(320px, .88fr); gap: 18px; margin-top: 28px; }
.panel { border-radius: 28px; padding: 22px; }
.panel h2 { margin-bottom: 12px; font-size: 22px; }
.textarea, textarea, .text-input {
  width: 100%;
  min-height: 260px;
  resize: vertical;
  border: 1px solid rgba(15, 23, 42, .1);
  border-radius: 20px;
  padding: 16px;
  outline: none;
  color: var(--text);
  background: #fff;
  line-height: 1.7;
  box-shadow: inset 0 1px 0 rgba(255,255,255,.9);
}
textarea:focus, .text-input:focus { border-color: rgba(37, 99, 255, .5); box-shadow: 0 0 0 4px rgba(37, 99, 255, .1); }
.output-box { white-space: pre-wrap; overflow-wrap: anywhere; min-height: 260px; color: var(--text-soft); background: #fff; }
.short-textarea { min-height: 180px; }
.compare-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; }
.settings, .action-stack { display: grid; gap: 12px; }
.quick-actions { display: flex; flex-wrap: wrap; gap: 10px; }
.button { display: inline-flex; align-items: center; justify-content: center; min-height: 44px; padding: 0 18px; border: 0; border-radius: 15px; font-weight: 850; transition: transform .18s ease, box-shadow .18s ease; }
.button:hover { transform: translateY(-1px); }
.button.primary { color: #fff; background: linear-gradient(180deg, var(--primary), var(--primary-dark)); box-shadow: 0 14px 28px rgba(37, 99, 255, .22); }
.button.secondary { color: var(--primary); border: 1px solid rgba(37, 99, 255, .16); background: rgba(255,255,255,.85); }
.button.danger { color: #fff; background: var(--danger); }
.button.wide { width: 100%; }
.notice { display: none; margin-top: 12px; padding: 12px 14px; border-radius: 16px; font-size: 14px; font-weight: 750; line-height: 1.5; }
.notice.show { display: block; }
.notice.error { color: #991b1b; background: rgba(220, 38, 38, .1); }
.notice.success { color: #047857; background: rgba(15, 159, 110, .1); }
.hint { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.65; }
.stats-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }
.stat-card { padding: 16px; border: 1px solid var(--line); border-radius: 20px; background: rgba(255, 255, 255, .76); }
.stat-card span { display: block; color: var(--muted); font-size: 13px; font-weight: 750; }
.stat-card strong { display: block; margin-top: 6px; color: var(--primary); font-size: 28px; line-height: 1; }
.option-list { display: grid; gap: 10px; }
.check-card { display: flex; align-items: center; gap: 10px; min-height: 44px; padding: 10px 12px; border: 1px solid var(--line); border-radius: 16px; background: rgba(255,255,255,.74); color: var(--text-soft); font-weight: 750; }
.result-card, .content-card { border-radius: 24px; padding: 20px; }
.result-section { margin-top: 16px; }
.result-section h3 { margin-bottom: 8px; font-size: 16px; }
.result-list { min-height: 52px; padding: 12px; border: 1px solid var(--line); border-radius: 16px; background: rgba(255,255,255,.72); color: var(--text-soft); white-space: pre-wrap; overflow-wrap: anywhere; }
.content-stack { display: grid; gap: 16px; margin-top: 28px; }
.content-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; }
.step-list, .info-list { margin: 0; padding-left: 20px; color: var(--muted); line-height: 1.8; }
.related-tools { margin-top: 28px; padding: 22px; border: 1px solid var(--line); border-radius: 26px; background: rgba(255,255,255,.76); box-shadow: var(--shadow-soft); }
.related-tools h2 { font-size: 22px; margin-bottom: 14px; }
.related-links { display: flex; flex-wrap: wrap; gap: 10px; }
.related-links a, .related-links span { min-height: 36px; display: inline-flex; align-items: center; padding: 0 12px; border-radius: 999px; border: 1px solid rgba(37,99,255,.14); background: #fff; color: var(--primary); font-size: 14px; font-weight: 850; }
.related-links span { color: var(--muted); background: rgba(15,23,42,.05); }
.footer { padding: 34px 0 0; color: var(--muted); text-align: center; }
@media (max-width: 980px) { .tool-grid, .workbench, .content-grid, .compare-grid { grid-template-columns: 1fr; } }
@media (max-width: 720px) { .shell { width: min(100%, calc(100% - 18px)); } .topbar { align-items: flex-start; flex-direction: column; } .nav { justify-content: flex-start; gap: 14px; } .page-intro, .panel, .related-tools, .content-card { padding: 18px; } h1 { font-size: 38px; } .lead { font-size: 16px; } .tool-grid, .stats-grid { grid-template-columns: 1fr; } .button { width: 100%; } .quick-actions { display: grid; grid-template-columns: 1fr; } textarea, .textarea, .output-box { min-height: 220px; } }