/* 4C Tool Hub — design system */
:root {
  --bg: #f7f8fc;
  --surface: #ffffff;
  --surface-2: #f1f3f9;
  --text: #10162a;
  --muted: #5a6478;
  --border: #e3e7f0;
  --accent: #5b5bd6;
  --accent-strong: #4f46e5;
  --accent-soft: #eef0ff;
  --ok: #0f9d6e;
  --warn: #d97706;
  --danger: #dc2626;
  --grad: linear-gradient(120deg, #4f46e5, #7c3aed 55%, #c026d3);
  --shadow-sm: 0 1px 2px rgba(16, 22, 42, .06);
  --shadow-md: 0 6px 24px -8px rgba(16, 22, 42, .14);
  --radius: 16px;
  --font: ui-sans-serif, system-ui, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}
[data-theme="dark"] {
  --bg: #0b1020;
  --surface: #121933;
  --surface-2: #1a2342;
  --text: #e8ecf8;
  --muted: #9aa5c1;
  --border: #263156;
  --accent: #8b8bf5;
  --accent-strong: #818cf8;
  --accent-soft: #1d2450;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, .4);
  --shadow-md: 0 8px 28px -10px rgba(0, 0, 0, .6);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; }
a { color: var(--accent-strong); text-decoration: none; }
a:hover { text-decoration: underline; }
.wrap { max-width: 1120px; margin: 0 auto; padding: 0 20px; }
.skip-link { position: absolute; left: -9999px; top: 0; background: var(--surface); padding: 10px 16px; z-index: 100; border-radius: 0 0 8px 0; }
.skip-link:focus { left: 0; }

/* ---------- header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.header-inner { display: flex; align-items: center; gap: 20px; height: 64px; }
.brand { display: inline-flex; align-items: center; gap: 10px; font-weight: 800; font-size: 1.15rem; color: var(--text); letter-spacing: -.02em; }
.brand:hover { text-decoration: none; }
.brand-logo {
  width: 34px; height: 34px; border-radius: 9px; object-fit: contain;
  background: #fff; box-shadow: var(--shadow-sm);
}
.main-nav { display: flex; gap: 4px; margin-left: auto; align-items: center; }
.main-nav a {
  color: var(--muted); font-weight: 600; font-size: .92rem;
  padding: 8px 12px; border-radius: 10px;
}
.main-nav a:hover { color: var(--text); background: var(--surface-2); text-decoration: none; }
.main-nav a.nav-all { color: var(--accent-strong); }
.header-actions { display: flex; gap: 6px; align-items: center; }
.icon-btn {
  border: 1px solid var(--border); background: var(--surface); color: var(--text);
  width: 38px; height: 38px; border-radius: 10px; cursor: pointer; font-size: 1rem;
  display: inline-grid; place-items: center;
}
.icon-btn:hover { background: var(--surface-2); }
.menu-btn { display: none; }
[data-theme="dark"] .theme-icon-dark { display: none; }
[data-theme="dark"] .theme-icon-light { display: inline; }
.theme-icon-light { display: none; }

@media (max-width: 860px) {
  .menu-btn { display: inline-grid; }
  .main-nav {
    display: none; position: absolute; top: 64px; left: 0; right: 0;
    flex-direction: column; align-items: stretch; padding: 12px 20px 16px;
    background: var(--bg); border-bottom: 1px solid var(--border); box-shadow: var(--shadow-md);
  }
  .main-nav.open { display: flex; }
  .main-nav a { padding: 12px; font-size: 1rem; }
}

/* ---------- hero ---------- */
.hero { text-align: center; padding: 72px 20px 40px; position: relative; overflow: hidden; }
.hero::before {
  content: ""; position: absolute; inset: -40% -20% auto; height: 130%;
  background:
    radial-gradient(600px 300px at 30% 20%, color-mix(in srgb, #6366f1 22%, transparent), transparent 70%),
    radial-gradient(500px 280px at 72% 10%, color-mix(in srgb, #c026d3 16%, transparent), transparent 70%);
  pointer-events: none;
}
.hero > * { position: relative; }
.hero h1 { font-size: clamp(2rem, 5vw, 3.3rem); line-height: 1.12; letter-spacing: -.03em; margin: 0 0 14px; font-weight: 800; }
.hero h1 .grad { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero p.lede { color: var(--muted); font-size: 1.12rem; max-width: 640px; margin: 0 auto 28px; }
.hero-search { max-width: 560px; margin: 0 auto; position: relative; }
.hero-search input {
  width: 100%; padding: 16px 20px 16px 48px; font-size: 1.05rem;
  border-radius: 999px; border: 1px solid var(--border); background: var(--surface);
  color: var(--text); box-shadow: var(--shadow-md); outline: none;
}
.hero-search input:focus { border-color: var(--accent); }
.hero-search .search-ico { position: absolute; left: 18px; top: 50%; translate: 0 -50%; color: var(--muted); }
.hero-chips { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; margin-top: 22px; }
.chip {
  font-size: .85rem; font-weight: 600; color: var(--muted);
  border: 1px solid var(--border); background: var(--surface);
  padding: 7px 14px; border-radius: 999px;
}
.chip:hover { color: var(--accent-strong); border-color: var(--accent); text-decoration: none; }

/* ---------- tool grids ---------- */
.tool-section { max-width: 1120px; margin: 0 auto; padding: 26px 20px 6px; }
.section-head { display: flex; align-items: baseline; gap: 14px; flex-wrap: wrap; margin-bottom: 14px; }
.section-head h2 { margin: 0; font-size: 1.35rem; letter-spacing: -.02em; }
.section-head p { margin: 0; color: var(--muted); font-size: .92rem; }
.tool-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(245px, 1fr)); gap: 14px; }
.tool-card {
  display: flex; gap: 12px; align-items: flex-start;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 16px; color: var(--text); box-shadow: var(--shadow-sm);
  transition: transform .15s ease, box-shadow .15s ease, border-color .15s ease;
}
.tool-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); border-color: color-mix(in srgb, var(--accent) 45%, var(--border)); text-decoration: none; }
.tool-icon {
  flex: 0 0 auto; display: grid; place-items: center; width: 42px; height: 42px;
  border-radius: 12px; background: var(--accent-soft); font-size: 1.25rem;
}
.tool-card-body { display: flex; flex-direction: column; gap: 2px; min-width: 0; }
.tool-card-body strong { font-size: .98rem; letter-spacing: -.01em; }
.tool-card-body span:last-child { color: var(--muted); font-size: .84rem; line-height: 1.45; }
.tool-card.hide { display: none; }

/* ---------- tool page ---------- */
.crumbs { max-width: 920px; margin: 18px auto 0; padding: 0 20px; font-size: .85rem; color: var(--muted); display: flex; gap: 8px; flex-wrap: wrap; }
.crumbs a { color: var(--muted); }
.tool-page { max-width: 920px; margin: 0 auto; padding: 10px 20px 40px; }
.tool-page > h1 { font-size: clamp(1.6rem, 3.5vw, 2.3rem); letter-spacing: -.02em; margin: 14px 0 6px; }
.tool-page > .sub { color: var(--muted); margin: 0 0 22px; font-size: 1.02rem; max-width: 720px; }

.panel {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); box-shadow: var(--shadow-sm); padding: 24px;
}
.panel + .panel { margin-top: 16px; }
.field-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 16px; }
.field { display: flex; flex-direction: column; gap: 6px; }
.field label { font-size: .85rem; font-weight: 600; color: var(--muted); }
.field input, .field select, .field textarea {
  padding: 11px 13px; border-radius: 10px; border: 1px solid var(--border);
  background: var(--bg); color: var(--text); font-size: 1rem; font-family: inherit; width: 100%;
}
.field input:focus, .field select:focus, .field textarea:focus { outline: 2px solid color-mix(in srgb, var(--accent) 55%, transparent); border-color: var(--accent); }
.field .hint { font-size: .78rem; color: var(--muted); }

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 11px 20px; border-radius: 12px; font-size: .95rem; font-weight: 700;
  border: 1px solid transparent; cursor: pointer; font-family: inherit;
  transition: filter .15s ease, transform .05s ease;
}
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--grad); color: #fff; }
.btn-primary:hover { filter: brightness(1.08); }
.btn-ghost { background: var(--surface); border-color: var(--border); color: var(--text); }
.btn-ghost:hover { background: var(--surface-2); }
.btn-row { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 18px; }

.results { margin-top: 20px; display: grid; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); gap: 12px; }
.stat {
  background: var(--surface-2); border-radius: 12px; padding: 14px 16px;
  border: 1px solid var(--border);
}
.stat .label { font-size: .78rem; font-weight: 700; text-transform: uppercase; letter-spacing: .04em; color: var(--muted); }
.stat .value { font-size: 1.45rem; font-weight: 800; letter-spacing: -.02em; margin-top: 2px; }
.stat.big { grid-column: 1 / -1; background: var(--accent-soft); border-color: color-mix(in srgb, var(--accent) 30%, var(--border)); }
.stat.big .value { font-size: 2rem; color: var(--accent-strong); }

.data-table { width: 100%; border-collapse: collapse; font-size: .9rem; margin-top: 14px; }
.data-table th, .data-table td { text-align: right; padding: 8px 10px; border-bottom: 1px solid var(--border); }
.data-table th:first-child, .data-table td:first-child { text-align: left; }
.data-table th { color: var(--muted); font-size: .78rem; text-transform: uppercase; letter-spacing: .04em; }
.table-scroll { overflow-x: auto; }

output.big-output {
  display: block; margin-top: 16px; padding: 16px; border-radius: 12px;
  background: var(--surface-2); border: 1px dashed var(--border);
  font-size: 1.05rem; word-break: break-word; white-space: pre-wrap; font-family: ui-monospace, "Cascadia Mono", Consolas, monospace;
}

/* ---------- article/content ---------- */
.prose { max-width: 920px; margin: 34px auto 0; }
.prose h2 { font-size: 1.35rem; letter-spacing: -.02em; margin: 30px 0 10px; }
.prose h3 { font-size: 1.08rem; margin: 22px 0 8px; }
.prose p, .prose li { color: color-mix(in srgb, var(--text) 88%, var(--muted)); }
.prose table { width: 100%; border-collapse: collapse; font-size: .92rem; }
.prose table th, .prose table td { border: 1px solid var(--border); padding: 8px 10px; text-align: left; }
.faq details {
  border: 1px solid var(--border); border-radius: 12px; background: var(--surface);
  padding: 0 18px; margin-bottom: 10px;
}
.faq summary { cursor: pointer; font-weight: 700; padding: 14px 0; list-style: none; position: relative; }
.faq summary::after { content: "+"; position: absolute; right: 0; color: var(--muted); font-size: 1.2rem; }
.faq details[open] summary::after { content: "–"; }
.faq details > div { padding: 0 0 14px; color: var(--muted); }

.related { max-width: 920px; margin: 36px auto 40px; padding: 0 0; }
.tool-page ~ .related, main > .related { padding: 0 20px; }
.related h2 { font-size: 1.2rem; }

.notice { background: var(--accent-soft); border: 1px solid color-mix(in srgb, var(--accent) 25%, var(--border)); border-radius: 12px; padding: 12px 16px; font-size: .9rem; color: var(--text); }

/* ---------- footer ---------- */
.site-footer { border-top: 1px solid var(--border); margin-top: 56px; background: var(--surface); }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr 1fr; gap: 28px; padding: 44px 20px 24px; }
.footer-brand p { color: var(--muted); font-size: .88rem; max-width: 300px; }
.site-footer h3 { font-size: .8rem; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); margin: 4px 0 12px; }
.site-footer ul { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 8px; }
.site-footer ul a, .site-footer ul button { color: var(--muted); font-size: .9rem; background: none; border: none; padding: 0; cursor: pointer; font-family: inherit; text-align: left; }
.site-footer ul a:hover, .site-footer ul button:hover { color: var(--text); }
.footer-bottom { display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; padding: 16px 20px 26px; border-top: 1px solid var(--border); }
.footer-bottom p { margin: 0; color: var(--muted); font-size: .82rem; }
@media (max-width: 900px) { .footer-grid { grid-template-columns: 1fr 1fr; } .footer-brand { grid-column: 1 / -1; } }

/* ---------- consent banner ---------- */
#consent-banner {
  position: fixed; bottom: 16px; left: 16px; right: 16px; z-index: 90;
  display: flex; justify-content: center;
}
#consent-banner[hidden] { display: none !important; }
.consent-inner {
  max-width: 720px; width: 100%; background: var(--surface); border: 1px solid var(--border);
  border-radius: 16px; box-shadow: var(--shadow-md); padding: 16px 20px;
  display: flex; gap: 16px; align-items: center; flex-wrap: wrap;
}
.consent-inner p { margin: 0; font-size: .88rem; color: var(--muted); flex: 1 1 320px; }
.consent-actions { display: flex; gap: 8px; }

/* ---------- misc ---------- */
.center { text-align: center; }
.mt-0 { margin-top: 0; }
.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
@media (max-width: 700px) { .two-col { grid-template-columns: 1fr; } }
.tag-ok { color: var(--ok); font-weight: 700; }
.tag-warn { color: var(--warn); font-weight: 700; }
.tag-danger { color: var(--danger); font-weight: 700; }
.visually-hidden { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
@media print {
  .site-header, .site-footer, #consent-banner, .crumbs, .related, .prose, .no-print { display: none !important; }
  body { background: #fff; color: #000; }
  .panel { border: none; box-shadow: none; padding: 0; }
}