:root {
  --bg: #ffffff;
  --fg: #0f172a;
  --muted: #64748b;
  --line: #e2e8f0;
  --brand: #2563eb;
  --brand-dark: #1d4ed8;
  --soft: #f8fafc;
  --ok: #16a34a;
  --radius: 12px;
  --maxw: 1180px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--fg);
  background: var(--bg);
  line-height: 1.65;
  font-size: 16px;
}
a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; }
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 20px; }

/* header */
.site-header {
  border-bottom: 1px solid var(--line);
  background: #fff;
  position: sticky; top: 0; z-index: 20;
}
.site-header .wrap { display: flex; align-items: center; gap: 18px; height: 62px; }
.logo { font-weight: 800; font-size: 20px; letter-spacing: -.4px; color: var(--fg); }
.logo span { color: var(--brand); }
.site-nav { display: flex; gap: 16px; margin-left: auto; flex-wrap: wrap; font-size: 14px; }
.site-nav a { color: var(--muted); }
.site-nav a:hover { color: var(--brand); }
.search-form { display: flex; gap: 6px; margin-left: auto; }
.search-form input {
  padding: 8px 12px; border: 1px solid var(--line); border-radius: 8px; min-width: 200px; font-size: 14px;
}
.btn {
  display: inline-block; padding: 9px 16px; border-radius: 8px;
  background: var(--brand); color: #fff; font-size: 14px; border: 0; cursor: pointer;
}
.btn:hover { background: var(--brand-dark); text-decoration: none; }

/* breadcrumb */
.crumbs { font-size: 13px; color: var(--muted); padding: 14px 0 0; }
.crumbs a { color: var(--muted); }
.crumbs span { margin: 0 6px; }

/* hero */
.hero { padding: 40px 0 24px; }
.hero h1 { font-size: 34px; line-height: 1.2; margin: 0 0 12px; letter-spacing: -.5px; }
.hero p.lead { font-size: 18px; color: var(--muted); margin: 0 0 18px; max-width: 760px; }
.hero-stats { display: flex; gap: 24px; flex-wrap: wrap; font-size: 14px; color: var(--muted); }
.hero-stats b { color: var(--fg); font-size: 18px; display: block; }

/* grid cards */
.card-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 14px; margin: 16px 0 32px; }
.card {
  border: 1px solid var(--line); border-radius: var(--radius); padding: 14px 16px;
  background: #fff; transition: box-shadow .15s, transform .15s;
}
.card:hover { box-shadow: 0 6px 18px rgba(15,23,42,.08); transform: translateY(-1px); }
.card h3 { margin: 0 0 6px; font-size: 15px; font-weight: 600; }
.card p { margin: 0; font-size: 13px; color: var(--muted); }
.card .cat { font-size: 11px; text-transform: uppercase; letter-spacing: .04em; color: var(--brand); }

/* tool app */
.tool-app {
  border: 1px solid var(--line); border-radius: var(--radius); padding: 18px;
  background: var(--soft); margin: 18px 0 26px;
}
.te-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 12px; margin-bottom: 12px; }
.te-field { display: flex; flex-direction: column; gap: 4px; font-size: 13px; color: var(--muted); }
.te-input, .te-textarea, .te-select {
  padding: 10px 12px; border: 1px solid var(--line); border-radius: 8px; font-size: 15px;
  font-family: inherit; width: 100%; background: #fff; color: var(--fg);
}
.te-textarea { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: 14px; resize: vertical; }
.te-row { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; margin: 10px 0; }
.te-btn {
  padding: 9px 14px; border: 1px solid var(--brand); background: var(--brand); color: #fff;
  border-radius: 8px; cursor: pointer; font-size: 14px; font-family: inherit;
}
.te-btn:hover { background: var(--brand-dark); text-decoration: none; }
.te-btn.te-big { font-size: 20px; padding: 22px 30px; }
.te-out {
  margin-top: 14px; padding: 14px; background: #fff; border: 1px solid var(--line); border-radius: 10px;
}
.te-out-label { font-size: 12px; text-transform: uppercase; letter-spacing: .05em; color: var(--muted); }
.te-out-value {
  font-size: 24px; font-weight: 700; margin: 6px 0 10px; word-break: break-word; color: var(--fg);
}
.te-out-actions { display: flex; gap: 8px; }
.te-copy, .te-reset { background: #fff; color: var(--brand); border: 1px solid var(--line); }
.te-stats { font-size: 13px; color: var(--muted); margin-top: 8px; }
.te-hint { font-size: 13px; color: var(--muted); }
.te-error { color: #b91c1c; font-size: 14px; }
.te-table { width: 100%; border-collapse: collapse; font-size: 14px; margin-top: 12px; }
.te-table th, .te-table td { border-bottom: 1px solid var(--line); padding: 6px 8px; text-align: left; }
.te-table th { color: var(--muted); font-weight: 600; }
.te-table-wrap { overflow-x: auto; }
.te-swatches { display: flex; gap: 4px; flex-wrap: wrap; margin: 10px 0; }
.te-sw { width: 46px; height: 46px; border-radius: 8px; border: 1px solid var(--line); }
.te-color { width: 56px; height: 38px; border: 1px solid var(--line); border-radius: 8px; background: #fff; }
.te-canvas-wrap { border: 1px dashed var(--line); border-radius: 10px; padding: 8px; margin: 10px 0; overflow: auto; }
.te-canvas-wrap canvas { max-width: 100%; }
.te-timer { text-align: center; }
.te-timer #te-time { font-size: 42px; font-weight: 800; font-variant-numeric: tabular-nums; margin: 10px 0; }
.te-report { margin-top: 12px; }
.te-metrics { display: flex; gap: 12px; flex-wrap: wrap; margin-bottom: 10px; }
.te-metric {
  border: 1px solid var(--line); border-radius: 10px; padding: 10px 14px; min-width: 110px; background: #fff;
}
.te-metric b { display: block; font-size: 20px; }
.te-metric span { font-size: 12px; color: var(--muted); }
.te-check { font-size: 13px; color: var(--muted); display: flex; gap: 6px; align-items: center; }
details.te-note { margin-top: 12px; font-size: 13px; color: var(--muted); }
details.te-note summary { cursor: pointer; }
.te-formula { font-family: ui-monospace, Menlo, Consolas, monospace; background: #fff; border: 1px solid var(--line); padding: 8px; border-radius: 8px; margin-top: 8px; word-break: break-all; }

/* content */
.content h2 { font-size: 22px; margin: 32px 0 10px; letter-spacing: -.2px; }
.content h3 { font-size: 17px; margin: 20px 0 8px; }
.content p { margin: 0 0 14px; }
.content ul, .content ol { margin: 0 0 14px; padding-left: 22px; }
.content li { margin-bottom: 6px; }
.faq { border-top: 1px solid var(--line); margin-top: 30px; }
.faq details { border-bottom: 1px solid var(--line); padding: 12px 0; }
.faq summary { font-weight: 600; cursor: pointer; }
.faq p { margin: 8px 0 0; color: #334155; }

/* lists / link blocks */
.link-list { columns: 3; column-gap: 24px; font-size: 14px; }
.link-list a { display: block; padding: 3px 0; }
@media (max-width: 800px) { .link-list { columns: 2; } }
@media (max-width: 520px) { .link-list { columns: 1; } }

/* footer */
.site-footer { border-top: 1px solid var(--line); margin-top: 50px; padding: 28px 0 40px; font-size: 14px; color: var(--muted); background: var(--soft); }
.site-footer .cols { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 20px; }
.site-footer h4 { font-size: 13px; text-transform: uppercase; letter-spacing: .05em; color: var(--fg); margin: 0 0 8px; }
.site-footer a { display: block; padding: 2px 0; color: var(--muted); }
.pager { display: flex; gap: 10px; justify-content: center; margin: 24px 0; }
.notice { background: #fffbeb; border: 1px solid #fde68a; padding: 12px 14px; border-radius: 10px; font-size: 14px; margin: 16px 0; }
.badge { display: inline-block; font-size: 11px; padding: 2px 8px; border-radius: 999px; background: #eef2ff; color: var(--brand); margin-right: 6px; }