:root {
  --bg: #f7f9fc;
  --surface: #ffffff;
  --surface-soft: #eef4f8;
  --text: #14212b;
  --muted: #607080;
  --line: #dce5ec;
  --primary: #126c72;
  --primary-dark: #0b4e54;
  --accent: #b85622;
  --success: #1f7a4d;
  --danger: #b42318;
  --shadow: 0 12px 30px rgba(20, 33, 43, .08);
  --radius: 8px;
}
* { box-sizing: border-box; }
body { margin: 0; font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; color: var(--text); background: var(--bg); line-height: 1.65; }
a { color: var(--primary); text-decoration: none; }
a:hover { color: var(--primary-dark); }
img { max-width: 100%; height: auto; }
.site-header { position: sticky; top: 0; z-index: 20; display: flex; align-items: center; justify-content: space-between; gap: 20px; padding: 14px clamp(18px, 5vw, 64px); background: rgba(255,255,255,.94); border-bottom: 1px solid var(--line); backdrop-filter: blur(14px); }
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--text); font-weight: 800; font-size: 1.05rem; }
.brand-mark, .tool-icon { display: inline-grid; place-items: center; width: 40px; height: 40px; border-radius: var(--radius); background: var(--primary); color: #fff; font-size: .8rem; font-weight: 800; }
.site-nav { display: flex; align-items: center; gap: 18px; font-weight: 650; }
.site-nav a { color: var(--text); }
.nav-toggle { display: none; width: 42px; height: 38px; border: 1px solid var(--line); background: var(--surface); border-radius: var(--radius); }
.nav-toggle span { display: block; width: 18px; height: 2px; margin: 4px auto; background: var(--text); }
.hero { display: grid; grid-template-columns: minmax(0, 1.25fr) minmax(280px, .75fr); gap: 34px; align-items: center; padding: clamp(42px, 8vw, 90px) clamp(18px, 5vw, 64px) 28px; background: linear-gradient(135deg, #e9f4f1 0%, #f8fbfd 55%, #fff3ea 100%); }
.hero h1 { max-width: 760px; margin: 0 0 14px; font-size: clamp(2.2rem, 5vw, 4.7rem); line-height: 1.02; letter-spacing: 0; }
.hero p { max-width: 720px; margin: 0 0 24px; color: var(--muted); font-size: 1.1rem; }
.hero-panel { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; box-shadow: var(--shadow); }
.hero-panel ul { padding-left: 20px; margin: 10px 0 0; }
.btn, button.btn, input[type=submit] { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 42px; padding: 10px 16px; border: 0; border-radius: var(--radius); background: var(--primary); color: #fff; font-weight: 750; cursor: pointer; }
.btn:hover { background: var(--primary-dark); color: #fff; }
.btn-secondary { background: #263641; }
.btn-light { background: var(--surface-soft); color: var(--text); }
.btn-small { min-height: 36px; padding: 8px 12px; font-size: .92rem; }
.container { width: min(1120px, calc(100% - 36px)); margin: 0 auto; padding: 34px 0; }
.page-header { padding: 36px 0 18px; }
.page-header h1 { margin: 0 0 10px; font-size: clamp(2rem, 4vw, 3.2rem); line-height: 1.08; }
.lead { color: var(--muted); font-size: 1.08rem; max-width: 820px; }
.content-section { margin: 34px 0; }
.content-section h2 { margin: 0 0 14px; font-size: clamp(1.45rem, 3vw, 2rem); line-height: 1.18; }
.content-section h3 { margin-top: 22px; }
.tools-grid, .blog-grid, .feature-grid, .steps-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 18px; }
.tool-card, .blog-card, .feature-card, .step-card, .tool-panel, .result-box, .notice { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px; box-shadow: 0 6px 18px rgba(20, 33, 43, .05); }
.tool-card:hover, .blog-card:hover { transform: translateY(-2px); box-shadow: var(--shadow); }
.tool-card, .blog-card { transition: transform .18s ease, box-shadow .18s ease; }
.tool-card h3, .blog-card h3 { margin: 14px 0 8px; line-height: 1.25; }
.tool-card p, .blog-card p, .muted { color: var(--muted); }
.search-box { width: 100%; min-height: 48px; padding: 12px 14px; border: 1px solid var(--line); border-radius: var(--radius); font: inherit; background: var(--surface); }
.ad-box { display: grid; place-items: center; min-height: 92px; margin: 26px 0; border: 1px dashed #a7b5c0; border-radius: var(--radius); background: #f9fbfc; color: #758391; font-size: .86rem; text-transform: uppercase; letter-spacing: .08em; }
.breadcrumbs ol { display: flex; flex-wrap: wrap; gap: 8px; padding: 0; margin: 0 0 12px; list-style: none; color: var(--muted); font-size: .94rem; }
.breadcrumbs li:not(:last-child)::after { content: "/"; margin-left: 8px; color: #9aa8b3; }
.two-column { display: grid; grid-template-columns: minmax(0, 1fr) 300px; gap: 28px; align-items: start; }
.sidebar { position: sticky; top: 84px; }
form label { display: block; margin: 14px 0 6px; font-weight: 700; }
input:not([type=radio]):not([type=checkbox]), select, textarea { width: 100%; min-height: 44px; padding: 10px 12px; border: 1px solid var(--line); border-radius: var(--radius); background: #fff; color: var(--text); font: inherit; }
input[type=radio], input[type=checkbox] { width: auto; min-height: 0; margin-right: 6px; }
textarea { min-height: 180px; resize: vertical; }
.form-row { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; }
.result-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 12px; margin-top: 16px; }
.metric { padding: 14px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface-soft); }
.metric strong { display: block; font-size: 1.4rem; color: var(--primary-dark); }
.success { border-color: rgba(31,122,77,.3); background: #eef8f2; color: var(--success); }
.error { border-color: rgba(180,35,24,.28); background: #fff1ef; color: var(--danger); }
.formula { font-family: ui-monospace, SFMono-Regular, Consolas, monospace; background: #f1f5f7; padding: 12px; border-radius: var(--radius); overflow-x: auto; }
.faq-list details { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 14px 16px; margin: 10px 0; }
.faq-list summary { cursor: pointer; font-weight: 750; }
.site-footer { margin-top: 40px; padding: 34px clamp(18px, 5vw, 64px); background: #16242d; color: #e8eef2; }
.footer-grid { display: grid; grid-template-columns: 1.4fr repeat(3, 1fr); gap: 22px; }
.site-footer h2 { margin: 0 0 10px; font-size: 1rem; }
.site-footer a { display: block; margin: 7px 0; color: #c7d5dd; }
.copyright { border-top: 1px solid rgba(255,255,255,.12); padding-top: 18px; color: #b6c4cc; }
@media (max-width: 860px) {
  .hero, .two-column { grid-template-columns: 1fr; }
  .tools-grid, .blog-grid, .feature-grid, .steps-grid, .result-grid, .footer-grid { grid-template-columns: 1fr 1fr; }
  .sidebar { position: static; }
}
@media (max-width: 680px) {
  .site-header { align-items: flex-start; }
  .nav-toggle { display: block; }
  .site-nav { display: none; position: absolute; left: 18px; right: 18px; top: 68px; flex-direction: column; align-items: stretch; padding: 14px; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); }
  .site-nav.is-open { display: flex; }
  .hero { padding-top: 36px; }
  .tools-grid, .blog-grid, .feature-grid, .steps-grid, .result-grid, .form-row, .footer-grid { grid-template-columns: 1fr; }
}