/* TX4U shared design system — 2025 */
:root {
  --bg: #f5f7fa;
  --surface: #ffffff;
  --text: #1e293b;
  --muted: #64748b;
  --muted-2: #94a3b8;
  --border: #e2e8f0;
  --primary: #0ea5e9;
  --primary-hover: #0284c7;
  --primary-soft: #f0f9ff;
  --primary-text: #0369a1;
  --header: #0f172a;
  --logo: #38bdf8;
  --radius: 14px;
  --radius-sm: 10px;
  --shadow: 0 2px 12px rgba(15, 23, 42, 0.06);
  --max: 760px;
  --max-narrow: 640px;
  --font: 'Pretendard', 'Apple SD Gothic Neo', 'Malgun Gothic', system-ui, -apple-system, sans-serif;
  --danger: #ef4444;
  --warn-bg: #fef3c7;
  --warn-text: #92400e;
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}

a {
  color: var(--primary-text);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

/* ── Header ── */
.site-header {
  background: var(--header);
  color: #fff;
  padding: 14px 20px;
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: 0 1px 0 rgba(255, 255, 255, 0.06);
}
.site-header .inner {
  max-width: var(--max);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.logo {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--logo);
  letter-spacing: -0.02em;
  text-decoration: none;
}
.logo span {
  color: #fff;
}
.logo:hover {
  text-decoration: none;
  opacity: 0.95;
}
.header-nav {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}
.header-nav a {
  color: #cbd5e1;
  font-size: 0.8125rem;
  font-weight: 600;
  padding: 6px 10px;
  border-radius: 8px;
  text-decoration: none;
}
.header-nav a:hover {
  background: rgba(255, 255, 255, 0.08);
  color: #fff;
  text-decoration: none;
}

/* ── Layout ── */
main,
.wrap {
  flex: 1;
  width: 100%;
  max-width: var(--max);
  margin: 0 auto;
  padding: 20px 16px 40px;
}
.wrap--narrow {
  max-width: var(--max-narrow);
}

.page-title,
.wrap > h1 {
  font-size: clamp(1.35rem, 4vw, 1.55rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  margin: 8px 0 6px;
  line-height: 1.35;
}
.page-desc,
.meta {
  color: var(--muted);
  font-size: 0.875rem;
  margin-bottom: 20px;
  line-height: 1.7;
}
.meta {
  color: var(--muted-2);
  font-size: 0.8125rem;
}

/* ── Card ── */
.card {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 24px 22px;
  box-shadow: var(--shadow);
  margin-bottom: 16px;
  border: 1px solid rgba(226, 232, 240, 0.8);
}

/* ── Article typography ── */
.card h2,
.article h2 {
  font-size: 1.125rem;
  font-weight: 700;
  margin: 28px 0 12px;
  color: #0f172a;
  border-left: 4px solid var(--primary);
  padding-left: 10px;
  line-height: 1.4;
}
.card h2:first-child,
.article h2:first-of-type {
  margin-top: 0;
}
.card h3,
.article h3 {
  font-size: 1rem;
  font-weight: 700;
  margin: 20px 0 8px;
  color: #1e293b;
}
.card p,
.article p,
.card li,
.article li {
  font-size: 0.9375rem;
  line-height: 1.85;
  color: #475569;
}
.card ul,
.article ul,
.card ol,
.article ol {
  padding-left: 1.25rem;
  margin: 8px 0 12px;
}
.card li + li,
.article li + li {
  margin-top: 4px;
}
.card b,
.article b,
.card strong,
.article strong {
  color: var(--text);
  font-weight: 700;
}

.box {
  background: var(--primary-soft);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  font-size: 0.875rem;
  line-height: 1.75;
  color: #334155;
  margin: 14px 0;
}
.box.warn,
.disclaimer {
  background: var(--warn-bg);
  color: var(--warn-text);
  border-radius: var(--radius-sm);
  padding: 12px 14px;
  font-size: 0.8125rem;
  line-height: 1.7;
  margin: 14px 0;
}

.btn,
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 12px;
  padding: 12px 24px;
  background: var(--primary);
  color: #fff !important;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 0.9375rem;
  font-weight: 700;
  font-family: inherit;
  text-decoration: none !important;
  cursor: pointer;
  transition: background 0.15s, transform 0.1s;
}
.btn:hover,
.btn-primary:hover {
  background: var(--primary-hover);
  text-decoration: none !important;
}
.btn:active,
.btn-primary:active {
  transform: scale(0.99);
}

/* ── Forms (calculators) ── */
.field {
  margin-bottom: 14px;
}
.field label {
  display: block;
  font-weight: 600;
  font-size: 0.875rem;
  margin-bottom: 6px;
  color: #334155;
}
.field label small {
  font-weight: 400;
  color: var(--muted-2);
}
.field input,
.field select {
  width: 100%;
  padding: 12px 14px;
  border: 1.5px solid #cbd5e1;
  border-radius: var(--radius-sm);
  font-size: 1rem;
  font-family: inherit;
  background: #fff;
  color: var(--text);
  transition: border-color 0.15s, box-shadow 0.15s;
}
.field input:focus,
.field select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(14, 165, 233, 0.18);
}
.unit {
  position: relative;
}
.unit input {
  padding-right: 48px;
}
.unit::after {
  content: '만원';
  position: absolute;
  right: 14px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--muted-2);
  font-size: 0.875rem;
  pointer-events: none;
}
.flex {
  display: flex;
  gap: 12px;
}
.flex > div {
  flex: 1;
}

/* ── Results ── */
.result {
  display: none;
}
.result.is-visible,
.result.show {
  display: block;
  animation: fadeIn 0.25s ease;
}
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}
.net-box {
  background: linear-gradient(135deg, #0f172a, #1e3a5f);
  color: #fff;
  border-radius: var(--radius);
  padding: 24px 20px;
  text-align: center;
  margin-bottom: 16px;
  box-shadow: var(--shadow);
}
.net-box .small {
  color: #94a3b8;
  font-size: 0.8125rem;
}
.net-box .big {
  font-size: clamp(1.6rem, 5.5vw, 2.125rem);
  font-weight: 800;
  color: var(--logo);
  margin: 8px 0;
  font-variant-numeric: tabular-nums;
}
.row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  padding: 11px 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.9375rem;
}
.row b {
  font-size: 1.05rem;
  font-variant-numeric: tabular-nums;
  text-align: right;
}
.row.total {
  background: var(--primary-soft);
  border-radius: var(--radius-sm);
  padding: 14px 12px;
  margin-top: 8px;
  border: none;
}
.row.total b {
  color: var(--primary-text);
  font-size: 1.2rem;
}
.note {
  font-size: 0.75rem;
  color: var(--muted-2);
  margin-top: 14px;
  line-height: 1.65;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 4px;
}
td {
  padding: 10px 4px;
  border-bottom: 1px solid #f1f5f9;
  font-size: 0.875rem;
}
td:last-child {
  text-align: right;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}
td small {
  color: var(--muted-2);
  font-weight: 400;
}
.minus {
  color: var(--danger);
}
.plus {
  color: var(--primary);
}

/* ── Guide lists ── */
.guide-list {
  list-style: none;
  padding: 0;
}
.guide-list li {
  border-bottom: 1px solid var(--border);
}
.guide-list li:last-child {
  border-bottom: none;
}
.guide-list a {
  display: block;
  padding: 11px 2px;
  font-size: 0.9375rem;
  color: var(--primary-text);
  line-height: 1.45;
}
.guide-list a:hover {
  color: var(--primary-hover);
}

/* ── Ads ── */
.ad-slot {
  margin: 18px 0;
  text-align: center;
  max-width: var(--max);
  margin-left: auto;
  margin-right: auto;
  padding: 0 16px;
}
.ad-label {
  font-size: 0.6875rem;
  color: #cbd5e1;
  letter-spacing: 0.04em;
  margin-bottom: 6px;
  text-transform: uppercase;
}

/* ── Footer ── */
.site-footer {
  text-align: center;
  padding: 28px 16px 36px;
  color: var(--muted-2);
  font-size: 0.8125rem;
  border-top: 1px solid var(--border);
  background: #fafbfc;
  margin-top: auto;
}
.site-footer nav {
  margin-bottom: 10px;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 4px 10px;
}
.site-footer a {
  color: var(--primary);
  font-weight: 500;
}

/* ── Responsive ── */
@media (max-width: 480px) {
  .header-nav {
    display: none;
  }
  .card {
    padding: 18px 16px;
  }
  main,
  .wrap {
    padding: 16px 14px 32px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .result.is-visible,
  .result.show {
    animation: none;
  }
}