/* CalcSmart / 智算 - Global Styles */
:root {
  --blue: #2563eb;
  --blue-light: #dbeafe;
  --blue-dark: #1e40af;
  --gray-50: #f8fafc;
  --gray-100: #f1f5f9;
  --gray-200: #e2e8f0;
  --gray-300: #cbd5e1;
  --gray-500: #64748b;
  --gray-700: #334155;
  --gray-900: #0f172a;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.06);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,.08), 0 4px 6px -4px rgba(0,0,0,.04);
}
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; }
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Noto Sans SC', sans-serif; color: var(--gray-900); background: var(--gray-50); line-height: 1.6; }
a { color: var(--blue); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Header */
.header { background: #fff; border-bottom: 1px solid var(--gray-200); padding: 0 1rem; position: sticky; top: 0; z-index: 100; }
.header-inner { max-width: 1100px; margin: 0 auto; display: flex; align-items: center; justify-content: space-between; height: 56px; }
.logo { font-size: 1.25rem; font-weight: 700; color: var(--blue); display: flex; align-items: center; gap: .5rem; }
.logo span { color: var(--gray-900); }
.nav { display: flex; align-items: center; gap: .25rem; flex-wrap: wrap; }
.nav a { padding: .35rem .65rem; border-radius: 8px; font-size: .875rem; color: var(--gray-700); white-space: nowrap; }
.nav a:hover, .nav a.active { background: var(--blue-light); color: var(--blue); text-decoration: none; }
.lang-btn { background: none; border: 1px solid var(--gray-300); border-radius: 8px; padding: .3rem .6rem; cursor: pointer; font-size: .85rem; color: var(--gray-700); }
.lang-btn:hover { border-color: var(--blue); color: var(--blue); }

/* Layout */
.container { max-width: 800px; margin: 0 auto; padding: 2rem 1rem 4rem; }
.container-wide { max-width: 1100px; margin: 0 auto; padding: 2rem 1rem 4rem; }
h1 { font-size: 1.75rem; margin-bottom: .5rem; }
.subtitle { color: var(--gray-500); margin-bottom: 2rem; font-size: 1rem; }

/* Cards */
.card { background: #fff; border-radius: var(--radius); box-shadow: var(--shadow); padding: 1.5rem; margin-bottom: 1.5rem; }
.card h2 { font-size: 1.15rem; margin-bottom: 1rem; }

/* Forms */
label { display: block; font-size: .875rem; font-weight: 500; color: var(--gray-700); margin-bottom: .35rem; }
input[type="number"], input[type="text"], input[type="date"], select {
  width: 100%; padding: .6rem .75rem; border: 1px solid var(--gray-300); border-radius: 8px;
  font-size: 1rem; background: #fff; color: var(--gray-900); transition: border .15s;
}
input:focus, select:focus { outline: none; border-color: var(--blue); box-shadow: 0 0 0 3px rgba(37,99,235,.15); }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin-bottom: 1rem; }
.form-group { margin-bottom: 1rem; }
.btn { display: inline-flex; align-items: center; justify-content: center; gap: .4rem; padding: .65rem 1.5rem; background: var(--blue); color: #fff; border: none; border-radius: 8px; font-size: 1rem; font-weight: 600; cursor: pointer; transition: background .15s; }
.btn:hover { background: var(--blue-dark); }
.btn-outline { background: #fff; color: var(--blue); border: 1px solid var(--blue); }
.btn-outline:hover { background: var(--blue-light); }
.btn-sm { padding: .4rem 1rem; font-size: .875rem; }

/* Results */
.result-box { background: var(--blue-light); border-radius: var(--radius); padding: 1.25rem; margin-top: 1rem; }
.result-box .big { font-size: 2rem; font-weight: 700; color: var(--blue-dark); }
.result-box .label { font-size: .85rem; color: var(--gray-500); }
.result-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 1rem; }

/* Table */
.table-wrap { overflow-x: auto; margin-top: 1rem; }
table { width: 100%; border-collapse: collapse; font-size: .85rem; }
th, td { padding: .5rem .75rem; text-align: right; border-bottom: 1px solid var(--gray-200); }
th { background: var(--gray-100); font-weight: 600; position: sticky; top: 0; }
td:first-child, th:first-child { text-align: left; }

/* Bar chart */
.bar-chart { display: flex; align-items: flex-end; gap: 2px; height: 120px; margin-top: 1rem; }
.bar { background: var(--blue); border-radius: 3px 3px 0 0; min-width: 3px; flex: 1; transition: height .3s; position: relative; }
.bar.interest { background: #f59e0b; }

/* BMI gauge */
.bmi-gauge { height: 24px; border-radius: 12px; background: linear-gradient(to right, #3b82f6 0%, #22c55e 27%, #eab308 54%, #f97316 72%, #ef4444 100%); position: relative; margin: 1.5rem 0 .5rem; }
.bmi-marker { position: absolute; top: -6px; width: 4px; height: 36px; background: var(--gray-900); border-radius: 2px; transform: translateX(-50%); transition: left .4s; }

/* Tabs */
.tabs { display: flex; gap: .25rem; margin-bottom: 1.5rem; border-bottom: 2px solid var(--gray-200); }
.tab { padding: .5rem 1rem; cursor: pointer; font-size: .9rem; font-weight: 500; color: var(--gray-500); border-bottom: 2px solid transparent; margin-bottom: -2px; transition: all .15s; }
.tab.active { color: var(--blue); border-bottom-color: var(--blue); }

/* Radio group */
.radio-group { display: flex; gap: .5rem; margin-bottom: 1rem; }
.radio-group label { display: flex; align-items: center; gap: .3rem; padding: .4rem .8rem; border: 1px solid var(--gray-300); border-radius: 8px; cursor: pointer; font-weight: 400; }
.radio-group input:checked + span { color: var(--blue); }
.radio-group label:has(input:checked) { border-color: var(--blue); background: var(--blue-light); }
.radio-group input { display: none; }

/* Tip / donate */
.donate { text-align: center; margin-top: 3rem; padding: 1.5rem; border-top: 1px solid var(--gray-200); }
.donate p { font-size: .85rem; color: var(--gray-500); margin-bottom: .5rem; }
.donate code { font-size: .75rem; background: var(--gray-100); padding: .2rem .5rem; border-radius: 4px; word-break: break-all; }

/* Footer */
.footer { text-align: center; padding: 2rem 1rem; font-size: .8rem; color: var(--gray-500); }

/* Grid for index */
.calc-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 1.25rem; }
.calc-card { background: #fff; border-radius: var(--radius); box-shadow: var(--shadow); padding: 1.5rem; transition: box-shadow .2s, transform .2s; display: block; color: inherit; }
.calc-card:hover { box-shadow: var(--shadow-lg); transform: translateY(-2px); text-decoration: none; }
.calc-card .icon { font-size: 2rem; margin-bottom: .75rem; }
.calc-card h2 { font-size: 1.1rem; margin-bottom: .35rem; }
.calc-card p { font-size: .85rem; color: var(--gray-500); }

/* Countdown share */
.share-card { background: linear-gradient(135deg, var(--blue), #7c3aed); color: #fff; border-radius: var(--radius); padding: 2rem; text-align: center; margin-top: 1.5rem; }
.share-card .days { font-size: 3.5rem; font-weight: 800; }
.share-card .text { font-size: 1.1rem; opacity: .9; }

/* Responsive */
@media (max-width: 640px) {
  .form-row { grid-template-columns: 1fr; }
  .nav { display: none; }
  h1 { font-size: 1.4rem; }
  .result-box .big { font-size: 1.5rem; }
  .header-inner { height: 48px; }
}

/* Mobile nav toggle */
.nav-toggle { display: none; background: none; border: none; font-size: 1.5rem; cursor: pointer; }
@media (max-width: 640px) {
  .nav-toggle { display: block; }
  .nav.open { display: flex; position: absolute; top: 48px; left: 0; right: 0; background: #fff; flex-direction: column; padding: .5rem; border-bottom: 1px solid var(--gray-200); box-shadow: var(--shadow); }
}

/* FAQ section */
.faq { margin-top: 2.5rem; }
.faq h2 { font-size: 1.25rem; margin-bottom: 1rem; }
.faq details { border-bottom: 1px solid var(--gray-200); padding: .75rem 0; }
.faq summary { cursor: pointer; font-weight: 500; font-size: .95rem; }
.faq details p { margin-top: .5rem; font-size: .9rem; color: var(--gray-500); }