/* Compound Interest Calculator - shared styles */
:root {
  --color-bg: #f7f9fc;
  --color-surface: #ffffff;
  --color-border: #e3e8f0;
  --color-text: #16213e;
  --color-text-muted: #5b6785;
  --color-primary: #1d4ed8;
  --color-primary-dark: #1739a6;
  --color-accent: #10b981;
  --color-accent-soft: #d1fae5;
  --color-warning: #f59e0b;
  --shadow-card: 0 1px 2px rgba(16, 24, 40, 0.04), 0 4px 16px rgba(16, 24, 40, 0.06);
  --radius: 14px;
  --max-width: 1080px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0f1420;
    --color-surface: #171d2e;
    --color-border: #2a3350;
    --color-text: #e7ebf6;
    --color-text-muted: #9aa5c4;
    --color-primary: #5b8cff;
    --color-primary-dark: #7ea1ff;
    --color-accent: #34d399;
    --color-accent-soft: #103b2d;
    --shadow-card: 0 1px 2px rgba(0, 0, 0, 0.2), 0 4px 20px rgba(0, 0, 0, 0.35);
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--color-primary); }

.wrap {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

header.site-header {
  border-bottom: 1px solid var(--color-border);
  background: var(--color-surface);
}

.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 16px;
  padding-bottom: 16px;
  gap: 12px;
  flex-wrap: wrap;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.05rem;
  text-decoration: none;
  color: var(--color-text);
}

.brand svg { flex-shrink: 0; }

.lang-switch {
  display: flex;
  gap: 6px;
  font-size: 0.9rem;
}

.lang-switch a {
  padding: 6px 12px;
  border-radius: 999px;
  border: 1px solid var(--color-border);
  text-decoration: none;
  color: var(--color-text-muted);
}

.lang-switch a[aria-current="true"] {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #fff;
  font-weight: 600;
}

main { padding-bottom: 64px; }

.hero {
  padding: 40px 0 8px;
  text-align: center;
}

.hero h1 {
  font-size: clamp(1.6rem, 3.2vw, 2.4rem);
  margin: 0 0 10px;
  letter-spacing: -0.02em;
}

.hero p.lede {
  color: var(--color-text-muted);
  max-width: 640px;
  margin: 0 auto;
  font-size: 1.05rem;
}

.calc-grid {
  display: grid;
  grid-template-columns: minmax(280px, 380px) 1fr;
  gap: 24px;
  margin-top: 32px;
  align-items: start;
}

@media (max-width: 780px) {
  .calc-grid { grid-template-columns: 1fr; }
}

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
  padding: 24px;
}

.card h2, .card h3 { margin-top: 0; }

.field {
  margin-bottom: 18px;
}

.field label {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--color-text-muted);
  margin-bottom: 6px;
}

.field label .hint {
  font-weight: 400;
  font-size: 0.78rem;
  color: var(--color-text-muted);
  opacity: 0.8;
}

.field input[type="number"],
.field select {
  width: 100%;
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid var(--color-border);
  background: var(--color-bg);
  color: var(--color-text);
  font-size: 1rem;
  font-family: inherit;
}

.field input[type="number"]:focus,
.field select:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 1px;
}

.field-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.input-prefix, .input-suffix {
  position: relative;
}

.field .input-prefix input[type="number"] { padding-left: 32px; }
.input-prefix::before {
  content: attr(data-prefix);
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--color-text-muted);
  pointer-events: none;
}

.field .input-suffix input[type="number"] { padding-right: 40px; }
.input-suffix::after {
  content: attr(data-suffix);
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--color-text-muted);
  pointer-events: none;
}

.results-summary {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 14px;
  margin-bottom: 20px;
}

.stat {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: 14px 16px;
}

.stat .label {
  font-size: 0.78rem;
  color: var(--color-text-muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.stat .value {
  font-size: 1.35rem;
  font-weight: 700;
  margin-top: 4px;
}

.stat.accent .value { color: var(--color-accent); }
.stat.primary .value { color: var(--color-primary); }

.chart-box {
  position: relative;
  height: 320px;
  margin-top: 8px;
}

.legend-note {
  display: flex;
  gap: 18px;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-top: 10px;
  flex-wrap: wrap;
}

.legend-dot {
  display: inline-block;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  margin-right: 6px;
  vertical-align: middle;
}

table.breakdown {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
  margin-top: 12px;
}

table.breakdown th, table.breakdown td {
  padding: 8px 10px;
  text-align: right;
  border-bottom: 1px solid var(--color-border);
}

table.breakdown th:first-child, table.breakdown td:first-child { text-align: left; }

table.breakdown thead th {
  color: var(--color-text-muted);
  font-weight: 600;
  font-size: 0.78rem;
  text-transform: uppercase;
}

.table-scroll {
  max-height: 320px;
  overflow-y: auto;
  border: 1px solid var(--color-border);
  border-radius: 10px;
  padding: 0 12px;
}

details.breakdown-toggle summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--color-primary);
  margin-top: 16px;
}

section.content {
  margin-top: 56px;
}

section.content h2 {
  font-size: 1.5rem;
  margin-bottom: 10px;
}

section.content .card + .card { margin-top: 16px; }

.formula {
  background: var(--color-bg);
  border: 1px dashed var(--color-border);
  border-radius: 10px;
  padding: 14px 16px;
  font-family: "SFMono-Regular", Consolas, Menlo, monospace;
  font-size: 0.92rem;
  overflow-x: auto;
}

.faq-item summary {
  cursor: pointer;
  font-weight: 600;
  padding: 12px 0;
  list-style: none;
}

.faq-item summary::-webkit-details-marker { display: none; }

.faq-item summary::before {
  content: "+";
  display: inline-block;
  width: 18px;
  color: var(--color-primary);
  font-weight: 700;
}

.faq-item[open] summary::before { content: "\2212"; }

.faq-item p { margin: 0 0 14px 26px; color: var(--color-text-muted); }

.faq-item + .faq-item { border-top: 1px solid var(--color-border); }

.disclaimer {
  font-size: 0.82rem;
  color: var(--color-text-muted);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  padding: 14px 16px;
  margin-top: 24px;
}

footer.site-footer {
  border-top: 1px solid var(--color-border);
  padding: 28px 0 40px;
  color: var(--color-text-muted);
  font-size: 0.85rem;
  text-align: center;
}

footer.site-footer a { color: var(--color-text-muted); text-decoration: underline; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background: var(--color-primary);
  color: #fff;
  border: none;
  border-radius: 10px;
  padding: 12px 20px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  width: 100%;
  transition: background 0.15s ease;
}

.btn:hover { background: var(--color-primary-dark); }

.skip-link {
  position: absolute;
  left: -9999px;
  top: auto;
}

.skip-link:focus {
  position: fixed;
  left: 12px;
  top: 12px;
  background: var(--color-surface);
  padding: 10px 14px;
  border-radius: 8px;
  z-index: 999;
}