:root {
  --bg: #0f1419;
  --surface: #1a222c;
  --surface-2: #243040;
  --border: #2e3a4a;
  --text: #e8eef5;
  --muted: #8b9bb0;
  --accent: #3d9cf0;
  --accent-soft: rgba(61, 156, 240, 0.15);
  --ok: #3ecf8e;
  --radius: 12px;
  --font: "Segoe UI", system-ui, -apple-system, "PingFang SC", "Noto Sans SC", "Microsoft YaHei", sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
}

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

html {
  color-scheme: dark;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font);
  background: radial-gradient(1200px 600px at 10% -10%, #1a3050 0%, transparent 55%),
    radial-gradient(900px 500px at 100% 0%, #152838 0%, transparent 50%),
    var(--bg);
  color: var(--text);
  line-height: 1.55;
}

.wrap {
  width: min(860px, calc(100% - 2rem));
  margin-inline: auto;
}

.site-header {
  padding: 2.25rem 0 1rem;
}

.site-header h1 {
  margin: 0;
  font-size: clamp(1.6rem, 4vw, 2rem);
  letter-spacing: -0.02em;
}

.subtitle {
  margin: 0.35rem 0 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.header-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
}

.header-text {
  min-width: 0;
}

.lang-switch {
  display: inline-flex;
  flex-shrink: 0;
  align-items: center;
}

.lang-select {
  appearance: none;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface)
    url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath fill='%238b9bb0' d='M1.4 1.4L6 6l4.6-4.6L12 2.8 6 8.8 0 2.8z'/%3E%3C/svg%3E")
    no-repeat right 0.85rem center / 10px;
  color: var(--text);
  font: inherit;
  font-size: 0.82rem;
  font-weight: 600;
  padding: 0.45rem 2rem 0.45rem 0.9rem;
  cursor: pointer;
  line-height: 1.2;
  max-width: 11.5rem;
}

.lang-select:hover,
.lang-select:focus {
  border-color: var(--accent);
  outline: none;
}

html[dir="rtl"] .lang-select {
  background-position: left 0.85rem center;
  padding: 0.45rem 0.9rem 0.45rem 2rem;
}

html[dir="rtl"] .breakdown {
  padding-left: 0;
  padding-right: 1.15rem;
}


main {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  padding-bottom: 3rem;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.1rem 1.2rem 1.25rem;
}

.card h2 {
  margin: 0 0 0.75rem;
  font-size: 1.05rem;
}

.card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-bottom: 0.65rem;
}

.card-head h2 {
  margin: 0;
}

.actions {
  display: flex;
  gap: 0.4rem;
}

.btn {
  appearance: none;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text);
  border-radius: 8px;
  padding: 0.35rem 0.75rem;
  font: inherit;
  font-size: 0.85rem;
  cursor: pointer;
}

.btn:hover {
  border-color: var(--accent);
}

.btn.ghost {
  background: transparent;
}

textarea {
  width: 100%;
  resize: vertical;
  min-height: 200px;
  padding: 0.9rem 1rem;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: #121820;
  color: var(--text);
  font: inherit;
  font-size: 0.95rem;
  line-height: 1.5;
}

textarea:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.privacy {
  margin: 0.65rem 0 0;
  font-size: 0.85rem;
  color: var(--ok);
}

.stats {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem;
}

@media (min-width: 640px) {
  .stats {
    grid-template-columns: repeat(4, 1fr);
  }
}

.stat {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.9rem 1rem;
}

.stat.primary {
  border-color: var(--accent);
  background: linear-gradient(160deg, var(--accent-soft), var(--surface));
}

.stat-label {
  font-size: 0.78rem;
  color: var(--muted);
  text-transform: none;
}

.stat-value {
  font-size: 1.65rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
  margin: 0.15rem 0;
}

.stat-hint {
  font-size: 0.72rem;
  color: var(--muted);
}

.breakdown {
  margin: 0;
  padding-left: 1.15rem;
  color: var(--muted);
}

.breakdown strong {
  color: var(--text);
  font-variant-numeric: tabular-nums;
}

.formulas {
  margin-top: 0.9rem;
  border-top: 1px solid var(--border);
  padding-top: 0.65rem;
}

.formulas summary {
  cursor: pointer;
  color: var(--accent);
  font-size: 0.9rem;
}

.formulas-body {
  margin-top: 0.6rem;
  font-size: 0.88rem;
  color: var(--muted);
}

.formulas-body code {
  font-family: var(--mono);
  font-size: 0.84em;
  background: var(--surface-2);
  padding: 0.1em 0.35em;
  border-radius: 4px;
  color: var(--text);
}

.muted {
  margin: 0 0 0.85rem;
  color: var(--muted);
  font-size: 0.88rem;
}

.en {
  color: var(--muted);
  font-weight: 500;
  font-size: 0.9em;
}

.cost-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.75rem;
}

@media (min-width: 560px) {
  .cost-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.cost-grid label {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  font-size: 0.82rem;
  color: var(--muted);
}

.cost-grid input {
  padding: 0.55rem 0.65rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: #121820;
  color: var(--text);
  font: inherit;
  font-variant-numeric: tabular-nums;
}

.cost-grid input:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.cost-results {
  margin-top: 1rem;
  padding: 0.85rem 1rem;
  background: var(--surface-2);
  border-radius: 10px;
  font-size: 0.92rem;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.cost-total {
  margin-top: 0.25rem;
  padding-top: 0.45rem;
  border-top: 1px solid var(--border);
  font-size: 1.05rem;
}

.faq h3 {
  margin: 1rem 0 0.35rem;
  font-size: 0.95rem;
}

.faq h3:first-of-type {
  margin-top: 0.25rem;
}

.faq p {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.site-footer {
  padding: 1.5rem 0 2.5rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.8rem;
}

.site-footer p {
  margin: 0;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* word-counter extras */
@media (min-width: 640px) {
  .stats.stats-5 {
    grid-template-columns: repeat(5, 1fr);
  }
}
.stats.stats-5 {
  grid-template-columns: repeat(2, 1fr);
}