/* ============================================================
   MarketViz — USD/VND Eximbank
   Light, document-flow layout. Green/red mean direction only;
   every piece of UI chrome is ink on paper.
   ============================================================ */

:root {
  --paper: #f7f7f3;          /* page plane */
  --panel: #fdfdfc;          /* chart stage surface */
  --ink: #1a1c18;            /* primary text */
  --ink-rgb: 26, 28, 24;     /* ink channels, for rgba() compositions */
  --ink-2: #4f544b;          /* secondary text */
  --ink-3: #6e7268;          /* muted: captions, axis labels */
  --hairline: #e4e5de;       /* section rules */
  --rule: #d3d6cc;           /* panel border, deeper rules */
  --grid: #ecede7;           /* chart gridlines */
  --axis: #d8dad1;           /* chart axis baseline */

  --up: #0e7c46;             /* rate up */
  --up-tint: rgba(14, 124, 70, 0.09);
  --down: #c33524;           /* rate down */
  --down-tint: rgba(195, 53, 36, 0.08);

  /* Buy/sell band — app.js mirrors these via computed style */
  --band-edge: #8a8e84;
  --band-fill: rgba(110, 114, 104, 0.14);

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  --radius: 10px;
  --radius-sm: 7px;
  --shadow-panel: 0 1px 2px rgba(var(--ink-rgb), 0.04),
    0 10px 28px -16px rgba(var(--ink-rgb), 0.12);
}

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

html {
  scroll-behavior: smooth;
}

body {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  padding: 28px 20px 40px;
}

.page {
  max-width: 1060px;
  margin: 0 auto;
}

.noscript {
  margin-bottom: 20px;
  padding: 12px 16px;
  border: 1px solid var(--rule);
  border-radius: var(--radius-sm);
  background: var(--panel);
  color: var(--ink-2);
  font-size: 14px;
}

/* Numbers stay tabular everywhere so digits align down a row */
.big-rate,
.stat-value,
.change-badge,
.delta,
.hero-rates strong {
  font-variant-numeric: tabular-nums;
}

:focus-visible {
  outline: 2px solid var(--ink);
  outline-offset: 2px;
  border-radius: 2px;
}

/* ============================================================
   Masthead
   ============================================================ */

.masthead {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: 16px;
  flex-wrap: wrap;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--hairline);
}

.masthead-title {
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.masthead-org {
  font-weight: 500;
  color: var(--ink-2);
}

.masthead-note {
  margin-top: 2px;
  font-size: 13px;
  color: var(--ink-3);
}

.masthead-updated {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--ink-2);
  white-space: nowrap;
}

.live-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--up);
  animation: pulse 2.4s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.45; }
}

/* ============================================================
   Hero — current state
   ============================================================ */

.hero {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: 40px;
  padding: 34px 0 30px;
}

.hero-label {
  font-size: 13px;
  color: var(--ink-2);
  margin-bottom: 6px;
}

.hero-figure {
  display: flex;
  align-items: baseline;
  gap: 14px;
  flex-wrap: wrap;
}

.big-rate {
  font-size: clamp(52px, 8vw, 74px);
  font-weight: 650;
  letter-spacing: -0.025em;
  line-height: 1.05;
}

.hero-unit {
  font-size: 22px;
  font-weight: 500;
  color: var(--ink-3);
}

.change-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 5px 12px;
  border-radius: 999px;
  font-size: 14.5px;
  font-weight: 600;
  line-height: 1.2;
  white-space: nowrap;
}

.change-badge.positive {
  background: var(--up-tint);
  color: var(--up);
}

.change-badge.negative {
  background: var(--down-tint);
  color: var(--down);
}

.change-badge.neutral {
  background: rgba(var(--ink-rgb), 0.06);
  color: var(--ink-2);
}

.hero-rates {
  margin-top: 14px;
  font-size: 15px;
  color: var(--ink-2);
}

.hero-rates strong {
  font-weight: 600;
  color: var(--ink);
}

.sep {
  margin: 0 6px;
  color: var(--ink-3);
}

/* Fixed landmark deltas, independent of the selected range */
.hero-vs {
  min-width: 248px;
}

.hero-vs-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 24px;
  padding: 9px 0;
  border-top: 1px solid var(--hairline);
}

.hero-vs-row:last-child {
  border-bottom: 1px solid var(--hairline);
}

.hero-vs dt {
  font-size: 13px;
  color: var(--ink-2);
}

.delta {
  font-size: 14.5px;
  font-weight: 600;
  white-space: nowrap;
}

.delta.pos { color: var(--up); }
.delta.neg { color: var(--down); }
.delta.neutral { color: var(--ink-2); }

/* ============================================================
   Controls — one row above everything it scopes
   ============================================================ */

.controls {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  padding: 6px 0 22px;
}

.range-switcher {
  display: inline-flex;
  gap: 2px;
  padding: 3px;
  background: var(--panel);
  border: 1px solid var(--rule);
  border-radius: var(--radius-sm);
}

.range-tab {
  appearance: none;
  border: none;
  background: transparent;
  font-family: inherit;
  font-size: 13.5px;
  font-weight: 600;
  color: var(--ink-2);
  padding: 6px 16px;
  border-radius: 5px;
  cursor: pointer;
  transition: background-color 0.12s ease, color 0.12s ease;
}

.range-tab:hover {
  color: var(--ink);
  background: rgba(var(--ink-rgb), 0.05);
}

.range-tab.active {
  background: var(--ink);
  color: var(--paper);
}

.band-toggle {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  user-select: none;
  font-size: 13.5px;
  color: var(--ink-2);
}

.band-toggle:hover .band-toggle-text { color: var(--ink); }

.band-toggle input {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
}

.band-toggle-track {
  position: relative;
  width: 34px;
  height: 20px;
  border-radius: 999px;
  background: rgba(var(--ink-rgb), 0.12);
  transition: background-color 0.15s ease;
  flex: none;
}

.band-toggle-track::before {
  content: "";
  position: absolute;
  top: 3px;
  left: 3px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--panel);
  box-shadow: 0 1px 2px rgba(var(--ink-rgb), 0.25);
  transition: transform 0.15s ease;
}

.band-toggle input:checked + .band-toggle-track {
  background: var(--ink);
}

.band-toggle input:checked + .band-toggle-track::before {
  transform: translateX(14px);
}

.band-toggle input:focus-visible + .band-toggle-track {
  outline: 2px solid var(--ink);
  outline-offset: 2px;
}

/* ============================================================
   Period stats
   ============================================================ */

.period-stats {
  padding: 4px 0 26px;
}

.period-stats-head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 14px;
}

.stat-range {
  font-size: 14.5px;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.stat-days {
  font-size: 13px;
  color: var(--ink-3);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
}

.stat-cell {
  padding: 4px 18px 4px 20px;
  border-left: 1px solid var(--hairline);
  min-width: 0;
}

.stat-cell:first-child {
  border-left: none;
  padding-left: 0;
}

.stat-cell dt {
  font-size: 12.5px;
  color: var(--ink-2);
  margin-bottom: 4px;
}

.stat-value {
  font-size: 20px;
  font-weight: 650;
  letter-spacing: -0.01em;
  white-space: nowrap;
}

.stat-value.pos { color: var(--up); }
.stat-value.neg { color: var(--down); }

.stat-sub {
  margin-top: 3px;
  font-size: 12px;
  color: var(--ink-3);
  white-space: nowrap;
}

/* ============================================================
   Chart stage — the single framed panel on the page
   ============================================================ */

.chart-stage {
  position: relative;
  background: var(--panel);
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  box-shadow: var(--shadow-panel);
  padding: 18px 22px 14px;
}

.chart-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 6px;
}

.chart-title {
  font-size: 15px;
  font-weight: 650;
  letter-spacing: -0.005em;
}

.chart-legend {
  display: inline-flex;
  align-items: center;
  gap: 18px;
  font-size: 12.5px;
  color: var(--ink-2);
}

.legend-chip {
  display: inline-flex;
  align-items: center;
  gap: 7px;
}

.legend-key-mid {
  width: 16px;
  height: 3px;
  border-radius: 2px;
  background: var(--ink-3);
}

.legend-key-band {
  width: 16px;
  height: 10px;
  border-radius: 3px;
  background: var(--band-fill);
  border-top: 1px solid var(--band-edge);
  border-bottom: 1px solid var(--band-edge);
}

.chart-wrap {
  position: relative;
}

.chart-container {
  width: 100%;
  height: 440px;
  min-height: 300px;
}

/* ============================================================
   Overlay: loading & error
   ============================================================ */

.overlay-message {
  position: absolute;
  inset: 0;
  z-index: 5;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 14px;
  border-radius: var(--radius);
  background: rgba(253, 253, 252, 0.92);
}

.overlay-text {
  color: var(--ink-2);
  font-size: 14px;
}

.spinner {
  width: 30px;
  height: 30px;
  border: 3px solid var(--hairline);
  border-top-color: var(--ink-2);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ============================================================
   Footer
   ============================================================ */

.site-footer {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 26px;
  padding-top: 16px;
  border-top: 1px solid var(--hairline);
  font-size: 12.5px;
  color: var(--ink-3);
}

.footer-link {
  color: var(--ink-2);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-color: var(--rule);
}

.footer-link:hover {
  color: var(--ink);
  text-decoration-color: var(--ink);
}

/* ============================================================
   Responsive
   ============================================================ */

@media (max-width: 920px) {
  .hero {
    grid-template-columns: 1fr;
    gap: 22px;
    padding: 28px 0 24px;
  }

  .hero-vs {
    min-width: 0;
    width: 100%;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
  }

  .hero-vs-row {
    display: block;
    border-top: none;
    border-bottom: none;
    padding: 10px 0 0;
    border-top: 1px solid var(--hairline);
  }

  .hero-vs dt {
    margin-bottom: 2px;
  }

  .stats-grid {
    grid-template-columns: repeat(3, 1fr);
    row-gap: 18px;
  }

  .stat-cell {
    padding: 0 12px 0 16px;
  }

  .stat-cell:nth-child(3n + 1) {
    border-left: none;
    padding-left: 0;
  }

  .chart-container {
    height: 380px;
  }
}

@media (max-width: 600px) {
  body {
    padding: 20px 14px 32px;
  }

  .masthead {
    align-items: flex-start;
    flex-direction: column;
    gap: 8px;
  }

  .big-rate {
    font-size: 46px;
  }

  .change-badge {
    font-size: 13.5px;
  }

  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
    row-gap: 16px;
  }

  .stat-cell {
    border-left: none;
    padding: 12px 0 0;
    border-top: 1px solid var(--hairline);
  }

  .controls {
    align-items: stretch;
    flex-direction: column;
    gap: 12px;
  }

  .range-switcher {
    display: flex;
  }

  .range-tab {
    flex: 1;
    padding: 7px 4px;
    text-align: center;
  }

  .chart-stage {
    padding: 14px 10px 10px;
  }

  .chart-container {
    height: 320px;
  }
}

/* ============================================================
   Reduced motion
   ============================================================ */

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .live-dot,
  .spinner {
    animation: none;
  }

  .range-tab,
  .band-toggle-track,
  .band-toggle-track::before {
    transition: none;
  }
}