/* ── AMP → Bitcoin  v1.0 — Style pass ── */

/* ── Tokens ── */
:root {
  /* Colors */
  --bg: #0F1419;
  --panel: rgba(255,255,255,0.03);
  --text: rgba(255,255,255,0.92);
  --muted: rgba(255,255,255,0.70);
  --faint: rgba(255,255,255,0.55);
  --hairline: rgba(255,255,255,0.10);
  --hairline2: rgba(255,255,255,0.06);
  --accent: #6CB6FF;
  --accent2: rgba(108,182,255,0.20);
  --error: #f87171;

  /* Typography */
  --font: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  --mono: ui-monospace, 'SF Mono', 'Fira Mono', 'Roboto Mono', Menlo, Consolas, monospace;

  /* Type scale */
  --fs-xs: clamp(12px, 0.85vw, 13px);
  --fs-sm: clamp(14px, 1vw, 15px);
  --fs-md: clamp(15px, 1.15vw, 16px);
  --fs-lg: clamp(18px, 1.5vw, 20px);
  --fs-xl: clamp(28px, 2.5vw, 34px);
  --fs-hero: clamp(56px, 5.5vw, 80px);

  /* Spacing */
  --s-1: 6px;
  --s-2: 10px;
  --s-3: 14px;
  --s-4: 18px;
  --s-5: 24px;
  --s-6: 32px;
  --s-7: 44px;

  /* Radii */
  --r-1: 10px;
  --r-2: 14px;
}

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

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font);
  background: #161D25;
  color: var(--text);
  line-height: 1.5;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ── Layout ── */
main {
  width: 100%;
  max-width: 700px;
  margin: var(--s-6) auto;
  padding: var(--s-7) var(--s-6) var(--s-6);
  flex: 1;
  background: var(--bg);
  border: 1px solid var(--hairline);
  border-radius: var(--r-2);
}

/* ── Header ── */
.site-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--s-4);
  flex-wrap: wrap;
  margin-bottom: var(--s-6);
}

.site-title {
  font-size: var(--fs-md);
  font-weight: 500;
  color: var(--muted);
  letter-spacing: 0.01em;
  white-space: nowrap;
}

.site-title .arrow {
  color: var(--accent);
  opacity: 0.8;
  margin: 0 0.05em;
}

/* ── Unit toggle ── */
.unit-toggle {
  font-size: var(--fs-xs);
  color: var(--faint);
  display: flex;
  align-items: center;
  gap: var(--s-1);
}

.unit-toggle select {
  font-family: var(--font);
  font-size: var(--fs-xs);
  background: var(--panel);
  color: var(--muted);
  border: 1px solid var(--hairline);
  border-radius: var(--r-1);
  padding: 0.25em 0.5em;
  cursor: pointer;
  outline: none;
  transition: border-color 0.15s;
}

.unit-toggle select:focus-visible {
  outline: 1px solid var(--accent2);
  outline-offset: 1px;
}

/* ── Framing ── */
.framing {
  text-align: center;
  color: var(--muted);
  font-size: var(--fs-md);
  line-height: 1.45;
  max-width: 520px;
  margin: 0 auto var(--s-6);
}

.framing-sub {
  text-align: center;
  color: var(--faint);
  font-size: var(--fs-sm);
  line-height: 1.45;
  max-width: 520px;
  margin: calc(-1 * var(--s-4)) auto var(--s-6);
}

/* ── Input block ── */
.input-block {
  text-align: center;
  margin-bottom: var(--s-6);
}

.input-label {
  display: block;
  font-size: var(--fs-md);
  color: var(--muted);
  letter-spacing: 0.02em;
  margin-bottom: var(--s-3);
}

.input-field {
  display: inline-block;
  width: 100%;
  max-width: 320px;
  font-family: var(--font);
  font-size: var(--fs-xl);
  font-variant-numeric: tabular-nums;
  color: var(--text);
  background: transparent;
  border: none;
  border-bottom: 1.5px solid var(--hairline);
  padding: 0.25em 0.15em;
  text-align: center;
  outline: none;
  transition: border-color 0.2s, background-color 0.2s;
  -moz-appearance: textfield;
}

.input-field::-webkit-outer-spin-button,
.input-field::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.input-field::placeholder {
  color: var(--faint);
  opacity: 0.6;
}

.input-field:focus {
  border-bottom-color: var(--accent);
  background: rgba(108,182,255,0.06);
}

.helper {
  font-size: var(--fs-sm);
  color: var(--faint);
  margin-top: var(--s-2);
}

.error-msg {
  font-size: var(--fs-sm);
  color: var(--error);
  margin-top: var(--s-1);
  min-height: 1.3em;
}

/* ── Output container ── */
.output-container {
  text-align: center;
  margin-bottom: var(--s-6);
  transition: opacity 100ms ease;
}

.output-container.fading {
  opacity: 0.6;
}

.output-container.loading {
  opacity: 0.5;
  animation: pulse-loading 1.2s ease-in-out infinite;
}

@keyframes pulse-loading {
  0%, 100% { opacity: 0.5; }
  50% { opacity: 0.35; }
}

/* ── Hero number ── */
.hero-number {
  font-family: var(--font);
  font-size: var(--fs-hero);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.02em;
  line-height: 1.1;
  min-height: 1.1em;
  color: var(--text);
}

.hero-number .unit-label {
  font-size: var(--fs-lg);
  font-weight: 400;
  color: var(--muted);
  margin-left: 0.25em;
  letter-spacing: 0;
  vertical-align: baseline;
}

/* ── Secondary lines ── */
.secondary-lines {
  margin-top: var(--s-1);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
}

.secondary-lines > span {
  font-size: var(--fs-sm);
  color: rgba(255,255,255,0.48);
  font-variant-numeric: tabular-nums;
}

/* ── Secondary output (AI) ── */
.secondary-output {
  margin-top: var(--s-3);
  text-align: center;
  font-size: var(--fs-md);
  color: var(--muted);
}

.secondary-output > span {
  font-variant-numeric: tabular-nums;
}

/* ── Tooltips ── */
.tip-wrap {
  position: relative;
  display: inline-block;
}

.tip-trigger {
  font-family: var(--font);
  font-size: var(--fs-xs);
  color: var(--faint);
  background: none;
  border: none;
  cursor: pointer;
  padding: 0 0.2em;
  line-height: 1;
  vertical-align: middle;
  border-radius: 50%;
  outline: none;
  transition: color 0.15s;
}

.tip-trigger:hover,
.tip-trigger:focus-visible {
  color: var(--accent);
}

.tip-trigger:focus-visible {
  outline: 2px solid var(--accent2);
  outline-offset: 2px;
}

.tip-body {
  display: none;
  position: absolute;
  bottom: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%);
  width: max-content;
  max-width: 280px;
  background: rgba(0,0,0,0.82);
  color: var(--text);
  font-size: var(--fs-sm);
  line-height: 1.45;
  padding: var(--s-2) 12px;
  border-radius: var(--r-1);
  z-index: 100;
  pointer-events: none;
}

.tip-body::after {
  content: '';
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border: 5px solid transparent;
  border-top-color: rgba(0,0,0,0.82);
}

.tip-wrap:hover .tip-body,
.tip-trigger:focus + .tip-body,
.tip-body.visible {
  display: block;
}

/* ── Divider ── */
.divider {
  border: none;
  border-top: 1px solid var(--hairline2);
  margin: var(--s-4) 0;
}

/* ── Accordions ── */
.accordions {
  margin-bottom: var(--s-6);
}

.accordion {
  border-bottom: 1px solid var(--hairline2);
}

.accordion:first-child {
  border-top: 1px solid var(--hairline2);
}

.accordion summary {
  font-size: var(--fs-md);
  font-weight: 500;
  color: var(--muted);
  padding: var(--s-3) 0;
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  outline: none;
  user-select: none;
  transition: color 0.15s;
}

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

/* Chevron */
.accordion summary::after {
  content: '';
  display: inline-block;
  width: 8px;
  height: 8px;
  border-right: 1.5px solid var(--faint);
  border-bottom: 1.5px solid var(--faint);
  transform: rotate(45deg);
  transition: transform 150ms ease;
  flex-shrink: 0;
  margin-left: var(--s-3);
}

.accordion[open] summary::after {
  transform: rotate(-135deg);
}

.accordion summary:hover {
  color: var(--text);
}

.accordion summary:focus-visible {
  color: var(--accent);
  outline: 2px solid var(--accent2);
  outline-offset: 2px;
}

.accordion-body {
  font-size: var(--fs-sm);
  color: var(--muted);
  padding: 0 0 var(--s-4);
  line-height: 1.6;
}

.accordion-body p {
  margin-bottom: var(--s-1);
}

.accordion-prose p {
  margin-bottom: var(--s-4);
}

.accordion-prose p:last-child {
  margin-bottom: 0;
}

.accordion-body ul {
  padding-left: 1.2em;
}

.accordion-body li {
  margin-bottom: var(--s-1);
  color: var(--muted);
}

.accordion-body code {
  font-family: var(--mono);
  font-size: var(--fs-xs);
  background: rgba(255,255,255,0.06);
  padding: 0.15em 0.4em;
  border-radius: 4px;
}

.api-base {
  word-break: break-all;
}

pre.api-example {
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--hairline);
  border-radius: var(--r-1);
  padding: var(--s-3);
  overflow-x: auto;
  margin: var(--s-2) 0 var(--s-4);
}

pre.api-example code {
  background: none;
  padding: 0;
  white-space: pre-wrap;
  word-break: break-all;
}

.accordion-body .detail-value {
  color: var(--text);
  font-family: var(--mono);
  font-size: var(--fs-xs);
  font-variant-numeric: tabular-nums;
}

/* ── Country selector ── */
.country-row {
  margin-top: var(--s-3);
  padding-top: var(--s-3);
  border-top: 1px solid var(--hairline2);
}

.country-row label {
  font-size: var(--fs-xs);
  color: var(--faint);
  margin-right: var(--s-1);
}

.country-row select {
  font-family: var(--font);
  font-size: var(--fs-xs);
  background: var(--panel);
  color: var(--muted);
  border: 1px solid var(--hairline);
  border-radius: var(--r-1);
  padding: 0.25em 0.5em;
  cursor: pointer;
  outline: none;
  margin-bottom: var(--s-2);
  transition: border-color 0.15s;
}

.country-row select:focus-visible {
  outline: 1px solid var(--accent2);
  outline-offset: 1px;
}

/* ── Footer ── */
.site-footer {
  text-align: center;
  padding: var(--s-4) var(--s-5) var(--s-5);
  font-size: var(--fs-xs);
  color: var(--faint);
  max-width: 700px;
  margin: 0 auto;
}

.site-footer nav {
  display: flex;
  justify-content: center;
  gap: var(--s-5);
  margin-bottom: var(--s-1);
}

.site-footer a {
  color: var(--faint);
  text-decoration: none;
  transition: color 0.15s;
}

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

.site-footer a:focus-visible {
  color: var(--accent);
  outline: 2px solid var(--accent2);
  outline-offset: 2px;
}

.site-footer .meta {
  color: var(--faint);
}

/* ── Placeholder / empty state ── */
.output-container.empty .hero-number {
  visibility: hidden;
}

.output-container.empty .secondary-lines,
.output-container.empty .secondary-output {
  visibility: hidden;
}

/* ── Focus rings (global) ── */
:focus-visible {
  outline: 2px solid var(--accent2);
  outline-offset: 2px;
}

/* Override for elements with their own focus styles */
.input-field:focus-visible,
.tip-trigger:focus-visible,
.accordion summary:focus-visible,
.unit-toggle select:focus-visible,
.country-row select:focus-visible {
  outline: none;
}

/* Re-apply specific focus styles (already defined above per-element) */
.input-field:focus-visible {
  border-bottom-color: var(--accent);
  background: rgba(108,182,255,0.06);
}

.tip-trigger:focus-visible {
  outline: 2px solid var(--accent2);
  outline-offset: 2px;
}

.accordion summary:focus-visible {
  outline: 2px solid var(--accent2);
  outline-offset: 2px;
}

.unit-toggle select:focus-visible {
  outline: 1px solid var(--accent2);
  outline-offset: 1px;
}

.country-row select:focus-visible {
  outline: 1px solid var(--accent2);
  outline-offset: 1px;
}

/* ── Responsive ── */
@media (max-width: 480px) {
  main {
    padding: var(--s-6) var(--s-4) var(--s-5);
  }

  .site-header {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--s-2);
  }

  .input-field {
    max-width: 280px;
  }

  .tip-body {
    max-width: 240px;
    left: auto;
    right: -8px;
    transform: none;
  }

  .tip-body::after {
    left: auto;
    right: 14px;
    transform: none;
  }
}

/* ── Safe area ── */
@supports (padding: env(safe-area-inset-bottom)) {
  .site-footer {
    padding-bottom: calc(var(--s-5) + env(safe-area-inset-bottom));
  }
}