/* Reset & Document Baseline */
*, *::before, *::after {
  box-sizing: border-box;
}

html {
  font-synthesis: none;
  letter-spacing: 0;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: auto;
}

body {
  margin: 0;
  padding: 0;
  background-color: var(--color-neutral);
  color: var(--color-ink);
  font: var(--type-body);
  font-synthesis: none;
  letter-spacing: 0;
}

/* Accessibility: Skip Link */
.skip-link {
  position: absolute;
  top: -100px;
  left: var(--gutter);
  background: var(--color-primary);
  color: var(--color-on-primary);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-control);
  font: var(--type-body-strong);
  text-decoration: none;
  z-index: 1000;
  transition: top 120ms ease-out;
}

.skip-link:focus-visible {
  top: var(--space-md);
  outline: 2px solid var(--color-ink);
  outline-offset: 2px;
}

/* Accessible Focus Ring */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* Typography Defaults */
/* Keep each Thai phrase whole; wrap only at the space between phrases. */
.phrase { display: inline-block; }

h1 {
  font: var(--type-display);
  color: var(--color-ink);
  margin-block: 0 var(--space-md);
  text-wrap: balance;
}

h2 {
  font: var(--type-headline);
  color: var(--color-ink);
  margin-block: 0 var(--space-md);
  text-wrap: balance;
}

h3 {
  font: var(--type-title);
  color: var(--color-ink);
  margin-block: 0 var(--space-sm);
  text-wrap: balance;
}

p {
  margin-block: 0 var(--space-md);
  text-wrap: pretty;
  max-width: var(--text-measure);
}

a {
  color: var(--color-primary);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

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

kbd {
  font-family: var(--font-display);
  background-color: var(--color-keycap);
  border: 1px solid var(--color-rule);
  border-bottom: 2px solid var(--color-keycap-edge);
  border-radius: var(--radius-control);
  padding: 1px 6px;
  font-size: 0.9em;
  line-height: 1.3;
  color: var(--color-ink);
  display: inline-block;
  vertical-align: baseline;
}

mark {
  background-color: var(--color-highlight);
  color: var(--color-ink);
  padding: 0 4px;
  border-radius: var(--radius-control);
}

/* Page Layout */
.page-container {
  max-width: var(--page-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.site-section {
  margin-block-end: var(--space-section);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font: var(--type-body-strong);
  padding: 14px 24px;
  min-height: 44px;
  border-radius: var(--radius-key);
  cursor: pointer;
  text-decoration: none;
  font-synthesis: none;
  border: 1px solid transparent;
  border-bottom: var(--key-edge) solid var(--color-keycap-edge);
  transition: transform 80ms cubic-bezier(0.2, 0.8, 0.2, 1),
              border-bottom-width 80ms cubic-bezier(0.2, 0.8, 0.2, 1),
              margin-bottom 80ms cubic-bezier(0.2, 0.8, 0.2, 1),
              background-color 80ms cubic-bezier(0.2, 0.8, 0.2, 1);
  box-sizing: border-box;
}

.btn:active {
  transform: translateY(2px);
  border-bottom-width: var(--key-edge-pressed);
  margin-bottom: 2px;
}

.btn-primary {
  background-color: var(--color-primary);
  color: var(--color-on-primary);
  border-color: var(--color-primary);
  border-bottom-color: var(--color-primary-pressed);
}

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

.btn-secondary {
  background-color: var(--color-keycap);
  color: var(--color-ink);
  border-color: var(--color-rule);
  border-bottom-color: var(--color-keycap-edge);
}

.btn-secondary:hover {
  background-color: var(--color-neutral);
  color: var(--color-ink);
}

.btn-sm {
  padding: 8px 16px;
  min-height: 38px;
  font-size: 0.9375rem;
}

/* Header */
.site-header {
  padding-block: var(--space-lg);
  margin-block-end: var(--space-xl);
}

.site-header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
}

.wordmark-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  text-decoration: none;
  color: var(--color-ink);
}

.wordmark-icon {
  display: block;
  width: 26px;
  height: 26px;
  flex-shrink: 0;
}

.wordmark-text {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1;
  color: var(--color-ink);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.nav-link {
  font: var(--type-body-strong);
  color: var(--color-ink);
  text-decoration: none;
  padding: var(--space-xs) var(--space-xs);
  min-height: 44px;
  display: inline-flex;
  align-items: center;
}

.nav-link:hover {
  color: var(--color-primary);
}

@media (max-width: 640px) {
  .nav-link-desktop {
    display: none;
  }
}

/* Hero Section */
.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-xl);
  align-items: flex-start;
}

@media (max-width: 860px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: var(--space-xl);
  }
}

.hero-lead {
  font: var(--type-body);
  font-size: 1.1875rem;
  color: var(--color-ink);
  margin-block-end: var(--space-lg);
}

.hero-actions {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  flex-wrap: wrap;
  margin-block-end: var(--space-md);
}

.hero-link-video {
  font: var(--type-body-strong);
  color: var(--color-primary);
  text-decoration: none;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  padding: var(--space-xs) var(--space-sm);
}

.hero-link-video:hover {
  text-decoration: underline;
}

.hero-meta {
  font: var(--type-small);
  color: var(--color-slate);
  margin: 0;
}

/* Hero Right Column: Keycaps & Demo */
.hero-demo-stage {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.keycap-row {
  display: flex;
  gap: var(--space-sm);
  perspective: 600px;
  flex-wrap: nowrap;
  overflow-x: auto;
  padding-bottom: 6px;
  min-height: var(--key-size);
}

.keycap {
  width: var(--key-size);
  height: var(--key-size);
  position: relative;
  flex-shrink: 0;
}

.keycap-inner {
  width: 100%;
  height: 100%;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 380ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

.keycap.is-flipped .keycap-inner {
  transform: rotateX(-180deg);
}

.keycap-face {
  position: absolute;
  inset: 0;
  background-color: var(--color-keycap);
  border: 1px solid var(--color-rule);
  border-bottom: var(--key-edge) solid var(--color-keycap-edge);
  border-radius: var(--radius-key);
  box-sizing: border-box;
  padding: 3px 6px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  user-select: none;
}

.keycap-face-front {
  /* Front face orientation */
}

.keycap-face-back {
  transform: rotateX(180deg);
}

.legend-latin {
  align-self: flex-start;
  text-align: left;
}

.legend-thai {
  align-self: flex-end;
  text-align: right;
}

.legend-lead-ink {
  font-family: var(--font-display);
  font-size: clamp(1.125rem, 3.2vw, 1.375rem);
  font-weight: 600;
  line-height: 1.2;
  color: var(--color-ink);
}

.legend-lead-primary {
  font-family: var(--font-display);
  font-size: clamp(1.25rem, 3.8vw, 1.75rem);
  font-weight: 600;
  line-height: 1.35;
  color: var(--color-primary);
}

.legend-sub {
  font-family: var(--font-display);
  font-size: clamp(0.75rem, 2.2vw, 0.9375rem);
  font-weight: 500;
  line-height: 1.25;
  color: var(--color-slate);
}

.hero-result-line {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  min-height: 44px;
  margin: 0;
  flex-wrap: wrap;
}

.hero-result-caption {
  font: var(--type-small);
  color: var(--color-slate);
}

.composed-word {
  display: inline-block;
  background-color: var(--color-highlight);
  color: var(--color-ink);
  font: var(--type-title);
  padding: 2px 8px;
  border-radius: var(--radius-control);
  opacity: 0;
  transform: scale(0.98);
  transition: opacity 200ms cubic-bezier(0.2, 0.8, 0.2, 1),
              transform 200ms cubic-bezier(0.2, 0.8, 0.2, 1);
  word-break: normal;
}

.composed-word.is-visible {
  opacity: 1;
  transform: scale(1);
}

.demo-input-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  max-width: var(--text-measure);
}

.demo-input-label {
  font: var(--type-body-strong);
  color: var(--color-ink);
}

.demo-text-input {
  background-color: var(--color-keycap);
  color: var(--color-ink);
  font: var(--type-title);
  border-radius: var(--radius-control);
  padding: 16px 20px;
  border: 1px solid var(--color-rule);
  border-bottom: var(--key-edge) solid var(--color-keycap-edge);
  width: 100%;
  box-sizing: border-box;
  font-synthesis: none;
  min-height: 56px;
}

.demo-text-input::placeholder {
  color: var(--color-slate);
  opacity: 0.7;
}

.demo-input-note {
  font: var(--type-small);
  color: var(--color-slate);
  margin: 0;
}

/* Video Section */
.video-frame {
  background-color: var(--color-keycap);
  border: 1px solid var(--color-rule);
  border-radius: var(--radius-panel);
  overflow: hidden;
  aspect-ratio: 16 / 9;
  max-width: 100%;
  margin-block: var(--space-md) var(--space-md);
}

.video-frame video {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: cover;
  background-color: var(--color-keycap);
}

.video-captions-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-md);
  margin-top: var(--space-sm);
  max-width: var(--text-measure);
}

@media (max-width: 640px) {
  .video-captions-grid {
    grid-template-columns: 1fr;
  }
}

.video-caption-item {
  font: var(--type-small);
  color: var(--color-ink);
  display: flex;
  align-items: baseline;
  gap: var(--space-xs);
  flex-wrap: wrap;
}

.mini-key-pair {
  display: inline-flex;
  gap: 2px;
  vertical-align: middle;
}

.mini-key {
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 1px 4px;
  background-color: var(--color-keycap);
  border: 1px solid var(--color-rule);
  border-bottom: 2px solid var(--color-keycap-edge);
  border-radius: 4px;
  line-height: 1.2;
  color: var(--color-ink);
}

/* Comparison rows in Section 3 */
.compare-box {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  margin-block-start: var(--space-md);
  max-width: var(--text-measure);
}

.compare-row {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding-block: var(--space-xs);
  flex-wrap: wrap;
}

.compare-arrow {
  color: var(--color-slate);
  user-select: none;
}

.compare-status {
  font: var(--type-body-strong);
}

.text-slate {
  color: var(--color-slate);
}

.text-primary {
  color: var(--color-primary);
  font-weight: 600;
}

/* Chips in Section 4 */
.key-chip {
  font-family: var(--font-display);
  font-size: 0.875rem;
  font-weight: 600;
  padding: 2px 8px;
  background-color: var(--color-keycap);
  border: 1px solid var(--color-rule);
  border-bottom: 2px solid var(--color-keycap-edge);
  border-radius: var(--radius-control);
  color: var(--color-ink);
  display: inline-block;
  line-height: 1.3;
  vertical-align: middle;
}

/* Privacy Panel in Section 5 */
.privacy-panel {
  background-color: var(--color-keycap);
  border: 1px solid var(--color-rule);
  border-radius: var(--radius-panel);
  padding: var(--space-xl);
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
  max-width: var(--text-measure);
  margin-block-start: var(--space-md);
}

@media (max-width: 640px) {
  .privacy-panel {
    padding: var(--space-lg);
  }
}

.privacy-group h3 {
  margin-block: 0 var(--space-xs);
  font-size: 1.125rem;
}

.privacy-group ul {
  margin: 0;
  padding-left: 20px;
}

.privacy-group li {
  font: var(--type-body);
  margin-block: var(--space-xs);
}

.privacy-source-links {
  font: var(--type-small);
  color: var(--color-slate);
  margin-block-start: var(--space-md);
}

/* FAQ in Section 7 */
.faq-list {
  max-width: var(--text-measure);
  margin-block-start: var(--space-md);
}

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

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

.faq-question {
  font: var(--type-title);
  color: var(--color-ink);
  padding-block: var(--space-md);
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-md);
  user-select: none;
}

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

.faq-indicator {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 500;
  color: var(--color-slate);
  transition: transform 180ms ease-out;
  flex-shrink: 0;
}

details[open] .faq-indicator {
  transform: rotate(45deg);
}

.faq-answer {
  padding-bottom: var(--space-md);
}

.faq-answer p {
  margin: 0;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--color-rule);
  padding-block: var(--space-xl);
  margin-top: var(--space-section);
}

.site-footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-md);
}

.footer-meta {
  font: var(--type-small);
  color: var(--color-slate);
  margin: 0;
}

.footer-links {
  display: flex;
  gap: var(--space-md);
  flex-wrap: wrap;
}

.footer-links a {
  font: var(--type-small);
  color: var(--color-slate);
  text-decoration: none;
}

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

/* Reduced Motion Mode */
@media (prefers-reduced-motion: reduce) {
  .keycap-row {
    perspective: none;
  }
  .keycap-inner {
    transform: none !important;
    transition: none !important;
  }
  .keycap-face {
    transition: opacity 150ms ease-out !important;
  }
  .keycap-face-front {
    opacity: 1;
  }
  .keycap-face-back {
    transform: none !important;
    opacity: 0;
  }
  .keycap.is-flipped .keycap-face-front {
    opacity: 0;
  }
  .keycap.is-flipped .keycap-face-back {
    opacity: 1;
  }
  .composed-word {
    transform: none !important;
    transition: opacity 200ms ease-out !important;
  }
  .btn {
    transition: none !important;
  }
  .faq-indicator {
    transition: none !important;
  }
}

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

/* 404 page */
.not-found { padding-block: var(--space-section); }