:root {
  color-scheme: light;
  --ink: #202327;
  --muted: #667179;
  --paper: #f7fbf8;
  --surface: #ffffff;
  --line: #d8e1dc;
  --green: #176b52;
  --green-dark: #10513e;
  --green-soft: #e5f3ec;
  --red: #bd3d32;
  --gold: #d88f1f;
  --sky: #e3f1f6;
  --charcoal: #30363a;
  --shadow: 0 16px 42px rgba(29, 42, 38, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.5;
}

button,
input,
select {
  font: inherit;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

button:disabled {
  cursor: default;
  opacity: 0.78;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  min-height: 70px;
  padding: 12px 44px;
  background: rgba(247, 251, 248, 0.92);
  border-bottom: 1px solid rgba(216, 225, 220, 0.86);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
  color: inherit;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border-radius: 8px;
  background: var(--green);
  color: #fff;
  font-family: "Noto Sans Thai", Tahoma, sans-serif;
  font-size: 1.75rem;
  font-weight: 800;
}

.brand strong,
.brand small {
  display: block;
}

.brand strong {
  font-size: 0.98rem;
}

.brand small {
  color: var(--muted);
  font-size: 0.78rem;
  white-space: nowrap;
}

.nav {
  display: flex;
  align-items: center;
  gap: 6px;
}

.nav a {
  border-radius: 8px;
  color: var(--charcoal);
  padding: 8px 11px;
  text-decoration: none;
  white-space: nowrap;
}

.nav a:hover,
.nav a:focus-visible {
  background: var(--green-soft);
  outline: none;
}

main {
  overflow: hidden;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(320px, 1.05fr);
  gap: 48px;
  align-items: center;
  padding: 58px 44px 34px;
}

.hero-copy {
  max-width: 720px;
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--red);
  font-size: 0.78rem;
  font-weight: 800;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  overflow-wrap: anywhere;
}

h1 {
  margin: 0;
  color: var(--charcoal);
  font-size: 4.8rem;
  line-height: 0.94;
  letter-spacing: 0;
  overflow-wrap: normal;
  word-break: normal;
}

h2 {
  margin: 0;
  color: var(--charcoal);
  font-size: 2.35rem;
  line-height: 1.08;
  letter-spacing: 0;
}

h3 {
  margin: 0;
  letter-spacing: 0;
}

.hero-subtitle {
  max-width: 610px;
  margin: 22px 0 0;
  color: var(--muted);
  font-size: 1.12rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.primary-action,
.secondary-action,
.button-reset,
.icon-button,
.play-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  border-radius: 8px;
  cursor: pointer;
  text-decoration: none;
}

.primary-action {
  gap: 10px;
  border: 0;
  background: var(--green);
  color: #fff;
  padding: 0 18px;
  box-shadow: 0 12px 24px rgba(23, 107, 82, 0.22);
}

.primary-action:hover,
.primary-action:focus-visible {
  background: var(--green-dark);
  outline: none;
}

.secondary-action,
.button-reset {
  border: 1px solid var(--line);
  background: #fff;
  color: var(--charcoal);
  padding: 0 16px;
}

.secondary-action:hover,
.secondary-action:focus-visible,
.button-reset:hover,
.button-reset:focus-visible {
  border-color: var(--green);
  outline: none;
}

.stats {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 24px;
}

.stats span {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 34px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--muted);
  padding: 0 12px;
}

.stats strong {
  color: var(--green);
}

.hero-media {
  margin: 0;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  box-shadow: var(--shadow);
  overflow: hidden;
}

.hero-media img {
  display: block;
  width: 100%;
  aspect-ratio: 1169 / 827;
  object-fit: cover;
}

.control-strip {
  display: grid;
  grid-template-columns: repeat(4, minmax(140px, 1fr)) auto auto;
  gap: 12px;
  align-items: end;
  margin: 0 44px 28px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.9);
  box-shadow: 0 12px 30px rgba(29, 42, 38, 0.08);
}

.control-strip > div {
  min-width: 0;
}

.control-label {
  display: block;
  margin-bottom: 6px;
  color: var(--muted);
  font-size: 0.76rem;
  font-weight: 800;
  text-transform: uppercase;
}

select,
input[type="search"] {
  width: 100%;
  min-height: 42px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
  padding: 0 12px;
}

input[type="range"] {
  width: 100%;
  accent-color: var(--green);
}

.icon-button,
.play-button {
  width: 44px;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--green);
  font-weight: 800;
}

.icon-button:hover,
.icon-button:focus-visible,
.play-button:hover,
.play-button:focus-visible {
  border-color: var(--green);
  background: var(--green-soft);
  outline: none;
}

.section {
  padding: 52px 44px;
}

.section-band {
  background: #edf6f2;
  border-block: 1px solid var(--line);
}

.section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: 24px;
}

.search-wrap {
  width: min(420px, 100%);
}

.sound-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(292px, 1fr));
  gap: 16px;
}

.sound-card {
  display: flex;
  flex-direction: column;
  gap: 16px;
  min-height: 230px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  padding: 18px;
  box-shadow: 0 10px 28px rgba(29, 42, 38, 0.08);
}

.card-topline {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.rank,
.frequency {
  display: inline-flex;
  align-items: center;
  min-height: 28px;
  border-radius: 999px;
  padding: 0 10px;
  font-size: 0.86rem;
  font-weight: 800;
}

.rank {
  background: var(--sky);
  color: #234c59;
}

.frequency {
  background: #fff5dd;
  color: #7d4c08;
}

.sound-main {
  display: grid;
  grid-template-columns: 48px minmax(0, 1fr);
  gap: 12px;
  align-items: center;
}

.sound-main h3 {
  font-size: 2rem;
  line-height: 1;
}

.sound-main p {
  margin: 7px 0 0;
  color: var(--muted);
}

.bar {
  height: 8px;
  border-radius: 999px;
  background: #e8ece9;
  overflow: hidden;
}

.bar span {
  display: block;
  width: var(--bar);
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--green), var(--gold));
}

.letter-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.letter-chip {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  min-height: 42px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fbfdfc;
  color: var(--charcoal);
  padding: 0 10px;
  cursor: pointer;
}

.letter-chip:hover,
.letter-chip:focus-visible,
.letter-tile:hover,
.letter-tile:focus-visible {
  border-color: var(--green);
  background: var(--green-soft);
  outline: none;
}

.thai {
  color: var(--green);
  font-family: "Noto Sans Thai", Tahoma, sans-serif;
  font-size: 1.55rem;
  font-weight: 800;
  line-height: 1;
}

.letter-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(132px, 1fr));
  gap: 12px;
}

.letter-tile {
  display: grid;
  gap: 4px;
  min-height: 126px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
  padding: 14px 12px;
  text-align: left;
  cursor: pointer;
}

.tile-char {
  color: var(--green);
  font-family: "Noto Sans Thai", Tahoma, sans-serif;
  font-size: 2.8rem;
  font-weight: 800;
  line-height: 1;
}

.tile-name {
  font-family: "Noto Sans Thai", Tahoma, sans-serif;
  font-size: 1.05rem;
  font-weight: 800;
}

.tile-meta {
  color: var(--muted);
  font-size: 0.86rem;
}

.practice-layout {
  display: grid;
  grid-template-columns: minmax(260px, 0.68fr) minmax(300px, 1.32fr);
  gap: 18px;
  align-items: stretch;
}

.quiz-panel,
.answer-panel {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  padding: 18px;
  box-shadow: 0 10px 28px rgba(29, 42, 38, 0.08);
}

.quiz-panel {
  display: grid;
  align-content: center;
  justify-items: center;
  min-height: 280px;
  text-align: center;
}

.quiz-thai {
  color: var(--green);
  font-family: "Noto Sans Thai", Tahoma, sans-serif;
  font-size: 7rem;
  font-weight: 800;
  line-height: 1;
}

.quiz-name {
  min-height: 32px;
  margin: 8px 0 18px;
  color: var(--muted);
}

.large {
  width: 54px;
  height: 54px;
  font-size: 1.1rem;
}

.answers {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.answers button {
  display: grid;
  gap: 4px;
  min-height: 70px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
  padding: 10px 12px;
  text-align: left;
  cursor: pointer;
}

.answers button:hover,
.answers button:focus-visible {
  border-color: var(--green);
  background: var(--green-soft);
  outline: none;
}

.answers strong {
  font-size: 1.18rem;
}

.answers span {
  color: var(--muted);
  font-size: 0.88rem;
}

.answers .is-correct {
  border-color: #1f8a5c;
  background: #e0f4e8;
}

.answers .is-wrong {
  border-color: #c14437;
  background: #ffe8e5;
}

.feedback {
  min-height: 28px;
  margin-top: 14px;
  color: var(--charcoal);
  font-weight: 800;
}

.empty-state {
  border: 1px dashed var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--muted);
  padding: 24px;
}

.footer {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  padding: 24px 44px 34px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.92rem;
}

@media (max-width: 1080px) {
  .topbar,
  .hero,
  .section,
  .footer {
    padding-inline: 28px;
  }

  .control-strip {
    grid-template-columns: repeat(3, minmax(140px, 1fr));
    margin-inline: 28px;
  }

  .hero {
    grid-template-columns: 1fr;
  }

  .hero-media {
    max-width: 760px;
  }
}

@media (max-width: 760px) {
  .topbar {
    align-items: flex-start;
    flex-direction: column;
    gap: 10px;
    padding: 12px 18px;
  }

  .nav {
    width: 100%;
    overflow-x: auto;
    padding-bottom: 2px;
  }

  .nav a {
    padding-inline: 10px;
  }

  .hero,
  .section,
  .footer {
    padding-inline: 18px;
  }

  .hero {
    gap: 26px;
    padding-top: 36px;
  }

  h1 {
    font-size: 3.15rem;
  }

  h2 {
    font-size: 1.9rem;
  }

  .hero-subtitle {
    font-size: 1rem;
  }

  .control-strip {
    grid-template-columns: 1fr 1fr;
    margin: 0 18px 18px;
  }

  .offline-action {
    grid-column: 1 / -1;
  }

  .section-heading {
    align-items: stretch;
    flex-direction: column;
    gap: 14px;
  }

  .sound-grid {
    grid-template-columns: 1fr;
  }

  .letter-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .practice-layout {
    grid-template-columns: 1fr;
  }

  .answers {
    grid-template-columns: 1fr;
  }

  .footer {
    flex-direction: column;
  }
}

@media (max-width: 420px) {
  .control-strip {
    grid-template-columns: 1fr;
  }

  .icon-button {
    width: 100%;
  }

  .letter-grid {
    grid-template-columns: 1fr;
  }

  .quiz-thai {
    font-size: 5.2rem;
  }
}