:root {
  color-scheme: dark;
  --bg: #10131a;
  --panel: #181d27;
  --text: #f3f6fb;
  --muted: #aab4c3;
  --accent: #19c37d;
  --accent-strong: #5be8ad;
  --danger: #ff6b6b;
}

* {
  box-sizing: border-box;
}

html,
body {
  width: 100%;
  min-height: 100%;
  margin: 0;
}

body {
  font-family: Arial, Helvetica, sans-serif;
  background:
    radial-gradient(circle at 20% 15%, rgba(25, 195, 125, 0.18), transparent 28rem),
    linear-gradient(135deg, #10131a 0%, #1c2430 48%, #111820 100%);
  color: var(--text);
}

.registration-gate {
  position: fixed;
  inset: 0;
  z-index: 10;
  display: grid;
  place-items: center;
  padding: 1.25rem;
  background: rgba(16, 19, 26, 0.96);
}

.registration-gate[hidden] {
  display: none;
}

.registration-card {
  width: min(30rem, 100%);
  display: grid;
  gap: 0.85rem;
  padding: clamp(1.5rem, 5vw, 2.25rem);
  border: 1px solid rgba(255, 255, 255, 0.16);
  border-radius: 8px;
  background: rgba(24, 29, 39, 0.96);
  box-shadow: 0 1.5rem 5rem rgba(0, 0, 0, 0.42);
}

.registration-kicker {
  margin: 0;
  color: var(--accent-strong);
  font-size: 0.9rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.12em;
}

.registration-card h1 {
  margin: 0;
  color: var(--text);
  font-size: clamp(2rem, 7vw, 3.25rem);
  line-height: 1;
}

.registration-copy,
.registration-notice,
.registration-message {
  margin: 0;
  color: var(--muted);
  line-height: 1.45;
}

.registration-notice {
  padding: 0.75rem;
  border-left: 3px solid var(--accent);
  background: rgba(25, 195, 125, 0.08);
}

.registration-card label {
  color: var(--text);
  font-weight: 700;
}

.registration-card input {
  width: 100%;
  height: 2.8rem;
  padding: 0 0.8rem;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 8px;
  background: rgba(16, 19, 26, 0.9);
  color: var(--text);
  font: inherit;
}

.registration-card input:focus-visible {
  border-color: var(--accent);
  outline: none;
}

.registration-submit {
  height: 2.9rem;
  margin-top: 0.25rem;
  border: 1px solid var(--accent);
  border-radius: 8px;
  background: var(--accent);
  color: #07120d;
  font-size: 1rem;
  font-weight: 800;
  cursor: pointer;
}

.registration-submit:disabled {
  cursor: progress;
  opacity: 0.75;
}

.registration-message {
  min-height: 1.4rem;
}

.trainer {
  height: 100vh;
  display: grid;
  grid-template-columns: minmax(13rem, 15.5rem) minmax(0, 1fr);
  gap: clamp(0.75rem, 2vw, 1.35rem);
  align-items: stretch;
  overflow: hidden;
  padding: clamp(0.75rem, 2vw, 1.25rem);
}

.control-panel {
  min-width: 0;
  min-height: 0;
  max-height: calc(100vh - clamp(0.75rem, 2vw, 1.25rem) * 2);
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
  overflow-y: auto;
  padding: 0.75rem;
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 8px;
  background: rgba(16, 19, 26, 0.82);
  box-shadow: 0 1.5rem 5rem rgba(0, 0, 0, 0.28);
}

.app-header {
  display: grid;
  gap: 0.15rem;
  padding-bottom: 0.55rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
}

.app-header h1 {
  margin: 0;
  color: var(--text);
  font-size: 0.98rem;
  line-height: 1.14;
}

.version-label {
  margin: 0;
  color: var(--muted);
  font-size: 0.75rem;
}

.contact-link {
  color: var(--accent-strong);
  overflow-wrap: anywhere;
  text-decoration: none;
}

.contact-link:hover,
.contact-link:focus-visible {
  color: var(--text);
  outline: none;
  text-decoration: underline;
}

.menu {
  display: grid;
  gap: 0.4rem;
}

.exit-button,
.menu-button,
.secondary-button {
  height: 2.4rem;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 8px;
  background: rgba(24, 29, 39, 0.9);
  color: var(--text);
  font-size: 0.95rem;
  font-weight: 700;
  cursor: pointer;
}

.exit-button {
  width: 100%;
}

.panel-footer {
  margin: auto 0 0;
  display: grid;
  gap: 0.25rem;
}

.contact-note,
.copyright-note {
  margin: 0;
  color: var(--muted);
  font-size: 0.72rem;
  line-height: 1.3;
}

.menu-button {
  width: 100%;
  padding: 0 0.8rem;
}

.secondary-button {
  width: 100%;
  padding: 0 0.8rem;
}

.exit-button:hover,
.exit-button:focus-visible,
.menu-button:hover,
.menu-button:focus-visible,
.secondary-button:hover,
.secondary-button:focus-visible {
  border-color: var(--danger);
  color: #fff;
  outline: none;
}

.menu-button.active,
.secondary-button:hover,
.secondary-button:focus-visible {
  border-color: var(--accent);
}

.display {
  min-width: 0;
  align-self: center;
  max-height: calc(100vh - clamp(0.75rem, 2vw, 1.25rem) * 2);
  width: min(52rem, 100%);
  display: grid;
  justify-items: center;
  gap: 0.65rem;
  overflow: hidden;
  padding: clamp(1rem, 3vw, 2.25rem);
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 8px;
  background: rgba(16, 19, 26, 0.76);
  box-shadow: 0 1.5rem 5rem rgba(0, 0, 0, 0.34);
}

.settings-panel {
  width: 100%;
  color: var(--muted);
}

.settings-toggle {
  width: 100%;
  min-height: 2.25rem;
  padding: 0.3rem 0.65rem;
  border: 1px solid rgba(255, 255, 255, 0.16);
  border-radius: 8px;
  background: transparent;
  color: var(--text);
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}

.settings-toggle:hover,
.settings-toggle:focus-visible {
  border-color: var(--accent);
  outline: none;
}

.settings-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.48rem;
  margin-top: 0.5rem;
  padding: 0.6rem;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 8px;
  background: rgba(24, 29, 39, 0.72);
}

.settings-grid[hidden] {
  display: none;
}

.settings-grid label {
  display: grid;
  gap: 0.15rem;
  font-size: 0.88rem;
  font-weight: 700;
}

.settings-grid label span {
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 400;
}

.settings-grid input,
.settings-grid select {
  width: 100%;
  accent-color: var(--accent);
}

.settings-grid select {
  min-height: 2.15rem;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 8px;
  background: rgba(16, 19, 26, 0.9);
  color: var(--text);
  font: inherit;
}

.voice-preview-button {
  height: 2.25rem;
}

.reset-progress-button {
  border-color: rgba(255, 107, 107, 0.42);
}

.settings-message {
  min-height: 1rem;
  margin: 0;
  color: var(--accent-strong);
  font-size: 0.78rem;
  line-height: 1.25;
}

.prompt {
  max-width: min(46rem, 100%);
  margin: 0;
  color: var(--muted);
  font-size: clamp(0.95rem, 1.6vw, 1.25rem);
  line-height: 1.35;
  overflow-wrap: anywhere;
  text-align: center;
  text-transform: uppercase;
  letter-spacing: 0.12em;
}

.letter-display {
  width: 100%;
  max-width: 100%;
  line-height: 0.9;
  min-height: clamp(7.5rem, 25vw, 15rem);
  display: grid;
  place-items: center;
  color: var(--text);
  font-size: clamp(7.5rem, 28vw, 17rem);
  font-weight: 900;
  overflow-wrap: anywhere;
  text-align: center;
}

.morse-display {
  min-height: 3rem;
  color: var(--accent-strong);
  font-family: "Courier New", Courier, monospace;
  font-size: clamp(2.1rem, 6vw, 4.25rem);
  font-weight: 700;
}

.quiz-controls {
  display: grid;
  gap: 0.4rem;
  min-height: 2.4rem;
}

.keyboard-hints {
  display: grid;
  gap: 0.25rem;
  color: var(--muted);
  text-align: center;
}

.replay-hint,
.exit-mode-hint {
  margin: 0;
  color: var(--muted);
  font-size: 0.84rem;
  line-height: 1.35;
}

.replay-hint kbd,
.exit-mode-hint kbd {
  display: inline-block;
  min-width: 2.6rem;
  padding: 0.15rem 0.45rem;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 6px;
  background: rgba(24, 29, 39, 0.9);
  color: var(--text);
  font: inherit;
  font-size: 0.85rem;
  font-weight: 800;
  text-align: center;
}

.word-practice {
  width: min(30rem, 100%);
  display: grid;
  gap: 0.5rem;
  justify-items: center;
}

.word-practice input {
  width: min(18rem, 100%);
  height: 2.7rem;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 8px;
  background: rgba(16, 19, 26, 0.9);
  color: var(--text);
  font: inherit;
  font-size: 1.25rem;
  font-weight: 700;
  text-align: center;
  text-transform: uppercase;
}

.word-practice input:focus-visible {
  border-color: var(--accent);
  outline: none;
}

.word-actions {
  display: grid;
  gap: 0.4rem;
}

.word-session-setting,
.session-setting {
  display: grid;
  gap: 0.25rem;
  color: var(--muted);
  font-size: 0.86rem;
  font-weight: 700;
}

.word-session-setting select,
.session-setting select {
  width: 100%;
  min-height: 2.25rem;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 8px;
  background: rgba(16, 19, 26, 0.92);
  color: var(--text);
  font: inherit;
  font-weight: 700;
}

.word-session-status {
  min-height: 1.1rem;
  margin: 0;
  color: var(--accent-strong);
  font-size: 0.82rem;
  font-weight: 700;
  line-height: 1.25;
  text-align: center;
}

.word-feedback {
  min-height: 1.3rem;
  margin: 0;
  color: var(--muted);
  font-size: clamp(0.92rem, 1.5vw, 1.05rem);
  text-align: center;
}

.leaderboard-note {
  max-width: 30rem;
  margin: 0;
  color: var(--muted);
  font-size: 0.82rem;
  line-height: 1.35;
  text-align: center;
}

.leaderboard-opt-in {
  width: min(30rem, 100%);
  display: grid;
  gap: 0.55rem;
  padding: 0.7rem;
  border: 1px solid rgba(25, 195, 125, 0.28);
  border-radius: 8px;
  background: rgba(25, 195, 125, 0.08);
}

.leaderboard-opt-in[hidden] {
  display: none;
}

.leaderboard-opt-in p {
  margin: 0;
  color: var(--text);
  font-size: 0.9rem;
  line-height: 1.35;
  text-align: center;
}

.leaderboard-opt-in-actions {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.5rem;
}

.leaderboard-view {
  width: min(38rem, 100%);
  display: grid;
  gap: 0.8rem;
}

.leaderboard-view[hidden] {
  display: none;
}

.leaderboard-header {
  display: flex;
  flex-wrap: wrap;
  align-items: end;
  justify-content: space-between;
  gap: 0.75rem;
}

.leaderboard-header h2 {
  margin: 0;
  color: var(--text);
  font-size: clamp(1.35rem, 4vw, 2rem);
}

.leaderboard-header label {
  display: grid;
  gap: 0.25rem;
  color: var(--muted);
  font-size: 0.86rem;
  font-weight: 700;
}

.leaderboard-header select {
  min-height: 2.35rem;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 8px;
  background: rgba(16, 19, 26, 0.92);
  color: var(--text);
  font: inherit;
  font-weight: 700;
}

.leaderboard-list {
  display: grid;
  gap: 0.45rem;
  margin: 0;
  padding-left: 1.5rem;
}

.leaderboard-list li {
  padding: 0.55rem 0.65rem;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 8px;
  background: rgba(24, 29, 39, 0.72);
}

.leaderboard-person,
.leaderboard-result {
  display: block;
}

.leaderboard-result {
  color: var(--accent-strong);
  font-weight: 800;
}

.leaderboard-message {
  min-height: 1.2rem;
  margin: 0;
  color: var(--muted);
  text-align: center;
}

.scoreboard {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: clamp(0.75rem, 4vw, 2rem);
  width: min(34rem, 100%);
  min-height: 2.35rem;
  padding: 0.55rem 0.8rem;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  color: var(--muted);
  font-size: clamp(0.92rem, 1.5vw, 1.05rem);
}

.scoreboard strong {
  color: var(--text);
}

.is-practice .quiz-controls,
.is-practice .scoreboard,
.is-practice .learn-status,
.is-practice .leaderboard-note,
.is-quiz #levelStat,
.is-word #levelStat,
.is-word .learn-status,
.is-word .session-setting,
.is-word #scoredSessionStatus,
.is-practice .word-actions,
.is-quiz .word-actions,
.is-learn .word-actions,
.is-leaderboard .word-actions,
.is-leaderboard .quiz-controls,
.is-leaderboard .leaderboard-note,
.is-leaderboard .word-practice,
.is-leaderboard .letter-display,
.is-leaderboard .morse-display,
.is-leaderboard .keyboard-hints,
.is-leaderboard .scoreboard,
.is-leaderboard .learn-status,
body:not(.is-word) .word-practice {
  display: none;
}

.is-quiz .morse-display,
.is-learn .morse-display,
.is-word .morse-display {
  color: var(--muted);
  font-size: clamp(1.35rem, 3vw, 2rem);
}

.is-word .letter-display {
  min-height: clamp(4.75rem, 16vw, 9rem);
  font-size: clamp(4.75rem, 16vw, 9rem);
}

.learn-status {
  max-width: 38rem;
  margin: 0;
  color: var(--muted);
  font-size: clamp(0.9rem, 1.5vw, 1.05rem);
  text-align: center;
}

.flash {
  animation: flash 180ms ease-out;
}

@keyframes flash {
  from {
    color: var(--accent);
    transform: scale(1.04);
  }
  to {
    color: var(--text);
    transform: scale(1);
  }
}

@media (max-width: 720px) {
  .trainer {
    height: auto;
    min-height: 100vh;
    grid-template-columns: 1fr;
    align-items: start;
    overflow: visible;
    width: 100%;
  }

  .control-panel {
    width: 100%;
    min-height: auto;
    max-height: none;
    overflow: visible;
  }

  .display {
    width: 100%;
    align-self: stretch;
    max-height: none;
    overflow: visible;
  }

  .letter-display {
    min-height: clamp(5rem, 28vw, 7.5rem);
    max-width: 100%;
    font-size: clamp(4.75rem, 25vw, 7.5rem);
    overflow-wrap: anywhere;
  }

  .morse-display {
    max-width: 100%;
    font-size: clamp(1.8rem, 12vw, 3rem);
    overflow-wrap: anywhere;
  }
}