:root {
  --bg: #0e1411;
  --bg-2: #151c18;
  --card: #1c2520;
  --card-2: #232e27;
  --border: #2c3a32;
  --text: #e8efe9;
  --muted: #8a9b91;
  --accent: #19c37d;
  --accent-dim: #149464;
  --accent-soft: rgba(25, 195, 125, 0.12);
  --warn: #f5a524;
  --bad: #ef4444;
  --bad-soft: rgba(239, 68, 68, 0.12);
  --ok: #19c37d;
  --shadow: 0 6px 24px rgba(0,0,0,0.35);
  --radius: 14px;
}

* { box-sizing: border-box; }
html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Inter", Roboto, sans-serif;
  font-size: 16px;
  min-height: 100vh;
}
button {
  font-family: inherit;
  cursor: pointer;
}

/* topbar */
#topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 22px;
  background: var(--bg-2);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 5;
}
.brand {
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 0.3px;
  cursor: pointer;
}
.topbar-stats { display: flex; gap: 8px; }
.pill {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 6px 12px;
  font-size: 13px;
  font-weight: 600;
}
.pill.due { color: var(--warn); }

/* layout */
#app {
  max-width: 880px;
  margin: 0 auto;
  padding: 28px 22px 60px;
}
.view.hidden { display: none; }
.hidden { display: none !important; }
.hero h1 { font-size: 32px; margin: 0 0 6px; }
.muted { color: var(--muted); }
.section-title {
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 1.2px;
  color: var(--muted);
  margin: 32px 0 14px;
}
.cta-row { display: flex; gap: 10px; margin-top: 18px; flex-wrap: wrap; }

/* buttons */
.btn {
  border: none;
  border-radius: var(--radius);
  padding: 10px 18px;
  font-size: 15px;
  font-weight: 600;
  background: var(--card);
  color: var(--text);
  border: 1px solid var(--border);
  transition: transform 0.05s ease, background 0.15s ease, border-color 0.15s ease;
}
.btn:hover:not(:disabled) { background: var(--card-2); }
.btn:active:not(:disabled) { transform: translateY(1px); }
.btn.primary {
  background: var(--accent);
  color: #06281a;
  border-color: var(--accent);
}
.btn.primary:hover:not(:disabled) { background: var(--accent-dim); border-color: var(--accent-dim); }
.btn.primary:disabled, .btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}
.btn.ghost {
  background: transparent;
}
.btn.big {
  padding: 14px 22px;
  font-size: 16px;
}
.btn-icon {
  background: transparent;
  border: none;
  color: var(--muted);
  font-size: 22px;
  width: 36px;
  height: 36px;
  border-radius: 8px;
}
.btn-icon:hover { background: var(--card); color: var(--text); }

/* lesson grid */
.lesson-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 14px;
}
.lesson-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
  cursor: pointer;
  transition: transform 0.1s ease, border-color 0.15s ease;
  display: flex;
  flex-direction: column;
  gap: 8px;
  position: relative;
  overflow: hidden;
}
.lesson-card:hover { border-color: var(--accent); transform: translateY(-2px); }
.lesson-emoji { font-size: 28px; }
.lesson-title { font-size: 17px; font-weight: 600; }
.lesson-meta { color: var(--muted); font-size: 13px; }
.lesson-progress {
  height: 6px;
  background: var(--bg);
  border-radius: 3px;
  overflow: hidden;
  margin-top: 6px;
}
.lesson-progress > div {
  height: 100%;
  background: var(--accent);
  transition: width 0.3s ease;
}
.lesson-card.done::after {
  content: '✓';
  position: absolute;
  top: 12px; right: 14px;
  color: var(--accent);
  font-weight: 700;
}

/* session */
.session-header {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 32px;
}
.progress-wrap { flex: 1; }
.progress-bar {
  height: 8px;
  background: var(--card);
  border-radius: 4px;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  background: var(--accent);
  width: 0%;
  transition: width 0.25s ease;
}
.session-stats { font-weight: 600; font-size: 14px; }
.session-stats .ok { color: var(--accent); }

.session-body {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 36px 28px;
  min-height: 360px;
  display: flex;
  flex-direction: column;
  gap: 22px;
}

.prompt-label {
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 1.4px;
  color: var(--muted);
}
.prompt-word {
  font-size: 38px;
  font-weight: 700;
  text-align: center;
  padding: 14px 0;
}
.prompt-word.small { font-size: 26px; }
.audio-btn {
  background: var(--card-2);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 999px;
  width: 56px;
  height: 56px;
  font-size: 22px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto;
  cursor: pointer;
}
.audio-btn:hover { background: var(--accent-soft); border-color: var(--accent); }
.audio-btn.large { width: 88px; height: 88px; font-size: 36px; }

/* multiple choice */
.choices { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.choice {
  background: var(--card-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  text-align: left;
  font-size: 16px;
  color: var(--text);
  transition: background 0.1s ease, border-color 0.1s ease;
}
.choice .num {
  display: inline-block;
  width: 22px;
  height: 22px;
  text-align: center;
  font-size: 12px;
  border-radius: 4px;
  background: var(--bg);
  color: var(--muted);
  margin-right: 10px;
  line-height: 22px;
}
.choice:hover:not(:disabled) { border-color: var(--accent); }
.choice.right { background: var(--accent-soft); border-color: var(--accent); color: var(--text); }
.choice.wrong { background: var(--bad-soft); border-color: var(--bad); }
.choice:disabled { cursor: default; }

/* typing */
.typing-input {
  width: 100%;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 16px;
  font-size: 22px;
  color: var(--text);
  text-align: center;
  outline: none;
  font-family: inherit;
}
.typing-input:focus { border-color: var(--accent); }
.typing-input.right { border-color: var(--accent); background: var(--accent-soft); }
.typing-input.wrong { border-color: var(--bad); background: var(--bad-soft); }
.accent-row {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  justify-content: center;
}
.accent-key {
  background: var(--card-2);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 8px;
  padding: 6px 12px;
  font-size: 16px;
  cursor: pointer;
}
.accent-key:hover { border-color: var(--accent); }

/* feedback footer */
.session-footer {
  margin-top: 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  padding: 14px 18px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.session-footer.right { border-color: var(--accent); }
.session-footer.wrong { border-color: var(--bad); }
.feedback { font-size: 14px; }
.feedback strong { color: var(--accent); }
.feedback.wrong strong { color: var(--bad); }

/* learn presentation card */
.learn-card {
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 14px;
  align-items: center;
}
.learn-card .es { font-size: 44px; font-weight: 700; }
.learn-card .en { font-size: 22px; color: var(--muted); }
.learn-card .badge {
  background: var(--accent-soft);
  color: var(--accent);
  border-radius: 999px;
  padding: 4px 12px;
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1.2px;
}

/* speed timer */
.speed-timer {
  height: 4px;
  background: var(--accent);
  border-radius: 2px;
  width: 100%;
  transition: width 0.1s linear;
}

/* done */
.done-card {
  text-align: center;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 48px 28px;
  margin: 40px auto;
  max-width: 480px;
}
.done-emoji { font-size: 64px; margin-bottom: 8px; }
.done-stats {
  display: flex;
  justify-content: center;
  gap: 28px;
  margin: 24px 0 28px;
}
.done-stats .stat { display: flex; flex-direction: column; gap: 4px; }
.done-stats .num { font-size: 28px; font-weight: 700; color: var(--accent); }
.done-stats .lbl { font-size: 12px; text-transform: uppercase; letter-spacing: 1px; color: var(--muted); }

/* video embeds */
.video-frame {
  position: relative;
  width: 100%;
  max-width: 480px;
  margin: 4px auto 0;
  aspect-ratio: 16 / 9;
  background: #000;
  border-radius: 12px;
  overflow: hidden;
  border: 1px solid var(--border);
}
.video-frame iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}
.no-video-hint {
  font-size: 13px;
  color: var(--muted);
  text-align: center;
  padding: 6px 0;
}

/* nav-pill (button) */
.pill.nav-pill {
  cursor: pointer;
  color: var(--text);
  transition: border-color 0.12s ease, background 0.12s ease;
}
.pill.nav-pill:hover { border-color: var(--accent); background: var(--card-2); }

/* library */
.lib-search {
  background: var(--card);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 10px 14px;
  border-radius: var(--radius);
  font-size: 14px;
  flex: 1;
  max-width: 360px;
  font-family: inherit;
  outline: none;
}
.lib-search:focus { border-color: var(--accent); }
.library-list { display: flex; flex-direction: column; gap: 8px; }
.library-group {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 18px;
}
.library-group h3 {
  margin: 0 0 10px;
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 1.2px;
  color: var(--muted);
  display: flex;
  align-items: center;
  gap: 8px;
}
.lib-row {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 0;
  border-top: 1px solid var(--border);
}
.lib-row:first-of-type { border-top: none; }
.lib-row .es { font-weight: 600; min-width: 140px; }
.lib-row .en { color: var(--muted); flex: 1; }
.lib-row .vid-status {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 1px;
  font-weight: 600;
  padding: 4px 8px;
  border-radius: 999px;
}
.lib-row .vid-status.has { background: var(--accent-soft); color: var(--accent); }
.lib-row .vid-status.no { background: var(--bg); color: var(--muted); }
.lib-row button {
  font-size: 13px;
  padding: 6px 12px;
}

/* modal */
.modal {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.7);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 50;
  padding: 20px;
}
.modal-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  width: 100%;
  max-width: 540px;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: var(--shadow);
}
.modal-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 6px;
}
.modal-card h2 { margin: 0; font-size: 20px; }
.modal-card .lbl {
  display: block;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--muted);
  margin: 14px 0 6px;
}
.modal-card input[type="text"], .modal-card input[type="number"] {
  width: 100%;
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 10px;
  padding: 10px 12px;
  font-size: 14px;
  font-family: inherit;
  outline: none;
}
.modal-card input:focus { border-color: var(--accent); }
.modal-row { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.modal-preview { margin-top: 16px; }
.modal-preview .video-frame { margin-top: 0; }
.modal-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 20px;
}
.btn.danger-link {
  background: transparent;
  border: none;
  color: var(--bad);
  padding: 8px 4px;
  font-weight: 500;
}
.btn.danger-link:hover { color: var(--text); }

@media (max-width: 540px) {
  .choices { grid-template-columns: 1fr; }
  .prompt-word { font-size: 30px; }
  .learn-card .es { font-size: 36px; }
  #app { padding: 18px 14px 40px; }
  .session-body { padding: 24px 18px; }
}