@import url("https://fonts.googleapis.com/css2?family=IBM+Plex+Sans:wght@400;500;600&family=IBM+Plex+Serif:wght@500;600&display=swap");

:root {
  --bg: #f6f7f9;
  --ink: #1b1f24;
  --muted: #5b6470;
  --card: #ffffff;
  --border: #e2e6ec;
  --accent: #2f3a4a;
  --accent-dark: #1f2733;
  --shadow: rgba(15, 20, 30, 0.08);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "IBM Plex Sans", "Segoe UI", sans-serif;
  color: var(--ink);
  background: var(--bg);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 32px 20px;
}

.app {
  width: min(720px, 100%);
  display: grid;
  gap: 28px;
  animation: fadeIn 0.8s ease-out;
}

.app-header {
  text-align: center;
  display: grid;
  gap: 12px;
}

h1 {
  margin: 0;
  font-family: "IBM Plex Serif", serif;
  font-size: clamp(2.4rem, 5vw, 3.4rem);
}

.card {
  background: var(--card);
  border-radius: 18px;
  border: 1px solid var(--border);
  padding: clamp(24px, 4vw, 36px);
  box-shadow: 0 12px 30px var(--shadow);
  display: grid;
  gap: 24px;
  text-align: center;
}

.vocab-section {
  background: var(--card);
  border-radius: 16px;
  border: 1px solid var(--border);
  padding: clamp(18px, 3vw, 28px);
  box-shadow: 0 10px 24px var(--shadow);
  display: grid;
  gap: 16px;
}

.vocab-title {
  margin: 0;
  font-family: "IBM Plex Serif", serif;
  font-size: 1.3rem;
}

.vocab-list {
  margin: 0;
  padding-left: 1.5rem;
  display: grid;
  gap: 6px;
  color: var(--ink);
}

.is-hidden {
  display: none;
}

.status {
  font-size: 1.15rem;
  color: var(--muted);
}

.word {
  font-family: "IBM Plex Serif", serif;
  font-size: clamp(3rem, 14vw, 7rem);
  line-height: 1.05;
  min-height: 6rem;
  display: flex;
  align-items: center;
  justify-content: center;
  letter-spacing: 0.02em;
  transition: opacity 0.2s ease, transform 0.2s ease;
}

.word.hidden {
  opacity: 0.2;
  transform: scale(0.98);
}

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  justify-content: center;
}

.voice-picker {
  display: grid;
  gap: 8px;
  text-align: left;
}

.download {
  margin: 0;
  text-align: center;
}

.voice-picker label {
  font-size: 0.85rem;
  color: var(--muted);
}

.select {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px 12px;
  font-size: 0.95rem;
  background: #fff;
  color: var(--ink);
}

.help {
  margin: 0;
  font-size: 0.9rem;
  color: var(--muted);
}

.btn {
  border: 1px solid var(--border);
  padding: 14px 20px;
  border-radius: 12px;
  background: transparent;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 8px 18px var(--shadow);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  box-shadow: none;
  transform: none;
}

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--accent-dark);
  border-color: var(--accent-dark);
}

.btn-reveal {
  align-self: center;
}

.controls-break {
  flex-basis: 100%;
  height: 0;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}