:root {
  --bg-deep: #0c2e2a;
  --bg-mid: #134038;
  --bg-lift: #1a5248;
  --ink: #f3efe6;
  --ink-muted: #b8c4b8;
  --accent: #e9c46a;
  --accent-hot: #f4a261;
  --good: #2a9d8f;
  --again: #e76f51;
  --hard: #e9c46a;
  --easy: #8ecae6;
  --surface: rgba(243, 239, 230, 0.08);
  --surface-strong: rgba(243, 239, 230, 0.14);
  --line: rgba(243, 239, 230, 0.16);
  --shadow: 0 24px 60px rgba(0, 0, 0, 0.35);
  --radius: 18px;
  --font-display: 'Fraunces', Georgia, serif;
  --font-body: 'Sora', system-ui, sans-serif;
  color: var(--ink);
  background: var(--bg-deep);
  font-family: var(--font-body);
  font-synthesis: none;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

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

body {
  min-height: 100dvh;
}

button,
input,
textarea {
  font: inherit;
  color: inherit;
}

button {
  cursor: pointer;
}

.app-shell {
  position: relative;
  min-height: 100dvh;
  overflow-x: hidden;
}

.atmosphere {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background:
    radial-gradient(ellipse 80% 50% at 10% -10%, rgba(233, 196, 106, 0.22), transparent 55%),
    radial-gradient(ellipse 60% 45% at 100% 0%, rgba(42, 157, 143, 0.35), transparent 50%),
    radial-gradient(ellipse 50% 40% at 50% 100%, rgba(244, 162, 97, 0.12), transparent 55%),
    linear-gradient(165deg, var(--bg-deep), var(--bg-mid) 45%, #0a2420);
  animation: atmosphere-drift 18s ease-in-out infinite alternate;
}

@keyframes atmosphere-drift {
  from {
    filter: hue-rotate(0deg) saturate(1);
    transform: scale(1);
  }
  to {
    filter: hue-rotate(8deg) saturate(1.08);
    transform: scale(1.03);
  }
}

.page {
  position: relative;
  z-index: 1;
  width: min(720px, 100%);
  margin: 0 auto;
  padding: 1.25rem 1.25rem 3rem;
}

.boot {
  min-height: 100dvh;
  display: grid;
  place-content: center;
  gap: 0.75rem;
  text-align: center;
  background: linear-gradient(165deg, var(--bg-deep), var(--bg-mid));
}

.brand-mark {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(2.6rem, 8vw, 4rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 0.95;
  color: var(--ink);
  animation: brand-in 0.7s ease both;
}

.boot-hint,
.home-sub,
.page-sub,
.empty-hint,
.stats-line {
  color: var(--ink-muted);
}

.boot-hint {
  margin: 0;
}

@keyframes brand-in {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.home-hero {
  padding: 2.5rem 0 1.5rem;
  animation: rise 0.65s ease both;
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(18px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.home-title,
.page-title {
  margin: 0.35rem 0 0.75rem;
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 5vw, 2.4rem);
  font-weight: 500;
  line-height: 1.15;
  letter-spacing: -0.02em;
}

.home-sub {
  margin: 0 0 1.5rem;
  max-width: 28rem;
  line-height: 1.55;
}

.home-actions,
.form-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.btn {
  border: 1px solid transparent;
  border-radius: 999px;
  padding: 0.7rem 1.2rem;
  background: var(--surface);
  transition: transform 0.15s ease, background 0.15s ease, border-color 0.15s ease;
}

.btn:hover:not(:disabled) {
  transform: translateY(-1px);
}

.btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--accent);
  color: #1a1a12;
  font-weight: 600;
}

.btn-primary:hover:not(:disabled) {
  background: #f0d27e;
}

.btn-secondary {
  border-color: var(--line);
  background: var(--surface-strong);
}

.btn-ghost {
  background: transparent;
  border-color: transparent;
  color: var(--ink-muted);
}

.btn-study {
  background: var(--good);
  color: #04201c;
  font-weight: 600;
  padding-inline: 1rem;
}

.btn-icon {
  width: 2.4rem;
  height: 2.4rem;
  padding: 0;
  border-radius: 50%;
  font-size: 1.35rem;
  line-height: 1;
  color: var(--ink-muted);
}

.create-form,
.editor-form {
  display: grid;
  gap: 0.65rem;
  margin-bottom: 1.5rem;
  padding: 1.1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  animation: rise 0.4s ease both;
}

.create-form label,
.editor-form label {
  font-size: 0.85rem;
  color: var(--ink-muted);
}

.create-form input,
.editor-form textarea {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 0.85rem 1rem;
  background: rgba(0, 0, 0, 0.22);
  resize: vertical;
}

.create-form input:focus,
.editor-form textarea:focus {
  outline: 2px solid rgba(233, 196, 106, 0.45);
  outline-offset: 1px;
}

.deck-list {
  display: grid;
  gap: 0.75rem;
  animation: rise 0.7s ease both;
  animation-delay: 0.08s;
}

.deck-row,
.card-item {
  display: flex;
  align-items: stretch;
  gap: 0.5rem;
}

.deck-main,
.card-item-main {
  flex: 1;
  display: flex;
  align-items: center;
  gap: 0.9rem;
  text-align: left;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1rem 1.05rem;
  background: var(--surface);
  transition: background 0.15s ease, border-color 0.15s ease;
}

.deck-main:hover,
.card-item-main:hover {
  background: var(--surface-strong);
  border-color: rgba(233, 196, 106, 0.35);
}

.deck-accent {
  width: 0.35rem;
  align-self: stretch;
  border-radius: 999px;
  background: var(--deck-accent, var(--good));
}

.deck-body {
  display: grid;
  gap: 0.2rem;
}

.deck-name {
  font-weight: 600;
  font-size: 1.05rem;
}

.deck-meta {
  font-size: 0.85rem;
  color: var(--ink-muted);
}

.deck-side {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.page-header {
  margin-bottom: 1.5rem;
}

.page-header .back {
  margin-left: -0.4rem;
  margin-bottom: 0.5rem;
}

.stats-line {
  margin: 0 0 1.25rem;
  font-size: 0.9rem;
}

.card-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.65rem;
}

.card-item-main {
  flex-direction: column;
  align-items: flex-start;
  gap: 0.35rem;
}

.card-front-preview {
  font-weight: 600;
}

.card-back-preview {
  color: var(--ink-muted);
  font-size: 0.92rem;
}

.study-page {
  display: flex;
  flex-direction: column;
  min-height: 100dvh;
  padding-bottom: calc(1.5rem + env(safe-area-inset-bottom));
}

.study-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.25rem;
}

.study-progress {
  font-size: 0.85rem;
  color: var(--ink-muted);
}

.flashcard {
  position: relative;
  flex: 1;
  min-height: 280px;
  width: 100%;
  margin-bottom: 1.25rem;
  border: 1px solid var(--line);
  border-radius: 28px;
  background:
    linear-gradient(160deg, rgba(243, 239, 230, 0.14), rgba(243, 239, 230, 0.05)),
    rgba(12, 46, 42, 0.55);
  box-shadow: var(--shadow);
  overflow: hidden;
  perspective: 1200px;
  transition: transform 0.25s ease;
  animation: card-enter 0.45s ease both;
}

@keyframes card-enter {
  from {
    opacity: 0;
    transform: translateY(24px) scale(0.98);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

.flashcard:active {
  transform: scale(0.985);
}

.flashcard-face {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 0.75rem;
  padding: 2rem 1.5rem;
  transition: opacity 0.28s ease, transform 0.28s ease;
}

.flashcard-front {
  opacity: 1;
  transform: translateY(0);
}

.flashcard-back {
  opacity: 0;
  transform: translateY(12px);
  pointer-events: none;
}

.flashcard.is-flipped .flashcard-front {
  opacity: 0;
  transform: translateY(-12px);
  pointer-events: none;
}

.flashcard.is-flipped .flashcard-back {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

.flashcard-label {
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
}

.flashcard-text {
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 6vw, 2.4rem);
  font-weight: 500;
  text-align: center;
  line-height: 1.25;
}

.flashcard-hint {
  position: absolute;
  bottom: 1.25rem;
  font-size: 0.8rem;
  color: var(--ink-muted);
}

.rating-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.5rem;
  animation: rise 0.35s ease both;
}

.rating {
  display: grid;
  gap: 0.15rem;
  padding: 0.75rem 0.35rem;
  border-radius: 14px;
  font-size: 0.85rem;
}

.rating-label {
  font-weight: 600;
}

.rating-interval {
  font-size: 0.72rem;
  opacity: 0.8;
}

.rating-again {
  background: rgba(231, 111, 81, 0.22);
  border-color: rgba(231, 111, 81, 0.45);
}

.rating-hard {
  background: rgba(233, 196, 106, 0.18);
  border-color: rgba(233, 196, 106, 0.4);
}

.rating-good {
  background: rgba(42, 157, 143, 0.22);
  border-color: rgba(42, 157, 143, 0.45);
}

.rating-easy {
  background: rgba(142, 202, 230, 0.18);
  border-color: rgba(142, 202, 230, 0.4);
}

.reveal {
  width: 100%;
}

.study-done {
  justify-content: center;
  text-align: center;
  gap: 0.75rem;
}

.editor-page .editor-form {
  margin-top: 0.5rem;
}

.top-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin-bottom: 0.5rem;
}

.top-bar .brand-mark {
  font-size: clamp(2rem, 6vw, 2.8rem);
}

.auth-page {
  padding-top: 3rem;
}

.form-error {
  margin: 0;
  color: #ffb4a2;
  font-size: 0.9rem;
}

.import-msg {
  margin: 0.85rem 0 0;
  color: var(--accent);
}

.hint-line {
  margin: 0.65rem 0 0;
  color: var(--ink-muted);
  font-size: 0.85rem;
}

.hint-line code {
  font-family: ui-monospace, monospace;
  font-size: 0.8em;
}

a.deck-main,
a.btn {
  text-decoration: none;
  color: inherit;
}

a.btn-primary {
  color: #1a1a12;
}

a.btn-study {
  color: #04201c;
  display: inline-flex;
  align-items: center;
}

a.is-disabled {
  opacity: 0.45;
  pointer-events: none;
}

.card-item-main.static {
  cursor: default;
}

.card-item-main.static:hover {
  background: var(--surface);
  border-color: var(--line);
}

@media (max-width: 480px) {
  .rating-row {
    grid-template-columns: repeat(2, 1fr);
  }

  .deck-side .btn-study {
    padding-inline: 0.75rem;
    font-size: 0.85rem;
  }

  .top-bar {
    flex-wrap: wrap;
  }
}


.top-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin-bottom: 0.5rem;
}
.top-bar .brand-mark { font-size: clamp(2rem, 6vw, 2.8rem); }
.auth-page { padding-top: 3rem; }
.form-error { margin: 0; color: #ffb4a2; font-size: 0.9rem; }
.flash {
  margin: 0 0 1rem;
  padding: 0.85rem 1rem;
  border-radius: 12px;
  border: 1px solid var(--line);
  background: var(--surface);
}
.flash-ok { border-color: rgba(42, 157, 143, 0.45); color: #9fe0d6; }
.flash-error { border-color: rgba(231, 111, 81, 0.45); color: #ffb4a2; }
a.deck-main, a.btn { text-decoration: none; color: inherit; }
a.btn-primary { color: #1a1a12; }
a.btn-study { color: #04201c; display: inline-flex; align-items: center; }
.card-item-main.static { cursor: default; }
.hint-line { margin: 0.65rem 0 0; color: var(--ink-muted); font-size: 0.85rem; }
.import-box {
  margin: 1rem 0 1.5rem;
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

a.flashcard {
  display: block;
  text-decoration: none;
  color: inherit;
}
.rating-row form { margin: 0; }
.rating-row form .btn { width: 100%; }