:root {
  color-scheme: dark;
  --bg: #07111f;
  --panel: rgba(15, 23, 42, 0.78);
  --panel-strong: rgba(15, 23, 42, 0.94);
  --border: rgba(255, 255, 255, 0.16);
  --border-strong: rgba(255, 255, 255, 0.3);
  --text: #f8fafc;
  --muted: #cbd5e1;
  --soft: #94a3b8;
  --cyan: #67e8f9;
  --teal: #2dd4bf;
  --yellow: #fde68a;
  --pink: #f9a8d4;
  --green: #86efac;
  --blue: #93c5fd;
  --shadow: 0 28px 100px rgba(2, 8, 23, 0.42);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
  background: var(--bg);
}

body {
  min-height: 100svh;
  margin: 0;
  background:
    linear-gradient(180deg, rgba(8, 17, 31, 0.18), rgba(8, 17, 31, 0.88)),
    url("assets/cover.png") center top / cover fixed no-repeat,
    var(--bg);
  color: var(--text);
}

button,
input,
select {
  font: inherit;
}

button,
select {
  cursor: pointer;
}

button:disabled {
  cursor: not-allowed;
}

button:focus-visible,
input:focus-visible,
select:focus-visible {
  outline: 3px solid rgba(103, 232, 249, 0.72);
  outline-offset: 2px;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

.app-shell {
  width: min(1120px, 100%);
  min-height: 100svh;
  margin: 0 auto;
  padding:
    max(18px, env(safe-area-inset-top))
    max(14px, env(safe-area-inset-right))
    max(26px, env(safe-area-inset-bottom))
    max(14px, env(safe-area-inset-left));
}

.view {
  min-height: calc(100svh - max(18px, env(safe-area-inset-top)) - max(26px, env(safe-area-inset-bottom)));
  animation: view-in 220ms ease both;
}

.view:not(.is-active),
[hidden] {
  display: none !important;
}

.cover-view {
  display: grid;
  place-items: center;
}

.cover-card,
.panel,
.word-card {
  border: 1px solid var(--border);
  background: var(--panel);
  box-shadow: var(--shadow);
  backdrop-filter: blur(22px);
}

.cover-card {
  width: min(760px, 100%);
  padding: clamp(30px, 7vw, 70px);
  border-radius: 44px;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.cover-card::before,
.panel::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 12% 18%, rgba(45, 212, 191, 0.24), transparent 32%),
    radial-gradient(circle at 88% 12%, rgba(147, 197, 253, 0.18), transparent 34%);
  pointer-events: none;
}

.cover-card > *,
.panel > * {
  position: relative;
  z-index: 1;
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--cyan);
  font-size: 0.78rem;
  font-weight: 900;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

h1 {
  margin-bottom: 18px;
  font-size: clamp(3.4rem, 13vw, 8rem);
  font-weight: 950;
  line-height: 0.9;
  letter-spacing: -0.08em;
}

h2 {
  margin-bottom: 0;
  font-size: clamp(1.8rem, 5vw, 3.4rem);
  font-weight: 900;
  line-height: 1;
  letter-spacing: -0.05em;
}

h3 {
  margin-bottom: 8px;
}

.cover-lead {
  max-width: 620px;
  margin: 0 auto 28px;
  color: #e0f2fe;
  font-size: clamp(1.05rem, 3vw, 1.35rem);
  line-height: 1.55;
}

.cover-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin: 0 0 28px;
}

.cover-stats div,
.progress-box,
.setup-summary,
.preview-chip,
.translation-card,
.word-note {
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.09);
}

.cover-stats div {
  padding: 16px 12px;
  border-radius: 24px;
}

.cover-stats strong {
  display: block;
  font-size: clamp(1.5rem, 5vw, 2.4rem);
  line-height: 1;
}

.cover-stats span {
  display: block;
  margin-top: 7px;
  color: var(--muted);
  font-size: 0.86rem;
  font-weight: 750;
}

.flow-view,
.study-view {
  display: grid;
  align-content: start;
  gap: 16px;
}

.top-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
}

.panel {
  position: relative;
  overflow: hidden;
  border-radius: 36px;
  padding: clamp(20px, 5vw, 42px);
}

.setup-panel {
  min-height: min(700px, calc(100svh - 112px));
  display: grid;
  align-content: start;
  gap: 22px;
}

.section-heading {
  display: flex;
  gap: 18px;
  align-items: flex-start;
  justify-content: space-between;
}

.step-pill,
.session-count {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 40px;
  padding: 0 14px;
  border: 1px solid rgba(103, 232, 249, 0.28);
  border-radius: 999px;
  background: rgba(8, 47, 73, 0.38);
  color: #e0f2fe;
  font-size: 0.86rem;
  font-weight: 850;
}

.primary-button,
.secondary-button,
.ghost-button,
.back-button,
.mode-switch__button,
.card-button,
.reveal-button,
.speak-button {
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--text);
  font-weight: 850;
  transition:
    transform 160ms ease,
    border-color 160ms ease,
    background 160ms ease,
    color 160ms ease,
    opacity 160ms ease;
}

.primary-button:hover:not(:disabled),
.secondary-button:hover:not(:disabled),
.ghost-button:hover:not(:disabled),
.back-button:hover:not(:disabled),
.mode-switch__button:hover:not(:disabled),
.card-button:hover:not(:disabled),
.reveal-button:hover:not(:disabled),
.speak-button:hover:not(:disabled) {
  transform: translateY(-1px);
}

.primary-button {
  min-height: 54px;
  padding: 0 24px;
  border-color: rgba(103, 232, 249, 0.5);
  background: linear-gradient(135deg, rgba(45, 212, 191, 0.96), rgba(96, 165, 250, 0.96));
  color: #07111f;
  box-shadow: 0 18px 50px rgba(45, 212, 191, 0.2);
}

.secondary-button,
.ghost-button,
.back-button,
.card-button,
.reveal-button,
.speak-button {
  background: rgba(255, 255, 255, 0.1);
}

.secondary-button,
.ghost-button,
.back-button,
.reveal-button {
  min-height: 46px;
  padding: 0 16px;
}

.back-button {
  color: #e0f2fe;
}

.ghost-button {
  color: var(--muted);
}

.primary-button:disabled,
.secondary-button:disabled,
.speak-button:disabled,
.is-disabled {
  opacity: 0.48;
  transform: none;
}

.mode-switch {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  padding: 6px;
  border: 1px solid var(--border);
  border-radius: 28px;
  background: rgba(2, 6, 23, 0.3);
}

.mode-switch__button {
  min-height: 56px;
  padding: 0 18px;
  background: transparent;
  color: var(--muted);
}

.mode-switch__button.is-active {
  background: linear-gradient(135deg, rgba(45, 212, 191, 0.95), rgba(96, 165, 250, 0.95));
  color: #07111f;
}

.control-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.vocabulary-controls {
  grid-template-columns: minmax(0, 2fr) minmax(180px, 0.7fr);
}

.field {
  display: grid;
  gap: 8px;
}

.field--wide {
  grid-column: span 2;
}

.field span {
  color: var(--muted);
  font-size: 0.85rem;
  font-weight: 850;
}

.field select,
.field input {
  width: 100%;
  min-height: 50px;
  border: 1px solid var(--border);
  border-radius: 18px;
  background: rgba(2, 6, 23, 0.58);
  color: var(--text);
  padding: 0 14px;
}

.field input::placeholder {
  color: rgba(203, 213, 225, 0.64);
}

.setup-summary {
  padding: 14px 16px;
  border-radius: 20px;
  color: #e0f2fe;
  line-height: 1.45;
}

.action-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px;
  margin-top: auto;
}

.word-preview {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 230px), 1fr));
  gap: 10px;
}

.preview-chip {
  display: grid;
  gap: 6px;
  min-height: 76px;
  padding: 14px;
  border-radius: 20px;
}

.preview-chip span {
  color: var(--text);
  font-weight: 850;
  line-height: 1.35;
}

.preview-chip small {
  color: var(--soft);
  font-weight: 750;
  text-transform: capitalize;
}

.preview-chip--more {
  place-items: center;
  color: var(--cyan);
  font-weight: 900;
}

.empty-state {
  padding: 36px 20px;
  border: 1px dashed var(--border-strong);
  border-radius: 24px;
  text-align: center;
}

.empty-state p {
  margin-bottom: 0;
  color: var(--muted);
}

.study-layout {
  display: grid;
  gap: 16px;
}

.study-header,
.study-controls {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}

.study-header h2 {
  font-size: clamp(1.5rem, 4vw, 2.4rem);
}

.progress-box {
  display: grid;
  gap: 10px;
  width: min(320px, 100%);
  padding: 14px;
  border-radius: 22px;
  color: #e0f2fe;
  font-weight: 850;
}

.progress-track {
  height: 10px;
  overflow: hidden;
  border-radius: 999px;
  background: rgba(2, 6, 23, 0.55);
}

.progress-fill {
  width: 0%;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--teal), var(--blue));
  transition: width 180ms ease;
}

.study-card-host {
  min-height: 480px;
  display: grid;
}

.word-card {
  display: grid;
  gap: 18px;
  width: 100%;
  border-radius: 36px;
  padding: clamp(18px, 4vw, 34px);
  background: var(--panel-strong);
}

.word-card.is-nudged {
  animation: card-nudge 260ms ease;
}

.word-card__header {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  justify-content: space-between;
}

.word-card__meta,
.word-card__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.word-card__actions {
  justify-content: flex-end;
}

.badge {
  display: inline-flex;
  align-items: center;
  min-height: 28px;
  padding: 5px 10px;
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--muted);
  background: rgba(255, 255, 255, 0.08);
  font-size: 0.75rem;
  font-weight: 850;
  text-transform: capitalize;
}

.card-button {
  min-width: 42px;
  min-height: 38px;
  padding: 0 10px;
  color: var(--muted);
}

.card-button.is-active[data-action="favorite"] {
  border-color: rgba(253, 230, 138, 0.72);
  background: rgba(253, 230, 138, 0.18);
  color: var(--yellow);
}

.card-button.is-active[data-action="mastered"] {
  border-color: rgba(134, 239, 172, 0.72);
  background: rgba(134, 239, 172, 0.16);
  color: var(--green);
}

.translation-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 12px;
}

body[data-mode="three"] .translation-list {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.translation-card {
  min-height: 230px;
  border-radius: 28px;
  overflow: hidden;
}

.translation-card__inner {
  display: grid;
  gap: 12px;
  height: 100%;
  padding: clamp(16px, 3vw, 22px);
}

.translation-card__topline {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.language-label {
  color: var(--cyan);
  font-size: 0.74rem;
  font-weight: 950;
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

.speak-button {
  display: inline-grid;
  place-items: center;
  width: 42px;
  min-width: 42px;
  height: 42px;
  padding: 0;
  background: rgba(103, 232, 249, 0.14);
  color: #e0f2fe;
  font-size: 1rem;
}

.speak-button:hover:not(:disabled) {
  border-color: rgba(103, 232, 249, 0.58);
  background: rgba(103, 232, 249, 0.24);
}

.translation-text {
  margin: 0;
  font-size: clamp(2.2rem, 8vw, 4.2rem);
  font-weight: 950;
  line-height: 1.02;
  overflow-wrap: anywhere;
}

.translation-card[data-lang="fi"] .translation-text {
  color: var(--green);
}

.translation-card[data-lang="zh"] .translation-text {
  color: var(--pink);
}

.translation-example,
.translation-pinyin,
.translation-forms,
.word-note {
  margin: 0;
  color: var(--muted);
  line-height: 1.45;
}

.translation-pinyin,
.translation-forms {
  font-size: 0.9rem;
}

.translation-forms strong,
.word-note strong {
  color: #e0f2fe;
}

.translation-card.is-hidden .translation-card__inner {
  place-content: center;
  text-align: center;
}

.hidden-word {
  margin: 0;
  color: var(--soft);
  font-size: 1rem;
  font-weight: 850;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.reveal-button {
  justify-self: center;
  border-color: rgba(103, 232, 249, 0.42);
  background: rgba(103, 232, 249, 0.16);
  color: #e0f2fe;
}

.word-note {
  padding: 14px 16px;
  border-radius: 20px;
  background: rgba(14, 116, 144, 0.12);
}

.study-controls {
  position: sticky;
  bottom: max(14px, env(safe-area-inset-bottom));
  z-index: 5;
}

.study-controls .secondary-button {
  flex: 1;
}

@keyframes card-nudge {
  0%,
  100% {
    transform: translateX(0);
  }
  35% {
    transform: translateX(-6px);
  }
  70% {
    transform: translateX(6px);
  }
}

@keyframes view-in {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 900px) {
  body {
    background-attachment: scroll;
  }

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

  .field--wide {
    grid-column: span 2;
  }

  body[data-mode="three"] .translation-list {
    grid-template-columns: 1fr;
  }

  .study-header,
  .study-controls {
    align-items: stretch;
    flex-direction: column;
  }

  .progress-box {
    width: 100%;
  }
}

@media (max-width: 620px) {
  .app-shell {
    padding-inline: max(12px, env(safe-area-inset-left));
  }

  .cover-card,
  .panel,
  .word-card {
    border-radius: 28px;
  }

  h1 {
    letter-spacing: -0.06em;
  }

  .cover-stats,
  .control-grid,
  .vocabulary-controls,
  .mode-switch {
    grid-template-columns: 1fr;
  }

  .field--wide {
    grid-column: auto;
  }

  .section-heading,
  .word-card__header,
  .top-bar {
    align-items: stretch;
    flex-direction: column;
  }

  .action-row {
    flex-direction: column;
  }

  .word-card__actions {
    justify-content: flex-start;
  }

  .translation-card {
    min-height: 210px;
  }
}