:root {
  color-scheme: light;
  --ink: #17212b;
  --muted: #64748b;
  --line: #d9e2ec;
  --paper: #fffdf8;
  --panel: #f7fafc;
  --navy: #102a43;
  --teal: #2bb3a3;
  --gold: #f6c85f;
  --coral: #d95d59;
  --green: #2f855a;
  --shadow: 0 20px 60px rgba(16, 42, 67, 0.14);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    linear-gradient(135deg, rgba(246, 200, 95, 0.22), transparent 34%),
    linear-gradient(180deg, #eef7f5 0%, #fffdf8 54%, #f8fafc 100%);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

body,
html {
  overflow-x: hidden;
}

button,
input {
  font: inherit;
}

button {
  cursor: pointer;
}

.app-shell {
  display: grid;
  grid-template-columns: clamp(300px, 25vw, 390px) minmax(0, 1fr);
  min-height: 100vh;
  width: min(100%, 1680px);
  margin: 0 auto;
}

.sidebar {
  border-right: 1px solid var(--line);
  background: rgba(255, 253, 248, 0.88);
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 18px;
  min-height: 100vh;
  max-height: 100vh;
  position: sticky;
  top: 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand h1 {
  margin: 0;
  font-size: 1.35rem;
  letter-spacing: 0;
}

.brand p {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.search-box {
  display: grid;
  gap: 7px;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 700;
  text-transform: uppercase;
}

.search-box input,
.answer-row input {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: white;
  color: var(--ink);
  outline: none;
}

.search-box input {
  padding: 12px 13px;
}

.answer-row input {
  padding: 14px 15px;
  font-size: 1.04rem;
}

.search-box input:focus,
.answer-row input:focus {
  border-color: var(--teal);
  box-shadow: 0 0 0 3px rgba(43, 179, 163, 0.16);
}

.segmented,
.sidebar-actions {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 6px;
}

.mode-btn,
.small-btn,
.primary-btn,
.secondary-btn {
  min-height: 40px;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: white;
  color: var(--ink);
  font-weight: 750;
}

.mode-btn.is-active,
.small-btn[aria-pressed="true"] {
  background: var(--navy);
  border-color: var(--navy);
  color: white;
}

.small-btn.quiet {
  color: var(--muted);
}

.category-header {
  display: flex;
  justify-content: space-between;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 800;
  text-transform: uppercase;
}

.category-list {
  display: grid;
  gap: 8px;
  overflow: auto;
  padding-right: 4px;
  min-height: 0;
}

.category-item {
  display: grid;
  grid-template-columns: 18px minmax(0, 1fr) auto;
  gap: 10px;
  align-items: center;
  min-height: 44px;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 9px 10px;
  background: rgba(255, 255, 255, 0.72);
}

.category-item input {
  accent-color: var(--teal);
}

.category-item span {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  font-weight: 700;
}

.category-item strong {
  color: var(--muted);
  font-size: 0.82rem;
}

.practice {
  width: min(100%, 1120px);
  margin: 0 auto;
  padding: clamp(24px, 4vw, 56px);
  display: grid;
  align-content: center;
  gap: 18px;
}

.stats-grid,
.review-strip {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}

.review-strip {
  grid-template-columns: repeat(2, 1fr);
}

.stats-grid div,
.review-strip div {
  min-height: 74px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.74);
  padding: 14px;
}

.stats-grid span,
.review-strip span {
  display: block;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 800;
  text-transform: uppercase;
}

.stats-grid strong,
.review-strip strong {
  display: block;
  margin-top: 7px;
  font-size: 1.45rem;
}

.practice-card {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--paper);
  box-shadow: var(--shadow);
  padding: clamp(22px, 4vw, 42px);
  min-height: 520px;
  display: grid;
  gap: 20px;
  align-content: start;
}

.card-topline {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 850;
  text-transform: uppercase;
}

.subcategory {
  min-height: 24px;
  margin: 0;
  color: var(--teal);
  font-weight: 850;
  text-transform: uppercase;
}

.question {
  min-height: 150px;
  font-size: clamp(1.65rem, 2.2vw, 2.7rem);
  line-height: 1.16;
  font-weight: 850;
  display: flex;
  align-items: center;
}

.answer-form {
  display: grid;
  gap: 8px;
}

.answer-form label {
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 800;
  text-transform: uppercase;
}

.answer-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 110px;
  gap: 8px;
}

.primary-btn {
  border-color: var(--navy);
  background: var(--navy);
  color: white;
  padding: 0 18px;
}

.secondary-btn {
  padding: 0 16px;
}

.secondary-btn.success {
  border-color: rgba(47, 133, 90, 0.35);
  color: var(--green);
}

.secondary-btn.danger {
  border-color: rgba(217, 93, 89, 0.35);
  color: var(--coral);
}

.choice-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.choice-grid button {
  min-height: 58px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: white;
  color: var(--ink);
  padding: 12px;
  text-align: left;
  font-weight: 750;
}

.choice-grid button.correct {
  border-color: rgba(47, 133, 90, 0.45);
  background: rgba(47, 133, 90, 0.1);
}

.choice-grid button.wrong {
  border-color: rgba(217, 93, 89, 0.45);
  background: rgba(217, 93, 89, 0.1);
}

.answer-panel {
  border-left: 5px solid var(--gold);
  background: #fff8e6;
  padding: 14px 16px;
}

.answer-panel span {
  display: block;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 850;
  text-transform: uppercase;
}

.answer-panel strong {
  display: block;
  margin-top: 5px;
  font-size: 1.26rem;
}

.feedback {
  border-radius: 8px;
  padding: 12px 14px;
  font-weight: 800;
}

.feedback.good {
  background: rgba(47, 133, 90, 0.1);
  color: var(--green);
}

.feedback.bad {
  background: rgba(217, 93, 89, 0.1);
  color: var(--coral);
}

.card-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 9px;
}

.card-actions button {
  min-width: 104px;
}

@media (min-width: 1280px) {
  .stats-grid,
  .review-strip {
    gap: 14px;
  }

  .practice-card {
    min-height: 560px;
  }
}

@media (max-width: 1180px) {
  .app-shell {
    grid-template-columns: 320px minmax(0, 1fr);
  }

  .practice {
    padding: 24px;
  }

  .question {
    font-size: clamp(1.45rem, 2.4vw, 2.25rem);
  }
}

@media (max-width: 900px) {
  .app-shell {
    grid-template-columns: 1fr;
    width: 100%;
  }

  .sidebar {
    position: static;
    max-height: none;
    min-height: auto;
    border-right: 0;
    border-bottom: 1px solid var(--line);
    display: grid;
    grid-template-columns: minmax(220px, 1.15fr) minmax(240px, 1fr);
    gap: 14px;
    align-items: start;
  }

  .brand,
  .toolbar-row,
  .segmented,
  .sidebar-actions {
    min-width: 0;
  }

  .toolbar-row {
    grid-column: 2;
    grid-row: 1;
  }

  .segmented {
    grid-column: 1;
    grid-row: 2;
  }

  .sidebar-actions {
    grid-column: 2;
    grid-row: 2;
  }

  .category-header,
  .category-list {
    grid-column: 1 / -1;
  }

  .category-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    max-height: 220px;
  }

  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .practice {
    align-content: start;
    width: min(100%, 820px);
  }

  .practice-card {
    min-height: 460px;
  }
}

@media (max-width: 620px) {
  .sidebar {
    display: flex;
    padding: 18px;
  }

  .brand img {
    width: 40px;
    height: 40px;
  }

  .brand h1 {
    font-size: 1.18rem;
  }

  .segmented,
  .sidebar-actions {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .category-list {
    grid-template-columns: 1fr;
    max-height: 220px;
  }

  .practice {
    padding: 16px;
    gap: 14px;
  }

  .answer-row,
  .choice-grid,
  .review-strip {
    grid-template-columns: 1fr;
  }

  .question {
    min-height: 170px;
    font-size: clamp(1.35rem, 8vw, 1.85rem);
  }

  .practice-card {
    min-height: auto;
    padding: 18px;
    gap: 16px;
  }

  .card-topline {
    align-items: flex-start;
    flex-direction: column;
    gap: 6px;
  }

  .stats-grid div,
  .review-strip div {
    min-height: 64px;
    padding: 12px;
  }

  .stats-grid strong,
  .review-strip strong {
    font-size: 1.22rem;
  }

  .card-actions {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .card-actions button {
    min-width: 0;
  }
}