/* Inspired by modern dashboard / collapsible sidebar patterns (21st.dev) */
:root {
  --font-display: "Outfit", system-ui, sans-serif;
  --font-body: "DM Sans", system-ui, sans-serif;
  --radius: 14px;
  --radius-sm: 10px;
  --transition: 0.22s ease;
}

[data-theme="light"] {
  --bg-app: #eef1f6;
  --bg-sidebar: #ffffff;
  --bg-card: #ffffff;
  --bg-input: #f0f2f7;
  --border: rgba(15, 23, 42, 0.08);
  --border-strong: rgba(15, 23, 42, 0.12);
  --text: #0f172a;
  --text-muted: #64748b;
  --accent: #2563eb;
  --accent-soft: rgba(37, 99, 235, 0.1);
  --accent-hover: #1d4ed8;
  --success: #059669;
  --success-bg: rgba(5, 150, 105, 0.1);
  --danger: #dc2626;
  --danger-bg: rgba(220, 38, 38, 0.08);
  --shadow: 0 1px 3px rgba(15, 23, 42, 0.06), 0 12px 40px rgba(15, 23, 42, 0.06);
}

[data-theme="dark"] {
  --bg-app: #0c0f14;
  --bg-sidebar: #12161e;
  --bg-card: #161b26;
  --bg-input: #1e2430;
  --border: rgba(248, 250, 252, 0.06);
  --border-strong: rgba(248, 250, 252, 0.1);
  --text: #f1f5f9;
  --text-muted: #94a3b8;
  --accent: #38bdf8;
  --accent-soft: rgba(56, 189, 248, 0.12);
  --accent-hover: #7dd3fc;
  --success: #34d399;
  --success-bg: rgba(52, 211, 153, 0.12);
  --danger: #f87171;
  --danger-bg: rgba(248, 113, 113, 0.1);
  --shadow: 0 1px 0 rgba(255, 255, 255, 0.04) inset, 0 24px 48px rgba(0, 0, 0, 0.35);
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.55;
  color: var(--text);
  background: var(--bg-app);
  transition: background var(--transition), color var(--transition);
}

.app {
  display: block;
  min-height: 100vh;
}

@media (min-width: 1024px) {
  .app {
    display: flex;
    align-items: stretch;
  }
}

/* [hidden] must win over .app display — otherwise the study UI shows below the login card. */
.app[hidden],
#auth-root[hidden] {
  display: none !important;
}

/* Sidebar */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 200;
  width: min(320px, 88vw);
  height: 100vh;
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  padding: 1.25rem 1rem 1rem;
  box-shadow: var(--shadow);
  transform: translateX(-100%);
  transition: transform var(--transition);
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
}

.sidebar.is-open {
  transform: translateX(0);
}

.sidebar-backdrop {
  position: fixed;
  inset: 0;
  z-index: 150;
  background: rgba(0, 0, 0, 0.45);
  backdrop-filter: blur(2px);
}

@media (min-width: 1024px) {
  .sidebar {
    position: relative;
    transform: none;
    flex-shrink: 0;
    height: 100vh;
    width: 280px;
  }
  .sidebar-toggle {
    display: none !important;
  }
  .sidebar-backdrop {
    display: none !important;
  }
}

.sidebar-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding-bottom: 1.25rem;
  margin-bottom: 0.5rem;
  border-bottom: 1px solid var(--border);
}

.sidebar-logo {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: linear-gradient(145deg, var(--accent-soft), transparent);
  display: grid;
  place-items: center;
  font-size: 1.35rem;
  border: 1px solid var(--border);
}

.sidebar-brand-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: -0.02em;
}

.sidebar-brand-sub {
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-top: 0.15rem;
}

/* Sidebar panels (dashboard-style layout) */
.sidebar-panel {
  padding: 1rem 0.85rem;
  margin-bottom: 0.75rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--bg-input);
  box-shadow: 0 1px 0 rgba(255, 255, 255, 0.04) inset;
}

.sidebar-panel--accent {
  border-color: var(--accent-soft);
  background: linear-gradient(165deg, var(--bg-input) 0%, var(--bg-sidebar) 100%);
}

.sidebar-panel-hint {
  font-size: 0.76rem;
  color: var(--text-muted);
  line-height: 1.4;
  margin: 0 0 0.75rem;
}

.sidebar-stat-row {
  display: flex;
  align-items: baseline;
  gap: 0.35rem;
  margin-bottom: 0.75rem;
}

.sidebar-stat-num {
  font-family: var(--font-display);
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--text);
  line-height: 1;
}

.sidebar-stat-label {
  font-size: 0.72rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.sidebar-mini-wrap {
  max-height: 140px;
  overflow: hidden;
  margin-top: 0.5rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--bg-sidebar);
}

.review-list--compact {
  max-height: 140px;
  padding: 4px;
}

.review-list--compact .review-item {
  padding: 0.4rem 0.5rem;
  font-size: 0.78rem;
}

.review-list-more {
  list-style: none;
  padding: 0.45rem 0.5rem;
  font-size: 0.72rem;
  color: var(--text-muted);
  font-style: italic;
}

.sidebar-empty--inline {
  margin: 0.35rem 0 0;
  font-size: 0.78rem;
}

.review-bank-actions {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.btn-block {
  width: 100%;
  justify-content: center;
}

.btn-sm {
  padding: 0.5rem 0.75rem;
  font-size: 0.82rem;
}

.sidebar-section {
  margin-bottom: 1rem;
}

.sidebar-section--grow {
  flex: 1;
  min-height: 0;
  display: flex;
  flex-direction: column;
}

.sidebar-label {
  display: block;
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.sidebar-search-wrap {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.45rem 0.65rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--bg-input);
}

.sidebar-search-icon {
  color: var(--accent);
  opacity: 0.85;
}

.sidebar-search {
  flex: 1;
  border: none;
  background: transparent;
  color: var(--text);
  font: inherit;
  font-size: 0.9rem;
  outline: none;
  min-width: 0;
}

.sidebar-queue-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.text-btn {
  border: none;
  background: none;
  color: var(--accent);
  font: inherit;
  font-size: 0.78rem;
  font-weight: 600;
  cursor: pointer;
  padding: 0.2rem 0.35rem;
  border-radius: 6px;
}

.text-btn:hover {
  background: var(--accent-soft);
}

.review-list {
  list-style: none;
  margin: 0;
  padding: 0;
  overflow-y: auto;
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.review-item {
  width: 100%;
  text-align: left;
  padding: 0.55rem 0.65rem;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  background: transparent;
  color: var(--text);
  font: inherit;
  font-size: 0.82rem;
  cursor: pointer;
  line-height: 1.35;
  transition: background var(--transition), border-color var(--transition);
}

.review-item:hover {
  background: var(--bg-input);
}

.review-item.is-active {
  background: var(--accent-soft);
  border-color: var(--accent);
  color: var(--text);
}

.review-item-title {
  font-weight: 600;
  display: block;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.review-item-sub {
  font-size: 0.72rem;
  color: var(--text-muted);
  margin-top: 0.15rem;
}

.sidebar-empty {
  font-size: 0.82rem;
  color: var(--text-muted);
  line-height: 1.45;
  margin: 0.5rem 0 0;
}

.sidebar-empty[hidden] {
  display: none !important;
}

/* Toggle mobile */
.sidebar-toggle {
  position: fixed;
  top: 1rem;
  left: 1rem;
  z-index: 250;
  width: 44px;
  height: 44px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text);
  cursor: pointer;
  display: grid;
  place-items: center;
  box-shadow: var(--shadow);
}

/* Main */
.main-wrap {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
  padding: 1rem 1rem 2rem;
  padding-top: calc(3.5rem + env(safe-area-inset-top));
}

@media (min-width: 1024px) {
  .main-wrap {
    padding: 1.5rem 2rem 2.5rem;
    padding-top: 1.5rem;
  }
}

.top-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.5rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--border);
}

.top-title {
  font-family: var(--font-display);
  font-size: clamp(1.35rem, 3vw, 1.75rem);
  font-weight: 700;
  margin: 0;
  letter-spacing: -0.03em;
}

.top-sub {
  margin: 0.35rem 0 0;
  font-size: 0.92rem;
  color: var(--text-muted);
  max-width: 42ch;
}

.top-bar-right {
  display: flex;
  flex-wrap: nowrap;
  align-items: center;
  gap: 0.5rem;
  flex: 1 1 auto;
  min-width: 0;
  justify-content: flex-end;
}

.top-bar-right .btn-compact {
  flex-shrink: 0;
}

.top-bar-right .account-wrap {
  flex-shrink: 0;
}

.global-search-wrap {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--bg-input);
  flex: 1 1 auto;
  min-width: 0;
  max-width: min(22rem, 100%);
}

.global-search-icon {
  color: var(--accent);
  flex-shrink: 0;
}

.global-search {
  border: none;
  background: transparent;
  color: var(--text);
  font: inherit;
  font-size: 0.9rem;
  width: 100%;
  min-width: 0;
  outline: none;
}

.theme-toggle {
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text);
  cursor: pointer;
  display: grid;
  place-items: center;
  font-size: 1.1rem;
  position: relative;
}

.theme-icon {
  position: absolute;
  transition: opacity var(--transition), transform var(--transition);
}

[data-theme="light"] .theme-icon--moon {
  opacity: 0;
  transform: scale(0.5);
}
[data-theme="light"] .theme-icon--sun {
  opacity: 1;
}

[data-theme="dark"] .theme-icon--sun {
  opacity: 0;
  transform: scale(0.5);
}
[data-theme="dark"] .theme-icon--moon {
  opacity: 1;
}

.main-stage {
  max-width: 800px;
  margin: 0 auto;
  width: 100%;
}

.load-error {
  padding: 1.25rem;
  border-radius: var(--radius);
  background: var(--danger-bg);
  color: var(--danger);
  font-weight: 600;
}

.q-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.65rem 1.5rem;
  box-shadow: var(--shadow);
}

[data-theme="light"] .q-card {
  box-shadow: var(--shadow), 0 0 0 1px rgba(255, 255, 255, 0.5) inset;
}

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

.q-badge {
  font-family: var(--font-display);
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.02em;
}

.q-meta {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.q-text {
  font-size: 1.08rem;
  font-weight: 600;
  line-height: 1.5;
  margin: 0 0 1.25rem;
}

.q-options {
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
}

.opt {
  display: flex;
  align-items: flex-start;
  gap: 0.65rem;
  width: 100%;
  text-align: left;
  padding: 0.85rem 1rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--bg-app);
  color: var(--text);
  font: inherit;
  font-size: 0.95rem;
  cursor: pointer;
  transition: border-color var(--transition), background var(--transition), box-shadow var(--transition);
}

.opt:hover:not(:disabled) {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent-soft);
}

.opt:disabled {
  cursor: default;
}

.opt-letter {
  flex-shrink: 0;
  font-weight: 700;
  font-size: 0.8rem;
  width: 1.6rem;
  height: 1.6rem;
  display: grid;
  place-items: center;
  border-radius: 8px;
  background: var(--bg-input);
  color: var(--accent);
}

.opt.is-selected {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.opt.is-correct {
  border-color: var(--success);
  background: var(--success-bg);
}

.opt.is-wrong {
  border-color: var(--danger);
  background: var(--danger-bg);
}

.q-options--multi .opt.is-selected {
  box-shadow: 0 0 0 2px var(--accent);
}

.q-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem 0.65rem;
  margin-top: 1.35rem;
  align-items: center;
  justify-content: center;
}

.btn {
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 600;
  padding: 0.65rem 1.15rem;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition), opacity var(--transition);
}

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

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

[data-theme="dark"] .btn-primary {
  color: #0c1220;
}

.btn-primary:hover:not(:disabled) {
  filter: brightness(1.08);
}

.btn-secondary {
  background: var(--bg-input);
  color: var(--text);
  border-color: var(--border);
}

.btn-secondary:hover:not(:disabled) {
  border-color: var(--accent);
}

.btn-secondary.is-on {
  background: var(--accent-soft);
  border-color: var(--accent);
  color: var(--accent);
}

.btn-outline {
  background: transparent;
  color: var(--text);
  border-color: var(--border);
}

.btn-outline:hover:not(:disabled) {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.q-actions #btn-next.btn-outline {
  border-color: var(--accent);
  color: var(--accent);
}

.q-actions #btn-next.btn-outline:hover:not(:disabled) {
  background: var(--accent-soft);
}

.btn-nav-plain {
  background: transparent;
  border: 1px solid transparent;
  color: var(--text);
  font-weight: 600;
}

.btn-nav-plain:hover:not(:disabled) {
  color: var(--accent);
}

.btn-nav-plain.is-on {
  color: var(--accent);
}

.q-result {
  margin-top: 1.25rem;
  padding: 1rem 1.1rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-strong);
  background: var(--bg-input);
}

.q-result-row {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.5rem;
}

.q-result-label {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
}

.q-result-value {
  font-family: var(--font-display);
  font-size: 1.15rem;
  color: var(--success);
}

.q-result-hint {
  margin: 0.5rem 0 0;
  font-size: 0.88rem;
  color: var(--text-muted);
}

.q-nav-pos {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
  min-width: 6.5rem;
  text-align: center;
  flex-shrink: 0;
  padding: 0 0.15rem;
}

@media (min-width: 720px) {
  .q-actions {
    flex-wrap: nowrap;
    justify-content: space-between;
    gap: 0.75rem;
  }
}

.q-doc-strip {
  margin-top: 1rem;
  padding: 0.85rem 1rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--bg-card);
}

.q-doc-strip-lead {
  margin: 0 0 0.45rem;
  font-size: 0.82rem;
  color: var(--text-muted);
  line-height: 1.45;
}

.q-doc-link {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--accent);
  text-decoration: none;
  word-break: break-word;
}

.q-doc-link:hover {
  text-decoration: underline;
}

.btn-compact {
  padding: 0.5rem 0.85rem;
  font-size: 0.85rem;
}

.study-session-bar {
  max-width: 800px;
  margin: 0 auto 1rem;
  width: 100%;
  padding: 0 1rem;
}

@media (min-width: 1024px) {
  .study-session-bar {
    padding: 0 2rem;
  }
}

.study-session-bar-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem 1rem;
  padding: 0.65rem 1rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--bg-card);
  box-shadow: var(--shadow);
}

.study-session-label {
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--accent);
}

.study-session-score {
  font-size: 0.88rem;
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
}

.global-search-wrap.is-disabled {
  opacity: 0.45;
  pointer-events: none;
}

.q-result-score-note {
  margin: 0.65rem 0 0;
  font-size: 0.82rem;
  color: var(--accent);
  line-height: 1.45;
}

/* Modals (study) */
.modal-overlay {
  position: fixed;
  inset: 0;
  z-index: 500;
  background: rgba(15, 23, 42, 0.55);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}

.modal-overlay[hidden] {
  display: none !important;
}

.modal-card {
  width: 100%;
  max-width: 420px;
  border-radius: var(--radius);
  padding: 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  color: var(--text);
}

.modal-card--study .modal-title {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  margin: 0 0 0.75rem;
}

.modal-desc {
  margin: 0 0 1rem;
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.45;
}

.modal-field {
  margin-bottom: 1rem;
}

.modal-label {
  display: block;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  margin-bottom: 0.4rem;
}

.modal-input {
  width: 100%;
  padding: 0.65rem 0.85rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--bg-input);
  color: var(--text);
  font: inherit;
  font-size: 1rem;
}

.modal-hint {
  margin: 0 0 1.25rem;
  font-size: 0.82rem;
  color: var(--text-muted);
  line-height: 1.45;
}

.modal-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  justify-content: flex-end;
}

.modal-summary-body {
  font-size: 0.95rem;
  line-height: 1.55;
  margin-bottom: 1.25rem;
}

.modal-summary-body strong {
  color: var(--accent);
}

.modal-score-big {
  text-align: center;
  margin: 0 0 1rem;
  font-variant-numeric: tabular-nums;
  line-height: 1.35;
}

.modal-score-num {
  font-size: 1.85rem;
  color: var(--success);
}

.modal-score-sep {
  font-size: 1.35rem;
  color: var(--text-muted);
  font-weight: 600;
}

.modal-score-den {
  font-size: 1.85rem;
  color: var(--text);
}

.modal-score-caption {
  display: block;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--text-muted);
  margin-top: 0.4rem;
}

.session-wrong-list {
  max-height: min(28vh, 220px);
}