/* Global reset and defaults */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html,
body {
  height: 100%;
  font-family: var(--font-family-base);
  color: var(--color-text-strong);
  background: var(--color-surface-app);
}

body {
  line-height: 1.5;
}

button,
input,
textarea {
  font: inherit;
}

button {
  background: none;
  border: none;
}

[hidden] {
  display: none !important;
}

/* Shared top navigation */
.top-nav {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(255, 255, 255, 0.94);
  border-bottom: 1px solid var(--color-border-card);
  backdrop-filter: blur(10px);
}

.top-nav__inner {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  width: 100%;
  max-width: 1180px;
  min-height: 72px;
  margin: 0 auto;
  padding: var(--space-3) var(--space-6);
}

.top-nav__brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  color: var(--color-text-strong);
  text-decoration: none;
}

.top-nav__mark {
  flex: 0 0 auto;
}

.top-nav__wordmark {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.top-nav__name {
  font-size: 18px;
  font-weight: 900;
}

.top-nav__tagline {
  font-size: 11px;
  font-weight: 700;
  color: var(--color-text-muted);
}

.top-nav__links {
  display: flex;
  align-items: center;
  gap: var(--space-5);
  margin-left: auto;
}

.top-nav__links a,
.top-nav__link {
  color: var(--color-text-muted);
  font-size: 14px;
  font-weight: 800;
  line-height: 1;
  text-decoration: none;
}

.top-nav__actions .top-nav__link,
.top-nav__user {
  display: inline-flex;
  align-items: center;
  min-height: calc(1em + var(--space-4) + (var(--border-width-soft) * 2));
}

.top-nav__text-button {
  justify-content: center;
  background: transparent;
  border: 0;
  cursor: pointer;
  padding: 0;
}

.top-nav__text-button:disabled {
  cursor: not-allowed;
  opacity: 0.55;
}

.top-nav__links a:hover,
.top-nav__link:hover {
  color: var(--color-text-strong);
}

.top-nav__actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  min-width: calc(var(--space-unit) * 34);
  justify-content: flex-end;
}

.top-nav__auth-placeholder {
  display: inline-flex;
  width: calc(var(--space-unit) * 25);
  height: calc(var(--space-unit) * 10);
  border-radius: var(--radius-pill);
  background: var(--color-surface-soft);
  opacity: 0.7;
}

.top-nav__button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: var(--border-width-soft) solid transparent;
  border-radius: var(--radius-pill);
  padding: var(--space-2) var(--space-4);
  font-size: 13px;
  font-weight: 900;
  line-height: 1;
  text-decoration: none;
  cursor: pointer;
  transition:
    transform var(--transition-fast),
    box-shadow var(--transition-fast),
    background var(--transition-base),
    color var(--transition-base);
}

.top-nav__button--primary {
  background: var(--color-primary-600);
  color: var(--color-surface-card);
  box-shadow: var(--shadow-primary);
}

.top-nav__button--primary:hover {
  transform: translate(-1px, -1px);
  box-shadow: calc(var(--space-1) + 1px) calc(var(--space-1) + 1px) 0 var(--color-primary-800);
}

.top-nav__button[aria-disabled="true"] {
  cursor: not-allowed;
  opacity: 0.55;
  transform: none;
}

.top-nav__button[aria-disabled="true"]:hover {
  box-shadow: var(--shadow-primary);
}

.top-nav__button--ghost {
  background: var(--color-surface-card);
  border-color: var(--color-border-card);
  color: var(--color-text-muted);
}

.top-nav__button--ghost:hover {
  background: var(--color-surface-soft);
  color: var(--color-text-strong);
}

.top-nav__menu-button {
  display: none;
  align-items: center;
  justify-content: center;
  width: calc(var(--space-unit) * 10);
  height: calc(var(--space-unit) * 10);
  border: var(--border-width-soft) solid var(--color-border-card);
  border-radius: var(--radius-pill);
  background: var(--color-surface-card);
  color: var(--color-text-strong);
  cursor: pointer;
}

.top-nav__menu-bars,
.top-nav__menu-bars::before,
.top-nav__menu-bars::after {
  display: block;
  width: calc(var(--space-unit) * 4.5);
  height: 2px;
  border-radius: var(--radius-pill);
  background: currentColor;
}

.top-nav__menu-bars {
  position: relative;
}

.top-nav__menu-bars::before,
.top-nav__menu-bars::after {
  position: absolute;
  left: 0;
  content: "";
}

.top-nav__menu-bars::before {
  top: -6px;
}

.top-nav__menu-bars::after {
  top: 6px;
}

.top-nav__user {
  justify-content: center;
  max-width: 180px;
  overflow: hidden;
  color: var(--color-text-strong);
  font-size: 13px;
  font-weight: 900;
  line-height: 1;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* Study pages use the nav as app chrome, aligned to the left rail. */
.top-nav[data-nav-context="study"] {
  background: var(--color-surface-card);
  backdrop-filter: none;
}

.top-nav[data-nav-context="study"] .top-nav__inner {
  display: grid;
  grid-template-columns: var(--sidebar-width) minmax(0, 1fr);
  gap: 0;
  max-width: none;
  min-height: 72px;
  margin: 0;
  padding: 0;
}

.top-nav[data-nav-context="study"] .top-nav__brand {
  align-self: stretch;
  width: 100%;
  padding: 0 var(--space-4);
  background: var(--color-surface-panel);
  border-right: var(--border-width-strong) solid var(--color-border-soft);
}

.top-nav[data-nav-context="study"] .top-nav__links {
  display: none;
}

.top-nav[data-nav-context="study"] .top-nav__actions {
  align-items: center;
  width: min(100%, var(--curriculum-max-width));
  min-width: 0;
  margin: 0 auto;
  padding: 0 var(--space-8);
}

.top-nav[data-nav-context="study"] .top-nav__link,
.top-nav[data-nav-context="study"] .top-nav__user,
.top-nav[data-nav-context="study"] .top-nav__button {
  display: inline-flex;
  align-items: center;
  min-height: calc(var(--space-unit) * 9);
  line-height: 1;
}

.top-nav[data-nav-context="study"] .top-nav__text-button {
  justify-content: center;
}

/* Shared building blocks
   These classes are intentionally reusable so new UI can stay consistent. */
.button {
  border: none;
  cursor: pointer;
  transition:
    transform var(--transition-fast),
    box-shadow var(--transition-fast),
    background var(--transition-base),
    color var(--transition-base),
    border-color var(--transition-base),
    opacity var(--transition-base);
}

.button:disabled {
  cursor: not-allowed;
  opacity: 0.5;
  transform: none;
}

.button--pill {
  border-radius: var(--radius-pill);
  padding: var(--space-2) var(--space-4);
  font-size: 12px;
  font-weight: 800;
}

.button--card {
  border-radius: var(--radius-lg);
  padding: var(--space-2) var(--space-4);
  font-size: 12px;
  font-weight: 800;
}

.button--full {
  width: 100%;
}

.button--accent {
  background: var(--color-primary-600);
  color: var(--color-surface-card);
  box-shadow: var(--shadow-primary);
}

.button--accent:hover {
  transform: translate(-1px, -1px);
  box-shadow: calc(var(--space-1) + 1px) calc(var(--space-1) + 1px) 0 var(--color-primary-800);
}

.button--accent:active {
  transform: translate(3px, 3px);
  box-shadow: 1px 1px 0 var(--color-primary-800);
}

.button--dark {
  background: var(--color-text-strong);
  color: var(--color-surface-card);
  box-shadow: var(--shadow-dark);
}

.button--dark:hover {
  transform: translate(-1px, -1px);
  box-shadow: calc(var(--space-1) + 1px) calc(var(--space-1) + 1px) 0 #0a0018;
}

.button--soft-primary {
  background: var(--color-primary-050);
  color: var(--color-primary-500);
}

.button--soft-primary:hover {
  background: var(--color-border-soft);
}

.button--soft-success {
  background: var(--color-success-050);
  color: var(--color-success-700);
}

.button--soft-success:hover {
  background: var(--color-success-100);
}

.button--soft-info {
  background: var(--color-info-050);
  color: var(--color-info-500);
}

.button--soft-info:hover {
  background: var(--color-info-100);
}

.button--soft-danger {
  background: var(--color-primary-100);
  color: var(--color-primary-700);
}

.button--soft-danger:hover {
  background: var(--color-primary-200);
}

.button--soft-lavender {
  background: var(--color-lavender-050);
  color: var(--color-lavender-500);
}

.button--soft-lavender:hover {
  background: var(--color-lavender-100);
}

.button--outline {
  background: var(--color-surface-card);
  border: var(--border-width-soft) solid var(--color-border-card);
  color: var(--color-text-muted);
}

.button--outline:hover {
  background: var(--color-surface-soft);
}

.button--ghost {
  background: transparent;
  border-color: transparent;
  color: var(--color-text-muted);
}

.button--ghost:hover {
  background: var(--color-surface-soft);
  color: var(--color-text-base);
}

.button--dashed {
  border-style: dashed;
  border-width: var(--border-width-strong);
  border-color: var(--color-primary-300);
  color: var(--color-primary-500);
}

.button--dashed:hover {
  background: var(--color-primary-050);
}

/* ---------- Confirm dialog (guards destructive actions) ---------- */

.confirm-overlay {
  position: fixed;
  inset: 0;
  z-index: 90;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-6);
  background: rgba(30, 10, 60, 0.45);
  animation: confirm-fade 0.18s ease forwards;
}

.confirm-card {
  position: relative;
  max-width: calc(var(--space-unit) * 92);
  width: 100%;
  padding: var(--space-7) var(--space-6) var(--space-6);
  border-radius: var(--radius-3xl);
  background: var(--color-surface-card);
  text-align: center;
  box-shadow: 0 24px 60px rgba(30, 10, 60, 0.3);
  animation: confirm-pop 0.22s cubic-bezier(0.22, 1, 0.36, 1) forwards;
}

.confirm-card__icon {
  font-size: 38px;
  line-height: 1;
}

.confirm-card__title {
  margin-top: var(--space-3);
  font-size: 19px;
  font-weight: 900;
  color: var(--color-text-strong);
}

.confirm-card__body {
  margin-top: var(--space-2);
  font-size: 14px;
  font-weight: 600;
  line-height: 1.5;
  color: var(--color-text-muted);
}

.confirm-card__actions {
  display: flex;
  gap: var(--space-3);
  margin-top: var(--space-6);
}

.confirm-card__actions .button {
  flex: 1;
  border-radius: var(--radius-2xl);
  padding: calc(var(--space-unit) * 3);
  font-size: 14px;
  font-weight: 900;
}

@keyframes confirm-fade {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes confirm-pop {
  0% { opacity: 0; transform: scale(0.92); }
  100% { opacity: 1; transform: scale(1); }
}

@media (prefers-reduced-motion: reduce) {
  .confirm-overlay,
  .confirm-card { animation: confirm-fade 0.18s ease forwards; }
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  border-radius: var(--radius-pill);
  padding: calc(var(--space-unit) * 0.5) calc(var(--space-unit) * 2.25);
  font-size: 10px;
  font-weight: 800;
}

.pill--beginner {
  background: var(--color-success-050);
  color: var(--color-success-700);
}

.pill--intermediate {
  background: var(--color-warning-050);
  color: var(--color-warning-700);
}

.pill--advanced {
  background: var(--color-primary-100);
  color: var(--color-primary-800);
}

.pill--wip {
  background: var(--color-primary-050);
  color: var(--color-primary-500);
}

.badge {
  display: inline-flex;
  align-items: center;
  border-radius: var(--radius-pill);
  padding: calc(var(--space-unit) * 0.75) calc(var(--space-unit) * 2.5);
  font-size: 10px;
  font-weight: 800;
}

.badge--time {
  background: var(--color-lavender-050);
  color: var(--color-text-muted);
}

.badge--done {
  background: var(--color-success-050);
  color: var(--color-success-700);
}

.badge--wip {
  background: var(--color-primary-050);
  color: var(--color-primary-500);
}

.badge--mastery-unset {
  background: transparent;
  color: var(--color-text-muted);
  border: 1px dashed var(--color-border-soft);
  cursor: pointer;
}

.badge--mastery-familiar {
  background: var(--color-lavender-050);
  color: var(--color-lavender-500);
  cursor: pointer;
}

.badge--mastery-practiced {
  background: var(--color-info-050);
  color: var(--color-info-500);
  cursor: pointer;
}

.badge--mastery-mastered {
  background: var(--color-success-050);
  color: var(--color-success-700);
  cursor: pointer;
}

.lc-section-row__mastery-badge {
  font-family: inherit;
  font-size: 10px;
  font-weight: 800;
  border: none;
  padding: calc(var(--space-unit) * 0.75) calc(var(--space-unit) * 2.5);
}

.progress-track {
  width: 100%;
  overflow: hidden;
  border-radius: var(--radius-pill);
  background: var(--color-primary-050);
}

.progress-fill {
  height: 100%;
  border-radius: var(--radius-pill);
  background: var(--color-primary-600);
  transition: width 0.4s ease;
}

.text-muted {
  color: var(--color-text-muted);
}

.screen-reader-only {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}