/**
 * Token-based utility classes (phase 12) — replaces common inline styles.
 */

/* Screen reader only */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Typography */
.u-text-secondary { color: var(--text-secondary); }
.u-text-muted { color: var(--text-muted); }
.u-text-brand { color: var(--brand); }
.u-text-sm { font-size: 13px; font-weight: 600; }
.u-text-xs { font-size: 12px; font-weight: 600; }
.u-text-caption {
  font-size: 11px;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.u-text-body { font-size: 13px; font-weight: 400; color: var(--text-secondary); line-height: 1.6; }
.u-text-lede { font-size: 12px; font-weight: 600; color: var(--text-secondary); line-height: 1.55; }

/* Spacing */
.u-m-0 { margin: 0; }
.u-mb-sm { margin-bottom: 12px; }
.u-mb-md { margin-bottom: 16px; }
.u-mt-sm { margin-top: 8px; }
.u-mt-md { margin-top: 10px; }

/* Layout */
.u-flex-actions {
  display: flex;
  gap: 9px;
  flex-wrap: wrap;
  margin-top: 22px;
}
.u-flex-actions-sm {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 18px;
}
.u-icon-hero { font-size: 32px; margin-bottom: 10px; }

/* Lists */
.u-list-secondary {
  font-size: 12px;
  color: var(--text-secondary);
  line-height: 1.7;
  padding-left: 18px;
  margin: 8px 0;
}
.u-list-compact {
  font-size: 12px;
  color: var(--text-secondary);
  padding-left: 18px;
  margin: 4px 0 10px;
}

/* Exam responsive — long content scroll */
html.exam-scroll-active {
  overflow-y: scroll;
  scrollbar-gutter: stable;
}
html.exam-scroll-active::-webkit-scrollbar {
  width: 10px;
}
html.exam-scroll-active::-webkit-scrollbar-track {
  background: var(--bg2);
}
html.exam-scroll-active::-webkit-scrollbar-thumb {
  background: var(--border2);
  border-radius: 5px;
}
html.exam-scroll-active::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}
.exam-scroll-top {
  position: fixed;
  right: 20px;
  bottom: 88px;
  z-index: 100;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 1px solid var(--border2);
  background: var(--surface);
  color: var(--text);
  font-size: 20px;
  font-weight: 700;
  line-height: 1;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(15, 23, 42, 0.15);
  opacity: 0;
  pointer-events: none;
  transform: translateY(8px);
  transition: opacity 0.2s, transform 0.2s;
}
.exam-scroll-top.visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}
.exam-scroll-top:hover {
  background: var(--surface2);
}
#examScreen {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}
#examScreen .module-wrap,
#examScreen .question-block {
  max-width: 100%;
}
@media (max-width: 639px) {
  #examScreen .exam-topbar {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-2);
  }
  #examScreen .exam-actions {
    width: 100%;
    flex-wrap: wrap;
  }
  #examScreen .opt,
  #examScreen .rf-btn {
    min-height: 44px;
  }
  #flashcardScreen .fc-card {
    min-height: 140px;
  }
}

.u-auth-lede { font-size: 13px; color: var(--text-secondary); margin-bottom: 12px; line-height: 1.5; }
.u-auth-legal {
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 10px;
  line-height: 1.5;
  text-align: center;
}
.u-auth-link { color: var(--brand); font-size: 12px; }
.u-warning-sm { font-size: 12px; color: var(--orange); margin-bottom: 12px; }
.u-section-label {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin: 18px 0 10px;
}
.u-site-footer {
  text-align: center;
  padding: 20px 16px 28px;
  font-size: 11px;
  color: var(--text-muted);
  line-height: 1.8;
}
.u-site-footer a { color: var(--text-secondary); text-decoration: none; margin: 0 8px; }
.u-site-footer a.link-brand { color: var(--brand); font-weight: 600; }
.u-site-footer-btn {
  background: none; border: none; cursor: pointer; font-family: inherit;
  font-size: inherit; font-weight: inherit; color: var(--text-secondary);
  margin: 0 8px; padding: 0; text-decoration: underline;
}
.u-site-footer-btn:hover { color: var(--brand); }
.u-profile-row { display: flex; align-items: center; gap: 10px; }
.u-flex-inline { display: flex; gap: 9px; flex-wrap: wrap; align-items: center; }
.u-fc-level-label {
  font-size: 11px;
  color: var(--text-muted);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

:focus-visible {
  outline: 2px solid var(--brand);
  outline-offset: 2px;
}
.btn-sm:focus-visible,
.opt:focus-within,
.fc-card:focus-visible {
  outline: 2px solid var(--brand);
  outline-offset: 2px;
}