/*
 * Sukud design system - learning
 * Roadmap, class sessions, attendance, materials, tips and carousel,
 * week strip, quizzes (cards, builder, grading, countdown) and the
 * reorderable list.
 */

/* ======================================================================
 * Roadmap: a winding path of round stops, one column per chapter
 * ====================================================================== */
.sk-roadmap { --step: 54px; display: flex; flex-direction: column; gap: 28px; margin: 0; padding: 0; list-style: none; }
@container (max-width: 420px) { .sk-roadmap { --step: 34px; } }
@media (max-width: 420px) { .sk-roadmap { --step: 34px; } }
.sk-roadmap__chapter { display: flex; flex-direction: column; align-items: center; gap: 22px; }
.sk-roadmap__banner {
  position: relative;
  display: flex; flex-direction: column; gap: 2px;
  width: 100%;
  padding: 14px 18px;
  border-radius: 20px;
  background: linear-gradient(135deg, var(--sk-brand-9), var(--sk-violet-9));
  color: #fff;
  box-shadow: 0 6px 0 -1px rgb(var(--sk-brand-rgb) / 0.35), var(--sk-shadow-sm);
}
.sk-roadmap__banner .sk-eyebrow { color: rgb(255 255 255 / 0.78); }
.sk-roadmap__banner.is-locked { background: var(--sk-surface-sunken); color: var(--sk-fg-muted); box-shadow: none; }
.sk-roadmap__banner.is-locked .sk-eyebrow { color: var(--sk-fg-subtle); }
.sk-roadmap__banner.is-done { background: linear-gradient(135deg, var(--sk-green-9), var(--sk-teal-9)); box-shadow: 0 6px 0 -1px rgb(var(--sk-green-rgb) / 0.35), var(--sk-shadow-sm); }
[data-theme="dark"] .sk-roadmap__banner:not(.is-locked):not(.is-done) { background: linear-gradient(135deg, color-mix(in oklab, var(--sk-brand-9) 46%, var(--sk-surface)), color-mix(in oklab, var(--sk-violet-9) 34%, var(--sk-surface))); box-shadow: inset 0 0 0 1px rgb(var(--sk-brand-rgb) / 0.24), 0 6px 0 -1px rgb(var(--sk-brand-rgb) / 0.18); }
[data-theme="dark"] .sk-roadmap__banner.is-done { background: linear-gradient(135deg, color-mix(in oklab, var(--sk-green-9) 44%, var(--sk-surface)), color-mix(in oklab, var(--sk-teal-9) 32%, var(--sk-surface))); box-shadow: inset 0 0 0 1px rgb(var(--sk-green-rgb) / 0.24), 0 6px 0 -1px rgb(var(--sk-green-rgb) / 0.18); }
.sk-roadmap__title { font-family: var(--sk-font-display); font-size: var(--sk-text-lg); font-weight: var(--sk-weight-bold); letter-spacing: -0.015em; }
.sk-roadmap__desc { font-size: var(--sk-text-sm); opacity: 0.85; }
.sk-roadmap__count {
  position: absolute; top: 14px; right: 14px;
  padding: 3px 10px;
  border-radius: var(--sk-radius-full);
  background: rgb(255 255 255 / 0.18);
  font-size: var(--sk-text-xs); font-weight: var(--sk-weight-semibold);
  font-variant-numeric: tabular-nums;
}
.sk-roadmap__banner.is-locked .sk-roadmap__count { background: var(--sk-surface); }

.sk-roadmap__stops { display: flex; flex-direction: column; align-items: center; gap: 18px; margin: 0; padding: 0; list-style: none; }
.sk-roadmap__stop {
  position: relative;
  display: flex; flex-direction: column; align-items: center; gap: 6px;
  transform: translateX(calc(var(--sway, 0) * var(--step)));
  animation: sk-rise var(--sk-dur-slower) var(--sk-ease-out) both;
}
.sk-roadmap__node {
  --shade: var(--sk-brand-11);
  position: relative;
  display: grid; place-items: center;
  width: 64px; height: 64px;
  border-radius: 50%;
  background: var(--sk-surface);
  color: var(--sk-brand-11);
  border: 2px solid var(--sk-brand-6);
  box-shadow: 0 5px 0 var(--sk-brand-6);
  text-decoration: none;
  transition: transform var(--sk-dur-base) var(--sk-ease-spring), box-shadow var(--sk-dur-fast);
}
a.sk-roadmap__node:hover { transform: translateY(-2px); box-shadow: 0 7px 0 var(--sk-brand-6); }
a.sk-roadmap__node:active { transform: translateY(4px); box-shadow: 0 1px 0 var(--sk-brand-6); }
.sk-roadmap__stop.is-done .sk-roadmap__node { background: var(--sk-green-9); border-color: var(--sk-green-9); color: #fff; box-shadow: 0 5px 0 var(--sk-green-11); }
.sk-roadmap__stop.is-done a.sk-roadmap__node:hover { box-shadow: 0 7px 0 var(--sk-green-11); }
.sk-roadmap__stop.is-done a.sk-roadmap__node:active { box-shadow: 0 1px 0 var(--sk-green-11); }
.sk-roadmap__stop.is-current .sk-roadmap__node { width: 74px; height: 74px; background: var(--sk-brand-9); border-color: var(--sk-brand-9); color: #fff; box-shadow: 0 6px 0 var(--sk-brand-11); }
.sk-roadmap__stop.is-current .sk-roadmap__node::after {
  content: '';
  position: absolute; inset: -8px;
  border-radius: 50%;
  border: 3px solid rgb(var(--sk-brand-rgb) / 0.35);
  animation: sk-pulse-ring 2.2s var(--sk-ease-out) infinite;
}
.sk-roadmap__stop.is-current .sk-roadmap__node .sk-icon { margin-left: 3px; }
.sk-roadmap__stop.is-missed .sk-roadmap__node { background: var(--sk-amber-3); border-color: var(--sk-amber-8); color: var(--sk-amber-11); box-shadow: 0 5px 0 var(--sk-amber-8); }
.sk-roadmap__stop.is-missed .sk-roadmap__label small { color: var(--sk-amber-11); }
.sk-roadmap__stop.is-locked .sk-roadmap__node { background: var(--sk-surface-sunken); border-color: var(--sk-border); color: var(--sk-fg-subtle); box-shadow: 0 5px 0 var(--sk-border); }
.sk-roadmap__label { display: flex; flex-direction: column; align-items: center; max-width: 18ch; text-align: center; line-height: 1.25; }
.sk-roadmap__label b { font-size: var(--sk-text-sm); font-weight: var(--sk-weight-semibold); }
.sk-roadmap__label small { font-size: var(--sk-text-xs); color: var(--sk-fg-subtle); }
.sk-roadmap__stop.is-locked .sk-roadmap__label b { color: var(--sk-fg-muted); }
.sk-roadmap__start {
  position: absolute; bottom: calc(100% + 6px); left: 50%;
  padding: 5px 12px;
  border-radius: var(--sk-radius-full);
  background: var(--sk-surface-raised);
  border: 1px solid var(--sk-brand-6);
  color: var(--sk-brand-11);
  font-size: var(--sk-text-xs); font-weight: var(--sk-weight-bold);
  letter-spacing: 0.04em; text-transform: uppercase;
  white-space: nowrap;
  box-shadow: var(--sk-shadow-sm);
  transform: translateX(-50%);
  animation: sk-roadmap-bob 2.4s var(--sk-ease-in-out) infinite;
  pointer-events: none;
}
.sk-roadmap__start::after { content: ''; position: absolute; top: 100%; left: 50%; width: 8px; height: 8px; margin: -4px 0 0 -4px; background: inherit; border: inherit; border-width: 0 1px 1px 0; transform: rotate(45deg); }
@keyframes sk-roadmap-bob { 0%, 100% { transform: translate(-50%, 0); } 50% { transform: translate(-50%, -4px); } }
.sk-roadmap__stop.is-current { margin-top: 26px; }

/* ======================================================================
 * Class session header and attendance
 * ====================================================================== */
.sk-session { display: flex; flex-direction: column; gap: 16px; min-width: 0; }
.sk-session__top { display: flex; align-items: flex-start; gap: 14px; flex-wrap: wrap; }
.sk-session__titles { flex: 1 1 260px; min-width: 0; display: flex; flex-direction: column; gap: 6px; }
.sk-session__title { font-family: var(--sk-font-display); font-size: var(--sk-display-sm); font-weight: var(--sk-weight-bold); letter-spacing: var(--sk-tracking-display); line-height: 1.15; text-wrap: balance; }
.sk-session__actions { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.sk-session__stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(118px, 1fr)); gap: 8px; margin: 0; }
.sk-session__stats > div { display: flex; flex-direction: column-reverse; gap: 1px; padding: 10px 14px; border-radius: 14px; background: var(--sk-surface-sunken); }
.sk-session__stats dt { font-size: var(--sk-text-xs); color: var(--sk-fg-muted); }
.sk-session__stats dd { margin: 0; font-family: var(--sk-font-display); font-size: var(--sk-text-xl); font-weight: var(--sk-weight-bold); letter-spacing: -0.02em; font-variant-numeric: tabular-nums; }
@media (max-width: 639px) { .sk-session__actions { width: 100%; } .sk-session__actions > .sk-btn { flex: 1 1 0; } }

.sk-attend { display: flex; align-items: center; gap: 10px; min-width: 0; }
.sk-attend__avatar { position: relative; flex-shrink: 0; display: inline-flex; }
.sk-attend__mark {
  position: absolute; right: -3px; bottom: -3px;
  display: grid; place-items: center;
  width: 16px; height: 16px;
  border-radius: 50%;
  background: var(--t-solid); color: var(--t-on);
  box-shadow: 0 0 0 2px var(--sk-surface);
}
.sk-attend__mark .sk-icon { stroke-width: 3; }
.sk-attend__text { display: flex; flex-direction: column; min-width: 0; line-height: 1.25; }
.sk-attend__name { font-size: var(--sk-text-sm); font-weight: var(--sk-weight-semibold); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.sk-attend__status { font-size: var(--sk-text-xs); color: var(--t-text); font-weight: var(--sk-weight-medium); }

/* ======================================================================
 * Materials
 * ====================================================================== */
.sk-material {
  position: relative;
  display: flex; flex-direction: column;
  min-width: 0; width: 100%;
  padding: 6px;
  border: 1px solid var(--sk-border-subtle);
  border-radius: 18px;
  background: var(--sk-surface);
  color: var(--sk-fg);
  text-align: start;
  text-decoration: none;
  box-shadow: var(--sk-shadow-xs);
  cursor: pointer;
  transition: transform var(--sk-dur-base) var(--sk-ease-spring), box-shadow var(--sk-dur-base), border-color var(--sk-dur-fast);
}
.sk-material-wrap { position: relative; min-width: 0; }
.sk-material__download { position: absolute; top: 12px; right: 12px; z-index: 2; background: var(--sk-surface) !important; box-shadow: var(--sk-shadow-sm); }
.sk-material:hover { transform: translateY(-2px); box-shadow: var(--sk-shadow-md); border-color: var(--t-border); }
.sk-material:active { transform: scale(0.98); }
.sk-material__preview {
  position: relative;
  display: grid; place-items: center;
  aspect-ratio: 4 / 3;
  border-radius: 13px;
  background: radial-gradient(120% 90% at 20% 10%, var(--t-soft), var(--t-subtle));
  overflow: hidden;
}
.sk-material__preview img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; transition: transform var(--sk-dur-slower) var(--sk-ease-out); }
.sk-material:hover .sk-material__preview img { transform: scale(1.04); }
.sk-material__glyph { display: grid; place-items: center; width: 54px; height: 54px; border-radius: 50%; background: var(--sk-surface); color: var(--t-text); box-shadow: var(--sk-shadow-sm); transition: transform var(--sk-dur-base) var(--sk-ease-spring); }
.sk-material:hover .sk-material__glyph { transform: rotate(-6deg) scale(1.06); }
.sk-material__kind {
  position: absolute; top: 8px; left: 8px;
  padding: 2px 8px;
  border-radius: var(--sk-radius-full);
  background: color-mix(in oklab, var(--t-solid) 82%, #000); color: #fff;
  font-size: 10px; font-weight: var(--sk-weight-bold); letter-spacing: 0.06em;
}
.sk-material__play {
  position: absolute;
  display: grid; place-items: center;
  width: 42px; height: 42px;
  border-radius: 50%;
  background: rgb(0 0 0 / 0.55); color: #fff;
  backdrop-filter: blur(6px);
  transition: transform var(--sk-dur-base) var(--sk-ease-spring);
}
.sk-material__play .sk-icon { margin-left: 2px; fill: currentColor; }
.sk-material:hover .sk-material__play { transform: scale(1.12); }
.sk-material__preview:has(.sk-material__play) .sk-material__glyph { display: none; }
.sk-material__info { display: flex; flex-direction: column; gap: 1px; padding: 9px 6px 4px; min-width: 0; }
.sk-material__name { font-size: var(--sk-text-sm); font-weight: var(--sk-weight-semibold); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.sk-material__meta { font-size: var(--sk-text-xs); color: var(--sk-fg-subtle); }
.sk-materials { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 12px; }

.sk-material-chip {
  display: inline-flex; align-items: center; gap: 6px;
  max-width: 100%;
  height: 28px;
  padding: 0 11px 0 9px;
  border-radius: var(--sk-radius-full);
  background: var(--t-soft); color: var(--t-text);
  font-size: var(--sk-text-xs); font-weight: var(--sk-weight-semibold);
  text-decoration: none;
  vertical-align: middle;
  transition: background-color var(--sk-dur-fast), transform var(--sk-dur-base) var(--sk-ease-spring);
}
.sk-material-chip span { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.sk-material-chip .sk-icon { flex-shrink: 0; }
.sk-material-chip:hover { background: var(--t-soft-hover); transform: translateY(-1px); }

/* ======================================================================
 * Tips and carousel
 * ====================================================================== */
.sk-tip {
  position: relative;
  display: flex; flex-direction: column; gap: 6px;
  height: 100%;
  padding: 16px 18px 18px;
  border-radius: 20px;
  background: linear-gradient(160deg, var(--t-soft), var(--t-subtle) 70%);
  color: var(--sk-fg);
  overflow: hidden;
  isolation: isolate;
}
.sk-tip::after { content: ''; position: absolute; right: -44px; bottom: -44px; z-index: -1; width: 128px; height: 128px; border-radius: 50%; background: rgb(var(--t-rgb) / 0.1); }
.sk-tip__head { display: flex; align-items: center; gap: 8px; color: var(--t-text); margin-bottom: 2px; }
.sk-tip__head > .sk-icon { width: 18px; height: 18px; }
.sk-tip__category { padding: 2px 9px; border-radius: var(--sk-radius-full); background: var(--sk-surface); font-size: var(--sk-text-2xs); font-weight: var(--sk-weight-bold); letter-spacing: var(--sk-tracking-caps); text-transform: uppercase; }
.sk-tip__date { margin-inline-start: auto; font-size: var(--sk-text-xs); color: var(--sk-fg-subtle); }
.sk-tip__title { font-family: var(--sk-font-display); font-size: var(--sk-text-lg); font-weight: var(--sk-weight-bold); letter-spacing: -0.015em; line-height: 1.25; text-wrap: balance; }
.sk-tip__text { font-size: var(--sk-text-sm); color: var(--sk-fg-muted); line-height: 1.55; }
.sk-tip__actions { display: flex; flex-wrap: wrap; gap: 6px; margin-top: auto; padding-top: 10px; }
.sk-tip__actions form { display: contents; }
.sk-tip__author { display: inline-flex; align-items: center; gap: 7px; margin-top: auto; padding-top: 8px; font-size: var(--sk-text-xs); font-weight: var(--sk-weight-medium); color: var(--sk-fg-muted); }

.sk-carousel { display: flex; flex-direction: column; gap: 12px; min-width: 0; }
.sk-carousel__track {
  display: flex; gap: 12px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scroll-behavior: smooth;
  scrollbar-width: none;
  overscroll-behavior-x: contain;
  padding: 2px;
  margin: -2px;
}
.sk-carousel__track::-webkit-scrollbar { display: none; }
.sk-carousel__track:focus-visible { outline: none; box-shadow: var(--sk-focus-ring); border-radius: 20px; }
.sk-carousel__slide { flex: 0 0 min(320px, 86%); scroll-snap-align: start; }
.sk-carousel__nav { display: flex; align-items: center; justify-content: center; gap: 12px; }
.sk-carousel__dots { display: flex; align-items: center; gap: 6px; }
.sk-carousel__dot {
  width: 8px; height: 8px;
  padding: 0;
  border: 0;
  border-radius: var(--sk-radius-full);
  background: var(--sk-border-strong);
  cursor: pointer;
  transition: width var(--sk-dur-slow) var(--sk-ease-spring), background-color var(--sk-dur-base);
}
.sk-carousel__dot.is-active { width: 22px; background: var(--sk-brand-9); }
@media (pointer: coarse) { .sk-carousel__dot { position: relative; } .sk-carousel__dot::after { content: ''; position: absolute; inset: -10px -4px; } }

/* ======================================================================
 * Week strip
 * ====================================================================== */
.sk-week { display: grid; grid-template-columns: repeat(7, minmax(0, 1fr)); gap: 6px; max-width: 560px; }
.sk-week__day {
  display: flex; flex-direction: column; align-items: center; gap: 2px;
  padding: 8px 0 7px;
  border-radius: 18px;
  color: var(--sk-fg);
  text-decoration: none;
  transition: background-color var(--sk-dur-fast), transform var(--sk-dur-base) var(--sk-ease-spring), color var(--sk-dur-fast);
}
a.sk-week__day:hover { background: var(--sk-surface-hover); }
a.sk-week__day:active { transform: scale(0.94); }
.sk-week__label { font-size: var(--sk-text-2xs); font-weight: var(--sk-weight-semibold); letter-spacing: 0.04em; text-transform: uppercase; color: var(--sk-fg-subtle); }
.sk-week__num { display: grid; place-items: center; width: 34px; height: 34px; border-radius: 50%; font-family: var(--sk-font-display); font-size: var(--sk-text-lg); font-weight: var(--sk-weight-bold); font-variant-numeric: tabular-nums; }
.sk-week__dots { display: flex; gap: 3px; height: 5px; }
.sk-week__dots i { width: 5px; height: 5px; border-radius: 50%; background: var(--t-solid); }
.sk-week__day.is-today .sk-week__num { box-shadow: inset 0 0 0 2px var(--sk-brand-7); color: var(--sk-brand-11); }
.sk-week__day.is-selected { background: var(--sk-brand-9); color: #fff; box-shadow: 0 6px 16px -6px rgb(var(--sk-brand-rgb) / 0.7); }
.sk-week__day.is-selected .sk-week__label { color: #fff; }
.sk-week__day.is-selected .sk-week__num { box-shadow: none; color: #fff; }
.sk-week__day.is-selected .sk-week__dots i { background: #fff; }
a.sk-week__day.is-selected:hover { background: var(--sk-brand-10); }

/* ======================================================================
 * Quiz card
 * ====================================================================== */
.sk-quiz-card {
  position: relative;
  display: flex; flex-direction: column; gap: 6px;
  min-width: 0;
  padding: 14px 16px 16px;
  border: 1px solid var(--sk-border-subtle);
  border-radius: var(--sk-radius-card);
  background: var(--sk-surface);
  box-shadow: var(--sk-shadow-sm);
  transition: transform var(--sk-dur-base) var(--sk-ease-spring), box-shadow var(--sk-dur-base), border-color var(--sk-dur-fast);
}
[data-theme="dark"] .sk-quiz-card { border-color: var(--sk-border); }
.sk-quiz-card:hover { transform: translateY(-2px); box-shadow: var(--sk-shadow-md); border-color: var(--sk-brand-6); }
.sk-quiz-card__link { position: absolute; inset: 0; z-index: 0; border-radius: inherit; }
.sk-quiz-card__link:focus-visible { outline: none; box-shadow: var(--sk-focus-ring); }
.sk-quiz-card__top { display: flex; align-items: center; gap: 8px; margin-bottom: 4px; }
.sk-quiz-card__icon { display: grid; place-items: center; width: 36px; height: 36px; border-radius: 50%; background: var(--sk-brand-3); color: var(--sk-brand-11); transition: transform var(--sk-dur-base) var(--sk-ease-spring); }
.sk-quiz-card:hover .sk-quiz-card__icon { transform: rotate(-8deg) scale(1.06); }
.sk-quiz-card[style*="--subject-rgb"] .sk-quiz-card__icon { background: rgb(var(--subject-rgb) / 0.14); color: rgb(var(--subject-rgb)); }
.sk-quiz-card__menu { position: relative; z-index: 1; margin-inline-start: auto; }
.sk-quiz-card__title { font-family: var(--sk-font-display); font-size: var(--sk-text-lg); font-weight: var(--sk-weight-bold); letter-spacing: -0.015em; line-height: 1.25; }
.sk-quiz-card__subject { font-size: var(--sk-text-sm); color: var(--sk-fg-muted); margin-top: -4px; }
.sk-quiz-card__facts { display: flex; flex-wrap: wrap; gap: 4px 14px; margin: 4px 0 6px; font-size: var(--sk-text-xs); color: var(--sk-fg-muted); }
.sk-quiz-card__facts > span { display: inline-flex; align-items: center; gap: 5px; }
.sk-quiz-card__facts .sk-icon { color: var(--sk-fg-subtle); }

/* ======================================================================
 * Question editor and grading
 * ====================================================================== */
.sk-qedit {
  display: flex; flex-direction: column;
  min-width: 0;
  border: 1px solid var(--sk-border-subtle);
  border-radius: var(--sk-radius-card);
  background: var(--sk-surface);
  box-shadow: var(--sk-shadow-sm);
  transition: box-shadow var(--sk-dur-base), transform var(--sk-dur-base) var(--sk-ease-spring), border-color var(--sk-dur-fast);
}
[data-theme="dark"] .sk-qedit { border-color: var(--sk-border); }
.sk-qedit__head { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; padding: 10px 10px 10px 8px; }
.sk-qedit__handle, .sk-sortable__handle {
  display: grid; place-items: center;
  width: 28px; height: 32px;
  border-radius: 10px;
  color: var(--sk-fg-subtle);
  cursor: grab;
  touch-action: none;
  transition: background-color var(--sk-dur-fast), color var(--sk-dur-fast);
}
.sk-qedit__handle:hover, .sk-sortable__handle:hover { background: var(--sk-surface-hover); color: var(--sk-fg); }
.sk-qedit__handle:focus-visible, .sk-sortable__handle:focus-visible { outline: none; box-shadow: var(--sk-focus-ring); }
.sk-qedit__num {
  display: inline-grid; place-items: center;
  min-width: 34px; height: 26px;
  padding: 0 8px;
  border-radius: var(--sk-radius-full);
  background: var(--sk-ink-12, var(--sk-fg)); color: var(--sk-fg-inverse);
  font-size: var(--sk-text-xs); font-weight: var(--sk-weight-bold);
  font-variant-numeric: tabular-nums;
}
.sk-qedit__toggle .sk-icon { transition: transform var(--sk-dur-slow) var(--sk-ease-spring); }
.sk-qedit__toggle.is-closed .sk-icon { transform: rotate(-90deg); }
.sk-qedit__body { display: flex; flex-direction: column; gap: 14px; padding: 4px 16px 16px; }
.sk-qedit__options { display: flex; flex-direction: column; gap: 8px; margin: 0; padding: 0; border: 0; min-width: 0; }
.sk-qedit__options > legend { padding: 0; margin-bottom: 8px; }
.sk-qedit__option {
  position: relative;
  display: flex; align-items: center; gap: 10px;
  min-height: var(--sk-control-lg);
  padding: 4px 10px 4px 5px;
  border: 1px solid var(--sk-border);
  border-radius: var(--sk-radius-full);
  background: var(--sk-surface);
  transition: border-color var(--sk-dur-fast), background-color var(--sk-dur-fast), box-shadow var(--sk-dur-fast);
}
.sk-qedit__option > input[type="radio"] { position: absolute; opacity: 0; width: 1px; height: 1px; pointer-events: none; }
.sk-qedit__key {
  display: grid; place-items: center; flex-shrink: 0;
  width: 32px; height: 32px;
  border-radius: 50%;
  background: var(--sk-surface-sunken);
  color: var(--sk-fg-muted);
  font-size: var(--sk-text-sm); font-weight: var(--sk-weight-bold);
  cursor: pointer;
  transition: background-color var(--sk-dur-base), color var(--sk-dur-base), transform var(--sk-dur-base) var(--sk-ease-spring);
}
.sk-qedit__key:hover { background: var(--sk-green-3); color: var(--sk-green-11); }
.sk-qedit__option-input { flex: 1 1 auto; min-width: 0; height: 34px; padding: 0 4px; border: 0; background: transparent; color: var(--sk-fg); font: inherit; font-size: var(--sk-text-md); outline: none; }
.sk-qedit__option-input::placeholder { color: var(--sk-fg-subtle); }
.sk-qedit__correct { display: none; align-items: center; gap: 4px; flex-shrink: 0; padding: 3px 9px; border-radius: var(--sk-radius-full); background: var(--sk-green-9); color: #fff; font-size: var(--sk-text-2xs); font-weight: var(--sk-weight-bold); letter-spacing: 0.03em; }
.sk-qedit__correct .sk-icon { stroke-width: 3; }
.sk-qedit__option:has(input[type="radio"]:checked) { border-color: var(--sk-green-8); background: var(--sk-green-2); }
.sk-qedit__option:has(input[type="radio"]:checked) .sk-qedit__key { background: var(--sk-green-9); color: #fff; transform: scale(1.06); }
.sk-qedit__option:has(input[type="radio"]:checked) .sk-qedit__correct { display: inline-flex; animation: sk-pop var(--sk-dur-slow) var(--sk-ease-spring); }
.sk-qedit__option:has(input[type="radio"]:focus-visible) .sk-qedit__key { box-shadow: var(--sk-focus-ring); }
@media (max-width: 479px) { .sk-qedit__correct { padding: 4px; font-size: 0; gap: 0; } }

.sk-grade {
  display: flex; flex-direction: column; gap: 12px;
  min-width: 0;
  padding: 14px 16px;
  border: 1px solid var(--sk-border-subtle);
  border-radius: var(--sk-radius-card);
  background: var(--sk-surface);
  box-shadow: var(--sk-shadow-sm);
  container-type: inline-size;
  transition: border-color var(--sk-dur-base), background-color var(--sk-dur-base);
}
[data-theme="dark"] .sk-grade { border-color: var(--sk-border); }
.sk-grade.is-correct { border-color: var(--sk-green-6); }
.sk-grade.is-partial { border-color: var(--sk-amber-6); }
.sk-grade.is-wrong { border-color: var(--sk-red-6); }
.sk-grade__head { display: flex; align-items: flex-start; gap: 10px; }
.sk-grade__prompt { flex: 1; min-width: 0; padding-top: 3px; font-weight: var(--sk-weight-semibold); line-height: 1.4; }
.sk-grade__answers { display: grid; gap: 8px; }
@container (min-width: 560px) { .sk-grade__answers { grid-template-columns: 1fr 1fr; } }
.sk-grade__answer { display: flex; flex-direction: column; gap: 4px; padding: 10px 12px; border-radius: 14px; background: var(--sk-surface-sunken); }
.sk-grade__answer p { font-size: var(--sk-text-sm); line-height: 1.55; white-space: pre-wrap; overflow-wrap: anywhere; }
.sk-grade__answer.is-expected { background: var(--sk-teal-2); }
.sk-grade__answer.is-expected .sk-eyebrow { color: var(--sk-teal-11); }
.sk-grade__foot { display: flex; align-items: center; justify-content: space-between; gap: 10px; flex-wrap: wrap; }
.sk-grade__status { flex-shrink: 0; }
.sk-grade__form { display: flex; flex-direction: column; gap: 10px; }
.sk-grade__quick { display: inline-flex; gap: 6px; flex-wrap: wrap; }
.sk-grade__feedback { display: flex; gap: 8px; align-items: flex-start; margin: 0; padding: 8px 10px; border-radius: 10px; background: var(--sk-surface-sunken); font-size: var(--sk-text-sm); }
.sk-grade__feedback > .sk-icon { margin-top: 3px; flex-shrink: 0; color: var(--sk-fg-muted); }

/* ======================================================================
 * Countdown
 * ====================================================================== */
.sk-countdown {
  --arc: var(--sk-brand-9);
  display: inline-flex; align-items: center; gap: 10px;
  padding: 4px 14px 4px 4px;
  border-radius: var(--sk-radius-full);
  background: var(--sk-surface);
  border: 1px solid var(--sk-border);
  box-shadow: var(--sk-shadow-xs);
  transition: border-color var(--sk-dur-slow), background-color var(--sk-dur-slow);
}
.sk-countdown svg { width: 40px; height: 40px; transform: rotate(-90deg); flex-shrink: 0; }
.sk-countdown circle { fill: none; stroke-width: 4; }
.sk-countdown__track { stroke: var(--sk-surface-sunken); }
.sk-countdown__arc { stroke: var(--arc); stroke-linecap: round; stroke-dasharray: 100; transition: stroke-dashoffset 1s linear, stroke var(--sk-dur-slow); }
.sk-countdown__text { display: flex; flex-direction: column; line-height: 1.1; }
.sk-countdown__text b { font-family: var(--sk-font-display); font-size: var(--sk-text-lg); font-weight: var(--sk-weight-bold); font-variant-numeric: tabular-nums; letter-spacing: -0.01em; }
.sk-countdown__text small { font-size: var(--sk-text-2xs); color: var(--sk-fg-subtle); text-transform: uppercase; letter-spacing: var(--sk-tracking-caps); font-weight: var(--sk-weight-semibold); }
.sk-countdown.is-low { --arc: var(--sk-amber-9); border-color: var(--sk-amber-6); }
.sk-countdown.is-low .sk-countdown__text b { color: var(--sk-amber-11); }
.sk-countdown.is-critical { --arc: var(--sk-red-9); border-color: var(--sk-red-7); background: var(--sk-red-2); }
.sk-countdown.is-critical .sk-countdown__text b { color: var(--sk-red-11); animation: sk-pulse 1s var(--sk-ease-in-out) infinite; }

/* ======================================================================
 * Reorderable list
 * ====================================================================== */
.sk-sortable { display: flex; flex-direction: column; gap: 8px; margin: 0; padding: 0; list-style: none; }
.sk-sortable__item {
  position: relative;
  display: flex; align-items: center; gap: 10px;
  min-height: 56px;
  padding: 8px 10px 8px 6px;
  border: 1px solid var(--sk-border-subtle);
  border-radius: 16px;
  background: var(--sk-surface);
  box-shadow: var(--sk-shadow-xs);
  transition: box-shadow var(--sk-dur-base), border-color var(--sk-dur-fast), background-color var(--sk-dur-fast);
}
[data-theme="dark"] .sk-sortable__item { border-color: var(--sk-border); }
.sk-sortable__text { flex: 1 1 auto; min-width: 0; display: flex; flex-direction: column; line-height: 1.3; }
.sk-sortable__title { font-size: var(--sk-text-sm); font-weight: var(--sk-weight-semibold); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.sk-sortable__meta { font-size: var(--sk-text-xs); color: var(--sk-fg-subtle); }
.sk-sortable__actions { display: flex; align-items: center; gap: 2px; }

/* ======================================================================
 * A marked (or being-marked) answer: result and review pages
 * ====================================================================== */
.sk-review-q { display: flex; flex-direction: column; gap: 14px; padding: 16px 18px 18px; border-radius: 20px; background: var(--sk-surface); border: 1px solid var(--sk-border-subtle); box-shadow: var(--sk-shadow-xs); }
.sk-review-q__head { display: flex; align-items: flex-start; gap: 12px; }
.sk-review-q__num { display: grid; place-items: center; flex-shrink: 0; width: 30px; height: 30px; border-radius: 50%; background: var(--t-soft); color: var(--t-text); font-size: var(--sk-text-sm); font-weight: var(--sk-weight-bold); font-variant-numeric: tabular-nums; }
.sk-review-q__title { flex: 1 1 auto; min-width: 0; padding-top: 4px; font-size: var(--sk-text-md); font-weight: var(--sk-weight-semibold); line-height: 1.4; overflow-wrap: anywhere; }
.sk-review-q__answer { display: flex; flex-direction: column; gap: 4px; padding: 12px 14px; border-radius: 14px; background: var(--sk-surface-sunken); }
.sk-review-q__answer p { font-size: var(--sk-text-sm); line-height: 1.6; white-space: pre-line; overflow-wrap: anywhere; }
.sk-review-q__why { display: flex; gap: 8px; align-items: flex-start; padding: 10px 12px; border-radius: 12px; background: var(--sk-amber-2); color: var(--sk-fg-muted); font-size: var(--sk-text-sm); line-height: 1.5; }
.sk-review-q__why .sk-icon { flex-shrink: 0; margin-top: 2px; color: var(--sk-amber-11); }
.sk-review-q .sk-answer { padding-block: 10px; }

/* Quiz result / submitted summary */
.sk-result { display: flex; align-items: center; gap: 24px; padding: 22px; border-radius: 24px; background: linear-gradient(135deg, var(--t-subtle), var(--sk-surface) 70%); border: 1px solid var(--sk-border-subtle); box-shadow: var(--sk-shadow-sm); }
.sk-result__art { flex-shrink: 0; width: 136px; }
.sk-result__text { flex: 1 1 auto; min-width: 0; display: flex; flex-direction: column; gap: 6px; }
.sk-result__title { font-family: var(--sk-font-display); font-size: clamp(1.45rem, 1.1rem + 1.2vw, 2rem); font-weight: var(--sk-weight-black); letter-spacing: -0.03em; line-height: 1.1; text-wrap: balance; }
.sk-result__sub { color: var(--sk-fg-muted); line-height: 1.55; text-wrap: pretty; margin-bottom: 8px; }
@media (max-width: 560px) { .sk-result { flex-direction: column; text-align: center; } .sk-result .sk-cluster { justify-content: center; } }

/* ======================================================================
 * Course builder (teacher/course_edit.html)
 * ====================================================================== */
.sk-cb-chapters, .sk-cb-lessons { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; }
.sk-cb-chapters { gap: 14px; }
.sk-cb-chapter { display: flex; flex-direction: column; gap: 6px; padding: 12px 12px 10px; border-radius: 20px; background: var(--sk-surface); border: 1px solid var(--sk-border-subtle); box-shadow: var(--sk-shadow-xs); }
.sk-cb-chapter__head { display: flex; align-items: flex-start; gap: 8px; }
.sk-cb-chapter__fields { flex: 1 1 auto; min-width: 0; display: flex; flex-direction: column; gap: 2px; }
.sk-cb-handle { display: grid; place-items: center; flex-shrink: 0; width: 30px; height: 34px; border-radius: 10px; color: var(--sk-fg-subtle); cursor: grab; touch-action: none; }
.sk-cb-handle:hover { background: var(--sk-surface-hover); color: var(--sk-fg); }
.sk-cb-handle:focus-visible { outline: none; box-shadow: var(--sk-focus-ring); }
.sk-cb-handle.is-locked { cursor: default; color: var(--sk-green-10); }
.sk-cb-handle.is-locked:hover { background: transparent; }
.sk-cb-input { width: 100%; min-width: 0; padding: 7px 10px; border: 1px solid transparent; border-radius: 10px; background: transparent; color: var(--sk-fg); font: inherit; font-size: var(--sk-text-sm); transition: border-color var(--sk-dur-fast), background-color var(--sk-dur-fast); }
.sk-cb-input:hover:not(:disabled) { background: var(--sk-surface-sunken); }
.sk-cb-input:focus { outline: none; border-color: var(--sk-brand-8); background: var(--sk-surface); }
.sk-cb-input:disabled { color: var(--sk-fg-muted); }
.sk-cb-input--title { font-family: var(--sk-font-display); font-size: var(--sk-text-md); font-weight: var(--sk-weight-bold); }
.sk-cb-input--desc { font-size: var(--sk-text-xs); color: var(--sk-fg-muted); }
.sk-cb-lessons { gap: 2px; min-height: 8px; margin-left: 30px; padding: 4px 0; }
.sk-cb-lesson { display: flex; align-items: center; gap: 6px; padding: 2px 4px 2px 0; border-radius: 12px; background: var(--sk-surface); }
.sk-cb-lesson:hover { background: var(--sk-surface-sunken); }
.sk-cb-lesson.is-covered .sk-cb-input { color: var(--sk-fg-muted); }
.sk-cb-points { display: inline-flex; align-items: center; gap: 4px; flex-shrink: 0; font-size: var(--sk-text-2xs); font-weight: var(--sk-weight-semibold); color: var(--sk-fg-subtle); }
.sk-cb-points input { width: 52px; padding: 5px 6px; border: 1px solid var(--sk-border); border-radius: 8px; background: var(--sk-surface); color: var(--sk-fg); font: inherit; font-size: var(--sk-text-sm); text-align: center; -moz-appearance: textfield; }
.sk-cb-points input::-webkit-inner-spin-button { appearance: none; }
.sk-cb-points input:disabled { background: transparent; border-color: transparent; color: var(--sk-fg-muted); }
.sk-cb-add { display: flex; align-items: center; gap: 6px; margin-left: 30px; padding: 2px 4px 2px 6px; border-radius: 12px; border: 1px dashed var(--sk-border); }
.sk-cb-add:focus-within { border-style: solid; border-color: var(--sk-brand-7); }
.sk-cb-add__icon { color: var(--sk-fg-subtle); display: inline-flex; }
.sk-cb-new { display: flex; align-items: flex-start; gap: 10px; padding: 14px; border-radius: 20px; border: 1.5px dashed var(--sk-border-strong); }
.sk-cb-new:focus-within { border-color: var(--sk-brand-8); border-style: solid; background: var(--sk-surface); }
.sk-cb-new__icon { display: grid; place-items: center; flex-shrink: 0; width: 36px; height: 36px; border-radius: 12px; background: var(--sk-brand-3); color: var(--sk-brand-11); }
.sk-cb-bar { position: sticky; bottom: calc(12px + var(--sk-safe-bottom, 0px)); z-index: var(--sk-z-sticky); display: flex; align-items: center; gap: 8px; padding: 10px 12px 10px 16px; border-radius: 18px; background: var(--sk-surface-inverse); color: var(--sk-fg-inverse); font-size: var(--sk-text-sm); box-shadow: var(--sk-shadow-xl); }
.sk-app.has-bottomnav .sk-cb-bar { bottom: calc(var(--sk-bottomnav-h, 64px) + 20px + var(--sk-safe-bottom, 0px)); }
.sk-cb-bar .sk-btn--ghost { color: inherit; }
@media (max-width: 559.98px) {
  .sk-cb-lessons, .sk-cb-add { margin-left: 0; }
  .sk-cb-new { flex-wrap: wrap; }
}

/* Question card (ui.question_card): a written question, read only. */
.sk-qcard { display: flex; flex-direction: column; gap: 12px; padding: 14px 16px 16px; border: 1px solid var(--sk-border-subtle); border-radius: var(--sk-radius-lg); background: var(--sk-surface); box-shadow: var(--sk-shadow-xs); }
[data-theme="dark"] .sk-qcard { border-color: var(--sk-border); }
.sk-qcard__head { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.sk-qcard__actions { display: inline-flex; align-items: center; gap: 2px; }
.sk-qcard__actions form { display: contents; }
.sk-qcard__text { margin: 0; font-weight: var(--sk-weight-semibold); font-size: var(--sk-text-md); line-height: 1.45; white-space: pre-line; }
.sk-qcard__options { display: grid; grid-template-columns: 1fr; gap: 8px; margin: 0; padding: 0; list-style: none; }
.sk-qcard__option { display: flex; align-items: center; gap: 10px; min-width: 0; padding: 8px 10px; border: 1px solid var(--sk-border-subtle); border-radius: 12px; background: var(--sk-surface-sunken); font-size: var(--sk-text-sm); }
.sk-qcard__option.is-correct { border-color: var(--sk-green-7); background: var(--sk-green-2); color: var(--sk-green-12); font-weight: var(--sk-weight-semibold); }
.sk-qcard__option.is-correct > .sk-icon { color: var(--sk-green-10); margin-inline-start: auto; flex-shrink: 0; }
.sk-qcard__key { display: grid; place-items: center; width: 24px; height: 24px; border-radius: 50%; background: var(--sk-surface); color: var(--sk-fg-muted); font-size: var(--sk-text-xs); font-weight: var(--sk-weight-bold); flex-shrink: 0; box-shadow: inset 0 0 0 1px var(--sk-border-subtle); }
.sk-qcard__option.is-correct .sk-qcard__key { background: var(--sk-green-9); color: #fff; box-shadow: none; }
.sk-qcard__label { min-width: 0; overflow-wrap: anywhere; }
.sk-qcard__note { display: flex; gap: 8px; align-items: flex-start; margin: 0; padding: 8px 10px; border-radius: 10px; background: var(--sk-surface-sunken); color: var(--sk-fg-muted); font-size: var(--sk-text-sm); }
.sk-qcard__note > .sk-icon { margin-top: 3px; flex-shrink: 0; }
.sk-qcard__note b { color: var(--sk-fg); font-weight: var(--sk-weight-semibold); }
@media (min-width: 560px) { .sk-qcard__options { grid-template-columns: repeat(2, minmax(0, 1fr)); } }