/* ============================================================
   Educatone — Cabinet shell (sidebar + header + layout)
   Shared across: courses, course, lesson
   ============================================================ */

.app {
  display: grid;
  grid-template-columns: var(--sidebar-w) 1fr;
  min-height: 100dvh;
}

/* ===================== Sidebar ===================== */
.sidebar {
  position: sticky; top: 0; align-self: start;
  height: 100dvh;
  background: var(--surface);
  border-right: 1px solid var(--border);
  display: flex; flex-direction: column;
  padding: var(--space-5) var(--space-4);
  z-index: 40;
  /* Menu stays fixed in place; if it's taller than the viewport it scrolls
     internally to its end instead of being clipped by the page. */
  overflow-y: auto;
  overscroll-behavior: contain;
}
.sidebar__logo { display: flex; align-items: center; gap: 11px; padding: var(--space-2) var(--space-2) var(--space-6); }
.sidebar__logo .mark { width: 36px; height: 36px; border-radius: 10px; background: var(--color-primary); display: grid; place-items: center; box-shadow: var(--shadow-primary); }
.sidebar__logo span { font-size: 19px; font-weight: 800; letter-spacing: -.02em; }

.nav-group { display: flex; flex-direction: column; gap: 2px; }
.nav-group + .nav-group { margin-top: var(--space-5); }
.nav-group__title { font-size: 11.5px; font-weight: 700; text-transform: uppercase; letter-spacing: .06em; color: var(--text-muted); padding: 0 var(--space-3) var(--space-2); }

.nav-item {
  display: flex; align-items: center; gap: 12px;
  height: 44px; padding: 0 var(--space-3);
  border-radius: var(--r-md); color: var(--text-soft); font-size: 14.5px; font-weight: 500;
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease);
}
.nav-item svg { width: 20px; height: 20px; flex-shrink: 0; }
.nav-item:hover { background: var(--surface-2); color: var(--text); }
.nav-item.is-active { background: var(--color-primary-soft); color: var(--color-primary-hover); font-weight: 600; }
.nav-item .count { margin-left: auto; font-size: 12px; font-weight: 700; background: var(--surface-2); color: var(--text-soft); border-radius: var(--r-full); padding: 2px 8px; }
.nav-item.is-active .count { background: #fff; color: var(--color-primary-hover); }

.sidebar__spacer { flex: 1; }

.sidebar__progress {
  background: linear-gradient(135deg, #4F46E5, #4338CA);
  color: #fff; border-radius: var(--r-lg); padding: var(--space-4); margin-bottom: var(--space-4);
  position: relative; overflow: hidden;
}
.sidebar__progress h4 { font-size: 14px; font-weight: 700; }
.sidebar__progress p { font-size: 12.5px; color: rgba(255,255,255,.8); margin: 4px 0 12px; }
.sidebar__progress .bar { height: 7px; border-radius: 99px; background: rgba(255,255,255,.25); overflow: hidden; }
.sidebar__progress .bar > span { display: block; height: 100%; background: #fff; border-radius: 99px; }
.sidebar__progress .pct { margin-top: 8px; font-size: 12px; font-weight: 700; }

.sidebar__user { display: flex; align-items: center; gap: 11px; padding: var(--space-3); border-radius: var(--r-md); transition: background var(--dur); cursor: pointer; }
.sidebar__user:hover { background: var(--surface-2); }
.avatar { width: 38px; height: 38px; border-radius: 50%; background: var(--color-primary-soft); color: var(--color-primary-hover); display: grid; place-items: center; font-weight: 700; font-size: 14px; flex-shrink: 0; }
.sidebar__user .meta { min-width: 0; }
.sidebar__user .meta b { font-size: 14px; font-weight: 600; display: block; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.sidebar__user .meta small { font-size: 12.5px; color: var(--text-muted); }

/* ===================== Header ===================== */
.main { min-width: 0; display: flex; flex-direction: column; }
.header {
  position: sticky; top: 0; z-index: 30;
  height: var(--header-h);
  background: rgba(248,250,252,.85); backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  display: flex; align-items: center; gap: var(--space-4);
  padding: 0 var(--space-8);
}
.header__burger { display: none; width: 40px; height: 40px; border-radius: var(--r-md); border: 1px solid var(--border); background: var(--surface); color: var(--text); place-items: center; }
.header__title { font-size: 20px; font-weight: 700; letter-spacing: -.02em; }
.header__spacer { flex: 1; }

.search {
  position: relative; width: 320px; max-width: 40vw;
}
.search svg { position: absolute; left: 12px; top: 50%; transform: translateY(-50%); width: 18px; height: 18px; color: var(--text-muted); }
.search input {
  height: 42px; width: 100%; padding: 0 var(--space-4) 0 40px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--r-md);
  font-size: 14px; color: var(--text);
}
.search input:focus { outline: none; border-color: var(--color-primary); box-shadow: 0 0 0 4px var(--color-primary-ring); }

.icon-btn { position: relative; width: 42px; height: 42px; border-radius: var(--r-md); border: 1px solid var(--border); background: var(--surface); color: var(--text-soft); display: grid; place-items: center; transition: background var(--dur), color var(--dur); }
.icon-btn:hover { background: var(--surface-2); color: var(--text); }
.icon-btn .dot { position: absolute; top: 9px; right: 10px; width: 8px; height: 8px; border-radius: 50%; background: var(--color-danger); border: 2px solid var(--surface); }

.streak { display: flex; align-items: center; gap: 7px; height: 42px; padding: 0 14px; border-radius: var(--r-md); background: var(--color-warning-soft); color: #B45309; font-weight: 700; font-size: 14px; }

/* ===================== Bell (notifications) ===================== */
.bell { position: relative; }
.bell__dot { position: absolute; top: 4px; right: 4px; min-width: 17px; height: 17px; padding: 0 4px; border-radius: 99px; background: var(--color-danger); color: #fff; font-size: 10.5px; font-weight: 700; line-height: 17px; text-align: center; border: 2px solid var(--surface); }
.bell__menu { position: absolute; top: calc(100% + 10px); right: 0; width: 360px; max-width: calc(100vw - 32px); background: var(--surface); border: 1px solid var(--border); border-radius: var(--r-lg); box-shadow: var(--shadow-lg); opacity: 0; visibility: hidden; transform: translateY(-6px); transition: opacity var(--dur) var(--ease), transform var(--dur) var(--ease), visibility var(--dur); z-index: 200; overflow: hidden; }
.bell.open .bell__menu { opacity: 1; visibility: visible; transform: translateY(0); }
.bell__head { display: flex; align-items: center; justify-content: space-between; padding: 14px 16px; border-bottom: 1px solid var(--border); }
.bell__head b { font-size: 15px; font-weight: 700; }
.bell__mark { font-size: 12.5px; color: var(--color-primary); font-weight: 600; }
.bell__list { max-height: 380px; overflow-y: auto; }
.bell__empty { padding: 34px 16px; text-align: center; color: var(--text-soft); font-size: 14px; }
.bell__item { display: flex; gap: 11px; padding: 13px 16px; border-bottom: 1px solid var(--border); transition: background var(--dur); }
.bell__item:last-child { border-bottom: 0; }
.bell__item:hover { background: var(--surface-2); }
.bell__item.is-unread { background: var(--color-primary-soft); }
.bell__item.is-unread:hover { background: var(--color-primary-soft); }
.bell__ico { flex: none; width: 32px; height: 32px; border-radius: 50%; background: var(--color-primary-soft); color: var(--color-primary-hover); display: grid; place-items: center; }
.bell__item.is-unread .bell__ico { background: #fff; }
.bell__body { min-width: 0; }
.bell__body b { display: block; font-size: 13.5px; font-weight: 600; color: var(--text); }
.bell__body span { display: block; font-size: 12.5px; color: var(--text-soft); margin-top: 2px; line-height: 1.4; }
.bell__body time { display: block; font-size: 11.5px; color: var(--text-muted); margin-top: 4px; }
.bell__all { display: block; padding: 12px 16px; text-align: center; font-size: 13px; font-weight: 600; color: var(--color-primary); border-top: 1px solid var(--border); }
.bell__all:hover { background: var(--surface-2); }

/* ===================== Content ===================== */
.content { padding: var(--space-8); max-width: var(--container); width: 100%; }

/* ===================== Mobile nav ===================== */
.scrim { display: none; position: fixed; inset: 0; background: rgba(15,23,42,.5); z-index: 45; }

@media (max-width: 1024px) {
  .app { grid-template-columns: 1fr; }
  .sidebar {
    position: fixed; left: 0; top: 0; width: 280px;
    transform: translateX(-100%); transition: transform var(--dur) var(--ease);
    box-shadow: var(--shadow-lg);
  }
  .app.nav-open .sidebar { transform: translateX(0); }
  .app.nav-open .scrim { display: block; }
  .header__burger { display: grid; }
  .header { padding: 0 var(--space-5); }
  .content { padding: var(--space-6) var(--space-5); }
}
@media (max-width: 640px) {
  .search { display: none; }
  .header__title { font-size: 18px; }
  .streak { display: none; }
}

/* ============================================================
   Shared info components (progress ring, achievements,
   leaderboard, deadlines) — used by course design variants
   ============================================================ */
.info-card { padding: var(--space-6); }
.info-card__head { display: flex; align-items: center; justify-content: space-between; margin-bottom: var(--space-5); }
.info-card__head h4 { font-size: 16px; font-weight: 700; letter-spacing: -.01em; }
.info-card__head a { font-size: 13px; font-weight: 600; color: var(--color-primary); }
.info-card__head a:hover { text-decoration: underline; }

/* Progress ring */
.ring { display: flex; align-items: center; gap: var(--space-5); }
.ring__circle { width: 84px; height: 84px; border-radius: 50%; flex-shrink: 0; position: relative; display: grid; place-items: center;
  background: conic-gradient(var(--color-primary) calc(var(--p,58)*1%), var(--surface-2) 0); }
.ring__circle::before { content: ""; position: absolute; width: 64px; height: 64px; border-radius: 50%; background: var(--surface); }
.ring__circle b { position: relative; font-size: 19px; font-weight: 800; }
.ring__txt b { font-size: 16px; font-weight: 700; } .ring__txt small { display: block; color: var(--text-muted); font-size: 13.5px; margin-top: 3px; }

/* Achievements */
.medals { display: flex; gap: var(--space-4); }
.medal { flex: 1; text-align: center; }
.medal .disc { width: 54px; height: 54px; margin: 0 auto 9px; border-radius: 16px; display: grid; place-items: center; }
.medal small { font-size: 12.5px; color: var(--text-soft); line-height: 1.3; display: block; }
.medal.lock .disc { background: var(--surface-2); color: var(--text-muted); }
.medal.lock small { color: var(--text-muted); }

/* Leaderboard */
.lb { display: flex; flex-direction: column; gap: var(--space-3); }
.lb__row { display: flex; align-items: center; gap: 12px; font-size: 14.5px; }
.lb__pos { width: 24px; font-weight: 800; color: var(--text-muted); text-align: center; flex-shrink: 0; }
.lb__pos.top { color: var(--color-warning); }
.lb__av { width: 34px; height: 34px; border-radius: 50%; background: var(--surface-2); display: grid; place-items: center; font-size: 12.5px; font-weight: 700; color: var(--text-soft); flex-shrink: 0; }
.lb__name { flex: 1; min-width: 0; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.lb__pts { font-weight: 700; color: var(--text-soft); }
.lb__row.me { background: var(--color-primary-soft); margin: 0 -10px; padding: 8px 10px; border-radius: var(--r-md); }
.lb__row.me .lb__pos, .lb__row.me .lb__pts { color: var(--color-primary-hover); }
.lb__row.me .lb__av { background: var(--color-primary); color: #fff; }
.lb__row.me .lb__name { font-weight: 700; }

/* Deadlines */
.dl { display: flex; flex-direction: column; gap: var(--space-4); }
.dl__row { display: flex; align-items: center; gap: 12px; }
.dl__mark { width: 10px; height: 10px; border-radius: 50%; flex-shrink: 0; }
.dl__info { flex: 1; min-width: 0; }
.dl__info b { font-size: 14.5px; font-weight: 600; display: block; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.dl__info small { font-size: 12.5px; color: var(--text-muted); }
.dl__when { font-size: 12.5px; font-weight: 700; padding: 4px 11px; border-radius: var(--r-full); flex-shrink: 0; }
.dl__when.soon { background: var(--color-danger-soft); color: #B91C1C; }
.dl__when.week { background: var(--color-warning-soft); color: #B45309; }
.dl__when.later { background: var(--surface-2); color: var(--text-soft); }

/* KPI tile */
.kpi { padding: var(--space-5); display: flex; align-items: center; gap: var(--space-4); }
.kpi__ico { width: 46px; height: 46px; border-radius: 13px; display: grid; place-items: center; flex-shrink: 0; }
.kpi__ico svg { width: 22px; height: 22px; }
.kpi b { font-size: 22px; font-weight: 800; letter-spacing: -.02em; display: block; line-height: 1.1; }
.kpi span { font-size: 13px; color: var(--text-soft); }

/* Shared switch + segmented choice (used on student & admin settings) */
.switch { width: 46px; height: 26px; border-radius: 99px; background: var(--border-strong); position: relative; cursor: pointer; transition: background var(--dur); flex-shrink: 0; border: none; }
.switch::after { content: ""; position: absolute; top: 3px; left: 3px; width: 20px; height: 20px; border-radius: 50%; background: #fff; transition: transform var(--dur) var(--ease); box-shadow: var(--shadow-xs); }
.switch.on { background: var(--color-primary); } .switch.on::after { transform: translateX(20px); }
.seg-choice { display: inline-flex; background: var(--surface-2); border-radius: var(--r-md); padding: 4px; }
.seg-choice button { border: none; background: transparent; height: 34px; padding: 0 14px; border-radius: var(--r-sm); font-size: 13px; font-weight: 600; color: var(--text-soft); }
.seg-choice button.on { background: var(--surface); box-shadow: var(--shadow-xs); color: var(--color-primary-hover); }