/* ==========================================================================
   VAY · Школа ИИ — дизайн-система платформы
   Тёмная тема по умолчанию, светлая — по переключателю или системной настройке
   ========================================================================== */

:root {
  color-scheme: dark;

  --bg:          #08080D;
  --bg-soft:     #0D0D14;
  --surface:     #13131C;
  --surface-2:   #1A1A25;
  --surface-3:   #22222F;
  --border:      #272736;
  --border-soft: #1E1E2A;

  --text:        #F4F5FA;
  --text-2:      #C9CCDA;
  --muted:       #9BA0B4;

  --primary:     #7C6BFF;
  --primary-2:   #9C8BFF;
  --primary-ink: #FFFFFF;
  --primary-dim: rgba(124, 107, 255, .14);
  --accent:      #22D3EE;
  --accent-dim:  rgba(34, 211, 238, .13);
  --success:     #34D399;
  --success-dim: rgba(52, 211, 153, .14);
  --warning:     #FBBF24;
  --danger:      #FB7185;
  --danger-dim:  rgba(251, 113, 133, .14);

  --ring: 0 0 0 3px rgba(124, 107, 255, .45);
  --shadow-1: 0 1px 2px rgba(0,0,0,.4);
  --shadow-2: 0 8px 24px -8px rgba(0,0,0,.55);
  --shadow-3: 0 24px 60px -24px rgba(0,0,0,.75);

  --r-sm: 8px;  --r-md: 12px;  --r-lg: 16px;  --r-xl: 22px;  --r-full: 999px;
  --sp-1: 4px; --sp-2: 8px; --sp-3: 12px; --sp-4: 16px; --sp-5: 24px;
  --sp-6: 32px; --sp-7: 48px; --sp-8: 64px;

  --font: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI",
          Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-num: ui-monospace, SFMono-Regular, "SF Mono", Menlo, monospace;

  --dur: 200ms;
  --ease: cubic-bezier(.22, .61, .36, 1);
  --header-h: 64px;
}

[data-theme="light"] {
  color-scheme: light;
  --bg:          #F5F6FB;
  --bg-soft:     #EFF1F8;
  --surface:     #FFFFFF;
  --surface-2:   #F7F8FC;
  --surface-3:   #EEF0F7;
  --border:      #E1E4EF;
  --border-soft: #EAECF4;
  --text:        #12131C;
  --text-2:      #33364A;
  --muted:       #5C6178;
  --primary:     #5B47E0;
  --primary-2:   #7A66F0;
  --primary-dim: rgba(91, 71, 224, .10);
  --accent:      #0891B2;
  --accent-dim:  rgba(8, 145, 178, .10);
  --success:     #06865A;
  --success-dim: rgba(6, 134, 90, .10);
  --danger:      #D6285A;
  --danger-dim:  rgba(214, 40, 90, .10);
  --shadow-1: 0 1px 2px rgba(16, 20, 40, .06);
  --shadow-2: 0 8px 24px -10px rgba(16, 20, 40, .18);
  --shadow-3: 0 24px 60px -24px rgba(16, 20, 40, .28);
  --ring: 0 0 0 3px rgba(91, 71, 224, .35);
}

/* ---------------------------------------------------------------- база */

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

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  min-height: 100dvh;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  overflow-wrap: break-word;
}

h1, h2, h3, h4 { margin: 0; line-height: 1.25; letter-spacing: -.02em; font-weight: 650; }
p { margin: 0 0 var(--sp-3); }
p:last-child { margin-bottom: 0; }
a { color: var(--primary-2); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; display: block; }

.h1 { font-size: clamp(28px, 5vw, 44px); }
.h2 { font-size: clamp(22px, 3.4vw, 30px); }
.h3 { font-size: 19px; }
.h4 { font-size: 16px; font-weight: 600; }
.muted { color: var(--muted); }
.small { font-size: 13px; }
.tiny { font-size: 12px; }
.num { font-variant-numeric: tabular-nums; font-family: var(--font-num); }
.center { text-align: center; }
.nowrap { white-space: nowrap; }
.hidden { display: none !important; }
.stack { display: grid; gap: var(--sp-3); }
.stack-lg { display: grid; gap: var(--sp-5); }
.row { display: flex; align-items: center; gap: var(--sp-3); flex-wrap: wrap; }
.row-tight { display: flex; align-items: center; gap: var(--sp-2); flex-wrap: wrap; }
.spread { display: flex; align-items: center; justify-content: space-between; gap: var(--sp-3); }
.grow { flex: 1 1 auto; min-width: 0; }
.truncate { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

:where(a, button, input, select, textarea, [tabindex]):focus-visible {
  outline: none;
  box-shadow: var(--ring);
  border-radius: var(--r-sm);
}

.skip-link {
  position: absolute; left: -9999px; top: 8px; z-index: 1000;
  background: var(--primary); color: var(--primary-ink);
  padding: 10px 16px; border-radius: var(--r-md);
}
.skip-link:focus { left: 8px; }

/* ---------------------------------------------------------------- кнопки */

.btn {
  --btn-bg: var(--surface-2);
  --btn-fg: var(--text);
  --btn-bd: var(--border);
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-height: 44px; padding: 10px 18px;
  font: inherit; font-size: 15px; font-weight: 560; line-height: 1;
  color: var(--btn-fg); background: var(--btn-bg);
  border: 1px solid var(--btn-bd); border-radius: var(--r-md);
  cursor: pointer; text-decoration: none;
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease),
              transform 120ms var(--ease), opacity var(--dur) var(--ease);
  -webkit-tap-highlight-color: transparent; touch-action: manipulation;
}
.btn:hover { text-decoration: none; background: var(--surface-3); }
.btn:active { transform: scale(.975); }
.btn[disabled], .btn.is-loading { opacity: .5; pointer-events: none; }

.btn-primary {
  --btn-bg: linear-gradient(135deg, var(--primary) 0%, var(--primary-2) 100%);
  --btn-fg: var(--primary-ink);
  --btn-bd: transparent;
  box-shadow: 0 6px 18px -8px rgba(124, 107, 255, .8);
}
.btn-primary:hover { filter: brightness(1.08); background: linear-gradient(135deg, var(--primary) 0%, var(--primary-2) 100%); }
.btn-ghost { --btn-bg: transparent; --btn-bd: transparent; color: var(--text-2); }
.btn-ghost:hover { background: var(--surface-2); }
.btn-danger { --btn-bg: var(--danger-dim); --btn-fg: var(--danger); --btn-bd: transparent; }
.btn-danger:hover { background: var(--danger-dim); filter: brightness(1.15); }
.btn-success { --btn-bg: var(--success-dim); --btn-fg: var(--success); --btn-bd: transparent; }
.btn-sm { min-height: 36px; padding: 7px 12px; font-size: 13.5px; border-radius: var(--r-sm); }
.btn-lg { min-height: 52px; padding: 14px 26px; font-size: 16.5px; }
.btn-block { width: 100%; }
.btn-icon { min-width: 44px; padding: 10px; }
.btn .spinner { display: none; }
.btn.is-loading .spinner { display: inline-block; }
.btn.is-loading .btn-text { opacity: .6; }

.spinner {
  width: 15px; height: 15px; border-radius: 50%;
  border: 2px solid currentColor; border-top-color: transparent;
  animation: spin .7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------------------------------------------------------------- поля */

.field { display: grid; gap: 6px; }
.field > label { font-size: 13.5px; font-weight: 560; color: var(--text-2); }
.req { color: var(--danger); }

.input, .textarea, .select {
  width: 100%; min-height: 46px; padding: 11px 14px;
  font: inherit; font-size: 15px; color: var(--text);
  background: var(--surface-2);
  border: 1px solid var(--border); border-radius: var(--r-md);
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}
.textarea { min-height: 110px; resize: vertical; line-height: 1.55; }
.input::placeholder, .textarea::placeholder { color: var(--muted); opacity: .8; }
.input:hover, .textarea:hover, .select:hover { border-color: var(--surface-3); }
.input:focus, .textarea:focus, .select:focus {
  outline: none; border-color: var(--primary); box-shadow: var(--ring);
}
.input[aria-invalid="true"] { border-color: var(--danger); }
.hint { font-size: 12.5px; color: var(--muted); }
.error-text { font-size: 13px; color: var(--danger); display: flex; gap: 6px; align-items: flex-start; }

.pw-wrap { position: relative; }
.pw-wrap .input { padding-right: 52px; }
.pw-toggle {
  position: absolute; right: 4px; top: 50%; transform: translateY(-50%);
  width: 44px; height: 40px; display: grid; place-items: center;
  background: none; border: 0; color: var(--muted); cursor: pointer; border-radius: var(--r-sm);
}
.pw-toggle:hover { color: var(--text); }

.check { display: flex; align-items: center; gap: 10px; cursor: pointer; min-height: 44px; }
.check input { width: 20px; height: 20px; accent-color: var(--primary); cursor: pointer; }

/* ---------------------------------------------------------------- карточки */

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  padding: var(--sp-5);
  box-shadow: var(--shadow-1);
}
.card.narrow { max-width: 420px; }
.card-tight { padding: var(--sp-4); }

.badge {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 4px 10px; border-radius: var(--r-full);
  font-size: 12px; font-weight: 600; letter-spacing: .01em;
  background: var(--surface-3); color: var(--text-2); border: 1px solid var(--border-soft);
}
.badge-primary { background: var(--primary-dim); color: var(--primary-2); border-color: transparent; }
.badge-success { background: var(--success-dim); color: var(--success); border-color: transparent; }
.badge-danger  { background: var(--danger-dim);  color: var(--danger);  border-color: transparent; }
.badge-accent  { background: var(--accent-dim);  color: var(--accent);  border-color: transparent; }

.divider { height: 1px; background: var(--border); border: 0; margin: var(--sp-4) 0; }

/* ---------------------------------------------------------------- прогресс */

.progress {
  height: 8px; border-radius: var(--r-full);
  background: var(--surface-3); overflow: hidden;
}
.progress > i {
  display: block; height: 100%; width: 0;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  border-radius: inherit;
  transition: width 500ms var(--ease);
}
@media (prefers-reduced-motion: reduce) {
  .progress > i { transition: none; }
}

/* ---------------------------------------------------------------- шапка */

.topbar {
  position: sticky; top: 0; z-index: 50;
  height: var(--header-h);
  display: flex; align-items: center; gap: var(--sp-4);
  padding: 0 var(--sp-5);
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(160%) blur(14px);
  -webkit-backdrop-filter: saturate(160%) blur(14px);
  border-bottom: 1px solid var(--border);
}
.brand { display: flex; align-items: center; gap: 10px; color: var(--text); font-weight: 680; letter-spacing: -.02em; }
.brand:hover { text-decoration: none; }
.brand-mark {
  width: 34px; height: 34px; border-radius: 10px; flex: none;
  display: grid; place-items: center; color: #fff;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  box-shadow: 0 4px 14px -4px rgba(124, 107, 255, .8);
  font-weight: 800; font-size: 14px; letter-spacing: .02em;
}
.brand-sub { font-size: 12px; font-weight: 500; color: var(--muted); letter-spacing: 0; }

.avatar {
  width: 36px; height: 36px; border-radius: 50%; flex: none;
  display: grid; place-items: center; font-size: 13px; font-weight: 700;
  background: var(--primary-dim); color: var(--primary-2);
  border: 1px solid var(--border);
}

/* ---------------------------------------------------------------- лендинг */

.landing { position: relative; overflow: hidden; min-height: 100dvh; }
.aurora {
  position: absolute; inset: -30% -10% auto -10%; height: 720px; pointer-events: none;
  background:
    radial-gradient(46% 46% at 22% 26%, rgba(124,107,255,.35), transparent 62%),
    radial-gradient(38% 38% at 78% 18%, rgba(34,211,238,.24), transparent 60%),
    radial-gradient(30% 30% at 58% 60%, rgba(167,114,255,.18), transparent 64%);
  filter: blur(30px);
  opacity: .9;
}
[data-theme="light"] .aurora { opacity: .55; }

.wrap { width: 100%; max-width: 1180px; margin: 0 auto; padding: 0 var(--sp-5); }
.hero { position: relative; padding: clamp(40px, 8vw, 86px) 0 var(--sp-8); }
.hero-grid { display: grid; gap: clamp(28px, 5vw, 56px); grid-template-columns: 1fr; align-items: start; }
@media (min-width: 940px) { .hero-grid { grid-template-columns: 1.08fr .92fr; } }

.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 6px 14px; border-radius: var(--r-full);
  background: var(--surface-2); border: 1px solid var(--border);
  font-size: 13px; color: var(--text-2); font-weight: 540;
}
.hero h1 { margin: var(--sp-4) 0 var(--sp-4); font-size: clamp(32px, 5.6vw, 54px); font-weight: 700; }
.hero h1 .grad {
  background: linear-gradient(120deg, var(--primary-2), var(--accent));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.lead { font-size: clamp(16px, 2vw, 19px); color: var(--text-2); max-width: 58ch; }

.feature-grid { display: grid; gap: var(--sp-3); grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); margin-top: var(--sp-6); }
.feature {
  display: flex; gap: 12px; padding: var(--sp-4);
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--r-lg);
}
.feature-ic {
  width: 38px; height: 38px; flex: none; border-radius: 11px; display: grid; place-items: center;
  background: var(--primary-dim); color: var(--primary-2);
}
.feature h3 { font-size: 15px; margin-bottom: 2px; }
.feature p { font-size: 13.5px; color: var(--muted); margin: 0; }

.login-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--r-xl); padding: clamp(22px, 3vw, 32px);
  box-shadow: var(--shadow-3);
  position: relative;
}
.login-card::before {
  content: ""; position: absolute; inset: -1px; border-radius: inherit; pointer-events: none;
  background: linear-gradient(150deg, rgba(124,107,255,.5), transparent 42%);
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor; mask-composite: exclude; padding: 1px;
}

.site-footer {
  border-top: 1px solid var(--border); margin-top: var(--sp-8);
  padding: var(--sp-5) 0; color: var(--muted); font-size: 13.5px;
}

.center-page { display: grid; place-items: center; min-height: 100dvh; padding: var(--sp-5); }

/* ---------------------------------------------------------------- кабинет */

.shell { display: grid; grid-template-columns: 1fr; min-height: 100dvh; }
@media (min-width: 1024px) { .shell { grid-template-columns: 320px 1fr; } }

.sidebar {
  border-right: 1px solid var(--border);
  background: var(--bg-soft);
  padding: var(--sp-4);
  display: none;
}
@media (min-width: 1024px) {
  .sidebar { display: block; position: sticky; top: var(--header-h); height: calc(100dvh - var(--header-h)); overflow-y: auto; }
}
.sidebar.is-open {
  display: block; position: fixed; inset: var(--header-h) 0 0 0; z-index: 60;
  overflow-y: auto; background: var(--bg);
}

.main { padding: var(--sp-5) var(--sp-5) var(--sp-8); min-width: 0; }
@media (min-width: 1024px) { .main { padding: var(--sp-6) clamp(24px, 4vw, 48px) var(--sp-8); } }
.main-narrow { max-width: 940px; margin: 0 auto; }

.module-block { margin-bottom: var(--sp-5); }
.module-head {
  display: flex; align-items: center; gap: 10px; width: 100%;
  padding: 10px 12px; margin-bottom: 6px;
  background: none; border: 0; border-radius: var(--r-md);
  font: inherit; font-size: 13px; font-weight: 700; letter-spacing: .04em;
  text-transform: uppercase; color: var(--muted); cursor: pointer; text-align: left;
}
.module-head:hover { background: var(--surface-2); color: var(--text-2); }
.module-head .chev { transition: transform var(--dur) var(--ease); }
.module-head[aria-expanded="false"] .chev { transform: rotate(-90deg); }

.lesson-link {
  display: flex; align-items: center; gap: 10px;
  min-height: 44px; padding: 9px 12px; border-radius: var(--r-md);
  color: var(--text-2); font-size: 14.5px; border: 1px solid transparent;
  transition: background var(--dur) var(--ease), color var(--dur) var(--ease);
}
.lesson-link:hover { background: var(--surface-2); color: var(--text); text-decoration: none; }
.lesson-link[aria-current="true"] {
  background: var(--primary-dim); color: var(--text); border-color: color-mix(in srgb, var(--primary) 40%, transparent);
  font-weight: 560;
}
.lesson-dot {
  width: 20px; height: 20px; flex: none; border-radius: 50%;
  border: 1.5px solid var(--border); display: grid; place-items: center;
  color: var(--success); background: var(--surface);
}
.lesson-link.done .lesson-dot { border-color: transparent; background: var(--success-dim); }

/* карточки уроков */
.lesson-cards { display: grid; gap: var(--sp-4); grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); }
.lesson-card {
  display: flex; flex-direction: column;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--r-lg); overflow: hidden; color: var(--text);
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}
.lesson-card:hover { text-decoration: none; transform: translateY(-3px); border-color: color-mix(in srgb, var(--primary) 45%, var(--border)); box-shadow: var(--shadow-2); }
.lesson-card:active { transform: translateY(-1px); }
.thumb {
  position: relative; aspect-ratio: 16 / 9; background: var(--surface-3);
  display: grid; place-items: center; color: var(--muted); overflow: hidden;
}
.thumb img { width: 100%; height: 100%; object-fit: cover; }
.thumb::after {
  content: ""; position: absolute; inset: 0;
  background: linear-gradient(160deg, rgba(124,107,255,.20), rgba(34,211,238,.10));
}
.thumb .play-badge {
  position: absolute; z-index: 1; width: 52px; height: 52px; border-radius: 50%;
  display: grid; place-items: center; color: #fff;
  background: rgba(12,12,20,.55); backdrop-filter: blur(6px);
  border: 1px solid rgba(255,255,255,.18);
}
.lesson-card-body { padding: var(--sp-4); display: grid; gap: 6px; align-content: start; flex: 1; }
.lesson-card-body h3 { font-size: 15.5px; }

/* плеер */
.player-frame {
  position: relative; border-radius: var(--r-lg); overflow: hidden;
  background: #000; border: 1px solid var(--border); aspect-ratio: 16 / 9;
}
.player-frame video, .player-frame iframe { width: 100%; height: 100%; border: 0; display: block; }
.wm {
  position: absolute; right: 12px; bottom: 12px; z-index: 2; pointer-events: none;
  font-size: 11px; letter-spacing: .02em; color: rgba(255,255,255,.62);
  background: rgba(0,0,0,.35); padding: 4px 9px; border-radius: var(--r-full);
  backdrop-filter: blur(4px);
}
.player-empty {
  display: grid; place-items: center; gap: 10px; color: var(--muted);
  height: 100%; text-align: center; padding: var(--sp-5);
}

.prose { color: var(--text-2); font-size: 15.5px; line-height: 1.7; white-space: pre-wrap; }
.prose a { text-decoration: underline; }

.material {
  display: flex; align-items: center; gap: 12px; min-height: 56px;
  padding: 10px 14px; border: 1px solid var(--border); border-radius: var(--r-md);
  background: var(--surface); color: var(--text);
}
.material:hover { text-decoration: none; border-color: var(--primary); background: var(--surface-2); }

/* ---------------------------------------------------------------- админка */

.tabs {
  display: flex; gap: 4px; overflow-x: auto; padding: 4px;
  background: var(--surface-2); border: 1px solid var(--border);
  border-radius: var(--r-md); scrollbar-width: none;
}
.tabs::-webkit-scrollbar { display: none; }
.tab {
  display: inline-flex; align-items: center; gap: 8px; white-space: nowrap;
  min-height: 40px; padding: 8px 15px; border: 0; border-radius: var(--r-sm);
  background: none; color: var(--muted); font: inherit; font-size: 14px; font-weight: 560;
  cursor: pointer; transition: background var(--dur) var(--ease), color var(--dur) var(--ease);
}
.tab:hover { color: var(--text); background: var(--surface-3); }
.tab[aria-selected="true"] { background: var(--surface); color: var(--text); box-shadow: var(--shadow-1); }

.stat-grid { display: grid; gap: var(--sp-3); grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); }
.stat { padding: var(--sp-4); background: var(--surface); border: 1px solid var(--border); border-radius: var(--r-lg); }
.stat-v { font-size: 28px; font-weight: 700; letter-spacing: -.03em; font-variant-numeric: tabular-nums; }
.stat-l { font-size: 13px; color: var(--muted); }

.table-wrap { overflow-x: auto; border: 1px solid var(--border); border-radius: var(--r-lg); background: var(--surface); }
table.tbl { width: 100%; border-collapse: collapse; font-size: 14px; min-width: 640px; }
table.tbl th, table.tbl td { padding: 12px 14px; text-align: left; border-bottom: 1px solid var(--border-soft); vertical-align: middle; }
table.tbl th { font-size: 12.5px; text-transform: uppercase; letter-spacing: .04em; color: var(--muted); font-weight: 650; background: var(--surface-2); position: sticky; top: 0; }
table.tbl tbody tr:last-child td { border-bottom: 0; }
table.tbl tbody tr:hover { background: var(--surface-2); }

.admin-lesson {
  display: flex; align-items: center; gap: 12px; padding: 12px 14px;
  border: 1px solid var(--border); border-radius: var(--r-md); background: var(--surface-2);
}
.handle { color: var(--muted); cursor: grab; display: grid; place-items: center; width: 28px; height: 40px; }
.admin-lesson.drag-over { border-color: var(--primary); background: var(--primary-dim); }
.admin-lesson.dragging { opacity: .4; }

.empty {
  display: grid; place-items: center; gap: 10px; text-align: center;
  padding: var(--sp-7) var(--sp-4); color: var(--muted);
  border: 1px dashed var(--border); border-radius: var(--r-lg); background: var(--surface);
}

/* ---------------------------------------------------------------- модалки и тосты */

.modal-back {
  position: fixed; inset: 0; z-index: 200; display: grid; place-items: center;
  padding: var(--sp-4); background: rgba(6, 6, 12, .62);
  backdrop-filter: blur(4px); animation: fade 160ms var(--ease);
  overflow-y: auto;
}
.modal {
  width: min(620px, 100%); max-height: 92dvh; overflow-y: auto;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--r-xl); box-shadow: var(--shadow-3);
  animation: pop 200ms var(--ease);
}
.modal-head { display: flex; align-items: center; justify-content: space-between; gap: var(--sp-3); padding: var(--sp-5) var(--sp-5) 0; }
.modal-body { padding: var(--sp-5); display: grid; gap: var(--sp-4); }
.modal-foot { display: flex; gap: var(--sp-2); justify-content: flex-end; flex-wrap: wrap; padding: 0 var(--sp-5) var(--sp-5); }
@keyframes fade { from { opacity: 0; } }
@keyframes pop { from { opacity: 0; transform: translateY(12px) scale(.98); } }

.toasts {
  position: fixed; z-index: 300; right: 16px; bottom: 16px;
  display: grid; gap: 8px; width: min(380px, calc(100vw - 32px));
}
.toast {
  display: flex; align-items: flex-start; gap: 10px;
  padding: 13px 15px; border-radius: var(--r-md);
  background: var(--surface); border: 1px solid var(--border);
  box-shadow: var(--shadow-3); font-size: 14.5px;
  animation: slide 220ms var(--ease);
}
.toast.ok { border-left: 3px solid var(--success); }
.toast.err { border-left: 3px solid var(--danger); }
@keyframes slide { from { opacity: 0; transform: translateY(10px); } }

.copy-box {
  display: flex; align-items: center; gap: 10px; padding: 12px 14px;
  background: var(--surface-2); border: 1px dashed var(--border); border-radius: var(--r-md);
  font-family: var(--font-num); font-size: 15px; word-break: break-all;
}

.skeleton {
  background: linear-gradient(90deg, var(--surface-2) 25%, var(--surface-3) 37%, var(--surface-2) 63%);
  background-size: 400% 100%; animation: shimmer 1.3s ease infinite;
  border-radius: var(--r-md);
}
@keyframes shimmer { 0% { background-position: 100% 0; } 100% { background-position: 0 0; } }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .01ms !important; animation-iteration-count: 1 !important;
    transition-duration: .01ms !important; scroll-behavior: auto !important;
  }
}

@media (max-width: 640px) {
  .topbar { padding: 0 var(--sp-4); gap: var(--sp-3); }
  .main { padding: var(--sp-4) var(--sp-4) var(--sp-7); }
  .card { padding: var(--sp-4); }
  .modal-body, .modal-head, .modal-foot { padding-left: var(--sp-4); padding-right: var(--sp-4); }
  .toasts { right: 8px; left: 8px; bottom: 8px; width: auto; }
}

/* ---------------------------------------------------------------- ИИ-наставник */

.tutor {
  border: 1px solid var(--border); border-radius: var(--r-lg);
  background: var(--surface); overflow: hidden;
}
.tutor-head {
  display: flex; align-items: center; gap: 12px;
  padding: var(--sp-4); border-bottom: 1px solid var(--border-soft);
  background: linear-gradient(120deg, var(--primary-dim), transparent 70%);
}
.tutor-ava {
  width: 40px; height: 40px; border-radius: 12px; flex: none;
  display: grid; place-items: center; color: #fff;
  background: linear-gradient(135deg, var(--primary), var(--accent));
}
.tutor-log {
  display: grid; gap: 12px; padding: var(--sp-4);
  max-height: 460px; overflow-y: auto; scroll-behavior: smooth;
}
.msg { display: flex; gap: 10px; max-width: 90%; }
.msg-ai { align-self: flex-start; }
.msg-me { align-self: flex-end; flex-direction: row-reverse; }
.msg-body {
  padding: 11px 14px; border-radius: 14px; font-size: 15px; line-height: 1.6;
  white-space: pre-wrap; overflow-wrap: anywhere;
}
.msg-ai .msg-body { background: var(--surface-2); border: 1px solid var(--border-soft);
                    border-bottom-left-radius: 5px; }
.msg-me .msg-body { background: var(--primary-dim); border: 1px solid transparent;
                    border-bottom-right-radius: 5px; color: var(--text); }
.msg-ic {
  width: 28px; height: 28px; flex: none; border-radius: 9px; display: grid; place-items: center;
  background: var(--surface-3); color: var(--primary-2); font-size: 11px; font-weight: 700;
}
.tutor-form { display: flex; gap: 8px; padding: var(--sp-4); border-top: 1px solid var(--border-soft); }
.tutor-form .textarea { min-height: 46px; max-height: 140px; }
.typing { display: inline-flex; gap: 4px; align-items: center; padding: 4px 0; }
.typing i {
  width: 6px; height: 6px; border-radius: 50%; background: var(--muted);
  animation: blink 1.2s infinite;
}
.typing i:nth-child(2) { animation-delay: .18s; }
.typing i:nth-child(3) { animation-delay: .36s; }
@keyframes blink { 0%, 60%, 100% { opacity: .25; } 30% { opacity: 1; } }

.hw-result {
  display: grid; gap: 10px; padding: var(--sp-4);
  border-radius: var(--r-md); border: 1px solid var(--border);
  background: var(--surface-2);
}
.hw-score {
  display: inline-flex; align-items: baseline; gap: 4px;
  font-size: 26px; font-weight: 700; font-variant-numeric: tabular-nums;
}
.hw-score span { font-size: 13px; font-weight: 500; color: var(--muted); }