/* ChatKH Rean — lesson pages (extends style.css variables) */
html { scroll-padding-top: 90px; }
body.no-scroll { overflow: hidden; }
[hidden] { display: none !important; }

/* ---------- header bits ---------- */
.header h1 i { margin-right: 6px; }
.platform-switcher { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; margin-top: 22px; }
.platform-tab {
    display: inline-flex; align-items: center; gap: 8px; padding: 8px 18px; border-radius: 999px;
    border: 1.5px solid rgba(255,255,255,.4); color: var(--header-text); text-decoration: none;
    font-weight: 600; font-size: .95rem; background: rgba(255,255,255,.08); transition: background .2s;
}
.platform-tab:hover { background: rgba(255,255,255,.2); }
.platform-tab.active { background: #fff; color: var(--brand-purple); border-color: #fff; }

/* ---------- buttons ---------- */
.btn-primary, .btn-ghost {
    display: inline-flex; align-items: center; gap: 8px; padding: 10px 18px; border-radius: 999px;
    font: 600 .95rem 'Kantumruy Pro', sans-serif; cursor: pointer; text-decoration: none; transition: all .2s;
}
.btn-primary { background: var(--primary-color); color: #fff; border: 2px solid var(--primary-color); }
.btn-primary:hover:not(:disabled) { background: var(--primary-color-dark); border-color: var(--primary-color-dark); }
.btn-ghost { background: transparent; color: var(--text-color); border: 2px solid var(--border-color); }
.btn-ghost:hover:not(:disabled) { border-color: var(--primary-color); color: var(--primary-color); }
.btn-primary:disabled, .btn-ghost:disabled { opacity: .4; cursor: not-allowed; }
.link-btn { background: none; border: 0; padding: 4px 0 0; color: var(--text-secondary-color); font: inherit; font-size: .82rem; cursor: pointer; }
.link-btn:hover { color: var(--primary-color); }

/* ---------- hub ---------- */
.hub-layout { padding-top: 10px; padding-bottom: 50px; }
.announce {
    display: flex; gap: 12px; align-items: flex-start; max-width: 900px; margin: 0 auto 26px; padding: 14px 18px;
    background: rgba(var(--primary-color-rgb), .1); border: 1px solid rgba(var(--primary-color-rgb), .3);
    border-radius: 12px; color: var(--text-color);
}
.announce i { color: var(--primary-color); margin-top: 5px; }
.continue-box { max-width: 900px; margin: 0 auto 30px; }
.continue-box a {
    display: flex; align-items: center; gap: 14px; padding: 14px 20px; border-radius: 14px; text-decoration: none;
    background: var(--bg-secondary-color); border: 1px solid var(--border-color); box-shadow: var(--card-shadow); color: var(--text-color);
}
.continue-box a > i:first-child { width: 40px; height: 40px; flex: none; border-radius: 50%; display: grid; place-items: center; background: var(--primary-color); color: #fff; }
.continue-box span { flex: 1; display: flex; flex-direction: column; min-width: 0; }
.continue-box small { color: var(--text-secondary-color); }
.continue-box strong { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.continue-box a:hover { border-color: var(--primary-color); }

.platform-cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 24px; max-width: 1100px; margin: 0 auto; }
.platform-card {
    display: flex; flex-direction: column; align-items: center; text-align: center; padding: 36px 24px; border-radius: 16px;
    background: var(--bg-secondary-color); border: 1px solid var(--border-color); box-shadow: var(--card-shadow);
    text-decoration: none; color: var(--text-color); transition: transform .2s, box-shadow .2s, border-color .2s;
}
.platform-card:hover { transform: translateY(-6px); box-shadow: var(--card-shadow-hover); border-color: var(--primary-color); }
.platform-icon { width: 72px; height: 72px; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-size: 2rem; color: #fff; margin-bottom: 18px; }
.platform-card h2 { margin: 0 0 10px; font-size: 1.3rem; color: var(--brand-purple); }
[data-theme="dark"] .platform-card h2 { color: var(--brand-orange); }
.platform-card p { font-size: .92rem; color: var(--text-secondary-color); line-height: 1.6; margin: 0 0 16px; flex: 1; }
.platform-status { display: inline-flex; align-items: center; gap: 6px; font-size: .85rem; font-weight: 700; padding: 5px 14px; border-radius: 999px; }
.platform-status.ready { background: rgba(46,204,113,.15); color: #1e8e4e; }
.platform-status.pending { background: rgba(230,168,23,.15); color: #b9770e; }
[data-theme="dark"] .platform-status.ready { color: #6fdd9a; }
[data-theme="dark"] .platform-status.pending { color: #f6be44; }
.hub-progress { width: 100%; margin-top: 14px; }
.hub-progress small { color: var(--text-secondary-color); font-size: .8rem; }

.bar { height: 8px; background: var(--border-color); border-radius: 99px; overflow: hidden; }
.bar span { display: block; height: 100%; width: 0; background: linear-gradient(90deg, var(--brand-orange), #2ecc71); border-radius: 99px; transition: width .4s; }

/* ---------- lesson page layout ---------- */
.lessons-wrap { display: grid; grid-template-columns: 280px minmax(0, 1fr); gap: 30px; align-items: start; padding-bottom: 40px; }
.toc {
    position: sticky; top: 90px; background: var(--bg-secondary-color); border-radius: 14px; padding: 18px;
    box-shadow: var(--card-shadow); border: 1px solid var(--border-color); max-height: calc(100vh - 110px); overflow: auto;
}
.back-to-platforms { display: inline-flex; align-items: center; gap: 6px; font-size: .88rem; text-decoration: none; color: var(--brand-purple); font-weight: 600; margin-bottom: 12px; }
[data-theme="dark"] .back-to-platforms { color: var(--brand-orange); }
.progress-card { background: var(--bg-color); border-radius: 10px; padding: 12px 14px; margin-bottom: 12px; }
.progress-top { display: flex; justify-content: space-between; font-size: .88rem; margin-bottom: 8px; }
.progress-top span { color: var(--text-secondary-color); }
.toc-toggle { display: none; }
.toc-item {
    display: flex; align-items: center; gap: 10px; padding: 9px 10px; margin-bottom: 2px; border-radius: 8px;
    text-decoration: none; color: var(--text-color); font-weight: 500; line-height: 1.4; transition: background .2s;
}
.toc-item > i { width: 20px; text-align: center; color: var(--brand-purple); }
[data-theme="dark"] .toc-item > i { color: var(--brand-orange); }
.toc-item:hover { background: rgba(var(--primary-color-rgb), .1); }
.toc-item.active { background: rgba(var(--primary-color-rgb), .18); font-weight: 700; }
.toc-name { flex: 1; }
.toc-count { font-size: .75rem; padding: 1px 8px; border-radius: 99px; background: var(--bg-color); color: var(--text-secondary-color); border: 1px solid var(--border-color); white-space: nowrap; }
.toc-count.complete { background: #2ecc71; color: #fff; border-color: #2ecc71; }

/* toolbar */
.toolbar {
    position: sticky; top: 71px; z-index: 50; display: flex; flex-wrap: wrap; gap: 12px; align-items: center;
    padding: 12px 0; background: var(--bg-color); border-bottom: 1px solid var(--border-color);
}
.search-box { position: relative; flex: 1 1 260px; }
.search-box i { position: absolute; left: 14px; top: 50%; transform: translateY(-50%); color: var(--text-secondary-color); }
.search-box input {
    width: 100%; box-sizing: border-box; padding: 11px 14px 11px 40px; border-radius: 999px; border: 1.5px solid var(--border-color);
    background: var(--bg-secondary-color); color: var(--text-color); font: inherit; font-size: .95rem;
}
.search-box input:focus { outline: none; border-color: var(--primary-color); }
.filter-chips { display: flex; gap: 8px; flex-wrap: wrap; }
.chip {
    padding: 8px 14px; border-radius: 999px; border: 1.5px solid var(--border-color); background: var(--bg-secondary-color);
    color: var(--text-color); font: 600 .88rem 'Kantumruy Pro', sans-serif; cursor: pointer;
}
.chip.active { background: var(--brand-purple); border-color: var(--brand-purple); color: #fff; }
.no-results { text-align: center; padding: 40px 0; color: var(--text-secondary-color); }

.lesson-section { scroll-margin-top: 140px; }
.lesson-section-title { font-size: 1.6em; display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin-top: 34px; }
.lesson-section-title small { font-size: .5em; font-weight: 600; color: var(--text-secondary-color); background: var(--bg-secondary-color); border: 1px solid var(--border-color); padding: 2px 10px; border-radius: 99px; }

/* cards */
.lesson-grid { gap: 24px; }
.lesson-card { border: 1px solid var(--border-color); scroll-margin-top: 150px; position: relative; }
.lesson-card.is-outdated { opacity: .82; }
.thumb { position: relative; display: block; width: 100%; aspect-ratio: 16/9; padding: 0; border: 0; background: #111; cursor: pointer; overflow: hidden; }
.thumb img { width: 100%; height: 100%; object-fit: cover; display: block; transition: transform .35s; }
.thumb-empty { display: grid; place-items: center; height: 100%; color: #666; font-size: 2rem; }
.lesson-card:hover .thumb img { transform: scale(1.05); }
.thumb .play {
    position: absolute; inset: 0; margin: auto; width: 58px; height: 58px; border-radius: 50%; display: grid; place-items: center;
    background: rgba(0,0,0,.55); color: #fff; font-size: 1.3rem; transition: background .2s, transform .2s;
}
.lesson-card:hover .play { background: var(--primary-color); transform: scale(1.08); }
.thumb .num { position: absolute; left: 10px; bottom: 10px; background: rgba(0,0,0,.65); color: #fff; font-size: .78rem; font-weight: 700; padding: 2px 9px; border-radius: 6px; }
.badges { position: absolute; top: 10px; left: 10px; right: 10px; display: flex; gap: 6px; flex-wrap: wrap; }
.badge { font-size: .74rem; font-weight: 700; padding: 3px 9px; border-radius: 99px; color: #fff; display: inline-flex; gap: 4px; align-items: center; }
.b-new { background: #e74c3c; }
.b-old { background: #7f8c8d; }
.b-done { background: #27ae60; display: none; margin-left: auto; }
.lesson-card.is-done .b-done { display: inline-flex; }
.lesson-card.is-done .thumb img { filter: saturate(.6); }

.lesson-info h3 { font-size: 1.15em; line-height: 1.45; }
.lesson-info p { font-size: .93em; }
.kp-preview { margin: 10px 0 0; padding: 0; list-style: none; font-size: .86em; color: var(--text-secondary-color); }
.kp-preview li { position: relative; padding-left: 18px; margin-bottom: 3px; }
.kp-preview li::before { content: '\f00c'; font-family: 'Font Awesome 6 Free'; font-weight: 900; position: absolute; left: 0; color: #27ae60; font-size: .8em; top: 3px; }
.kp-preview li.more::before { content: ''; }
.kp-preview li.more { font-style: italic; }
.card-foot { margin-top: auto; padding-top: 14px; display: flex; gap: 8px; }
.btn-watch {
    flex: 1; display: inline-flex; justify-content: center; align-items: center; gap: 8px; padding: 9px; border-radius: 10px;
    border: 0; background: rgba(var(--primary-color-rgb), .12); color: var(--primary-color); font: 700 .92rem 'Kantumruy Pro', sans-serif; cursor: pointer;
}
.btn-watch:hover { background: var(--primary-color); color: #fff; }
.btn-mark { width: 42px; border-radius: 10px; border: 1.5px solid var(--border-color); background: transparent; color: var(--text-secondary-color); cursor: pointer; }
.btn-mark:hover { border-color: #27ae60; color: #27ae60; }
.lesson-card.is-done .btn-mark { background: #27ae60; border-color: #27ae60; color: #fff; }

/* empty state */
.empty-state { max-width: 520px; margin: 40px auto 60px; text-align: center; background: var(--bg-secondary-color); padding: 40px 28px; border-radius: 16px; box-shadow: var(--card-shadow); }
.empty-state .platform-icon { margin: 0 auto 18px; }
.empty-state p { color: var(--text-secondary-color); margin-bottom: 22px; }

/* ---------- player ---------- */
.player { position: fixed; inset: 0; z-index: 2000; background: rgba(0,0,0,.85); display: flex; align-items: flex-start; justify-content: center; overflow-y: auto; padding: 30px 16px; }
.player-box { position: relative; width: 100%; max-width: 920px; background: var(--bg-secondary-color); border-radius: 14px; overflow: hidden; animation: pop .25s ease; margin: auto; }
@keyframes pop { from { transform: scale(.96); opacity: 0; } to { transform: none; opacity: 1; } }
.player-close { position: absolute; top: 10px; right: 10px; z-index: 2; width: 38px; height: 38px; border-radius: 50%; border: 0; background: rgba(0,0,0,.6); color: #fff; font-size: 1.1rem; cursor: pointer; }
.player-close:hover { background: var(--primary-color); }
.player-video { aspect-ratio: 16/9; background: #000; }
.player-video iframe { width: 100%; height: 100%; border: 0; display: block; }
.player-body { padding: 20px 24px 24px; }
.player-meta { display: flex; gap: 10px; flex-wrap: wrap; font-size: .82rem; color: var(--text-secondary-color); }
.player-meta span + span::before { content: '•'; margin-right: 10px; }
.player-body h2 { margin: 6px 0 8px; font-size: 1.35rem; color: var(--text-color); }
.player-body > p { color: var(--text-secondary-color); margin: 0 0 14px; }
.player-body h3 { font-size: 1rem; margin: 16px 0 8px; color: var(--brand-purple); }
[data-theme="dark"] .player-body h3 { color: var(--brand-orange); }
.player-body h3 i { color: #f1c40f; }
#playerPoints { margin: 0; padding-left: 22px; color: var(--text-color); }
#playerPoints li { margin-bottom: 6px; }
.old-note { padding: 10px 14px; border-radius: 10px; background: rgba(127,140,141,.15); color: var(--text-color); font-size: .9rem; }
.player-nav { display: flex; gap: 10px; justify-content: space-between; flex-wrap: wrap; margin-top: 20px; padding-top: 16px; border-top: 1px solid var(--border-color); }

/* help button */
.help-fab {
    position: fixed; left: 20px; bottom: 22px; z-index: 990; display: inline-flex; align-items: center; gap: 8px; padding: 10px 16px;
    border-radius: 999px; background: #229ED9; color: #fff; text-decoration: none; font-weight: 600; box-shadow: 0 6px 18px rgba(0,0,0,.2);
}
.help-fab:hover { background: #1b86b8; color: #fff; }

/* ---------- responsive ---------- */
@media (max-width: 992px) {
    .lessons-wrap { grid-template-columns: 1fr; gap: 14px; }
    .toc { position: relative; top: 0; max-height: none; padding: 14px; }
    .toc-toggle {
        display: flex; justify-content: space-between; align-items: center; width: 100%; padding: 10px 14px; border-radius: 10px;
        border: 2px solid var(--primary-color); background: transparent; color: var(--primary-color); font: 600 .95rem 'Kantumruy Pro', sans-serif; cursor: pointer;
    }
    .toc-toggle[aria-expanded="true"] .fa-chevron-down { transform: rotate(180deg); }
    .toc-list { display: none; margin-top: 10px; }
    .toc-list.open { display: block; }
    .toolbar { top: 60px; }
}
@media (max-width: 850px) { .toolbar { top: 60px; } }
@media (max-width: 600px) {
    .help-fab span { display: none; }
    .help-fab { padding: 12px 14px; }
    .player { padding: 0; align-items: stretch; }
    .player-box { border-radius: 0; min-height: 100%; }
    .player-body { padding: 16px; }
    .player-nav .btn-ghost span { display: none; }
    .filter-chips { width: 100%; }
}