.ac-track { padding: 6px 10px 2px; }
.ac-track h4 { font-size: 12px; color: var(--accent); margin: 12px 6px 4px; display: flex; gap: 6px; align-items: center; }
.ac-track h4 span.ic { font-size: 14px; }
.ac-lesson { padding: 8px 10px; margin: 2px 0; border-radius: 7px; cursor: pointer; font-size: 12.5px; color: var(--muted); }
.ac-lesson:hover { background: var(--bg2); color: var(--text); }
.ac-lesson.active { background: #1b2c4b; color: var(--text); border-left: 2px solid var(--accent); }
.ac-lesson .meta { font-size: 10.5px; color: var(--muted); margin-top: 2px; }
.ac-lesson .tag { font-size: 9px; padding: 1px 5px; border-radius: 999px; background: var(--bg2); border: 1px solid var(--line); margin-left: 4px; }
.lesson { max-width: 820px; }
.lesson h2 { font-size: 22px; margin: 0 0 4px; }
.lesson .lead { color: var(--muted); font-size: 13.5px; margin-bottom: 16px; }
.lesson-body { font-size: 14px; line-height: 1.7; color: #d8e3f3; }
.lesson-body h4 { color: var(--accent); font-size: 15px; margin: 22px 0 6px; }
.lesson-body p { margin: 8px 0; }
.lesson-body ul, .lesson-body ol { margin: 8px 0 8px 4px; padding-left: 22px; }
.lesson-body li { margin: 5px 0; }
.lesson-body b { color: #fff; }
.formula { display: inline-block; background: #16243f; border: 1px solid var(--line2); border-radius: 5px; padding: 1px 8px; font-family: "Cascadia Code", Consolas, monospace; font-size: 13px; color: #9fe0ff; }
.callout { background: linear-gradient(180deg, #16243f, #14213a); border-left: 3px solid var(--accent); border-radius: 0 8px 8px 0; padding: 11px 14px; margin: 14px 0; font-size: 13px; }
.dos, .donts { border-radius: 9px; padding: 12px 14px; margin: 12px 0; }
.dos { background: rgba(56, 211, 159, .08); border: 1px solid #2a5a44; }
.donts { background: rgba(255, 107, 107, .07); border: 1px solid #5a2a2a; }
.dos > b { color: var(--good); } .donts > b { color: var(--bad); }
.lesson-body table.tbl { margin: 12px 0; }
.anim-wrap { margin: 16px 0; }
.calc-widget { background: var(--panel); border: 1px solid var(--line2); border-radius: 10px; padding: 16px; margin: 18px 0; }
.calc-widget h4 { color: var(--accent); margin: 0 0 10px; }
.calc-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 10px; }
.ac-home { max-width: 900px; }
.ac-home .cards { margin-top: 14px; }
.ac-home .card h4 { font-size: 16px; }
.ac-pager { display: flex; justify-content: space-between; margin-top: 26px; border-top: 1px solid var(--line); padding-top: 14px; }
.progbar { height: 5px; background: var(--bg2); border-radius: 4px; margin: 4px 6px 6px; overflow: hidden; }
.progbar > span { display: block; height: 100%; background: linear-gradient(90deg, var(--accent), var(--good)); border-radius: 4px; transition: width .3s; }
.ac-lesson .tick { display: inline-block; width: 14px; color: var(--muted); }
.ac-lesson .tick.on { color: var(--good); }
.done-badge { font-size: 12px; color: var(--good); border: 1px solid #2a5a44; border-radius: 999px; padding: 2px 9px; vertical-align: middle; margin-left: 8px; }
.quiz-q { margin: 10px 0 14px; }
.quiz-qt { font-weight: 600; font-size: 13px; margin-bottom: 6px; }
.quiz-opt { display: block; padding: 7px 11px; margin: 4px 0; background: var(--bg2); border: 1px solid var(--line); border-radius: 7px; cursor: pointer; font-size: 12.5px; }
.quiz-opt:hover { border-color: var(--accent2); }
.quiz-opt input { width: auto; margin-right: 8px; }
.quiz-opt.correct { border-color: var(--good); background: rgba(56, 211, 159, .1); }
.quiz-opt.wrong { border-color: var(--bad); background: rgba(255, 107, 107, .1); }
.deck-wrap { max-width: 1000px; }
.deck-stage { position: relative; width: 100%; aspect-ratio: 16 / 9; background: #0a1222; border: 1px solid var(--line); border-radius: 10px; overflow: hidden; box-shadow: var(--shadow); }
.deck-slide { width: 100%; height: 100%; display: block; }
.deck-gif { position: absolute; object-fit: fill; border-radius: 6px; }
.deck-ctrl { display: flex; align-items: center; justify-content: center; gap: 14px; margin: 12px 0; }
.deck-thumbs { display: grid; grid-template-columns: repeat(auto-fill, minmax(110px, 1fr)); gap: 8px; }
.deck-thumb { width: 100%; border-radius: 6px; border: 2px solid transparent; cursor: pointer; display: block; }
.deck-thumb:hover { border-color: var(--line2); }
.deck-thumb.on { border-color: var(--accent); }