*,:before,:after{box-sizing:border-box;margin:0;padding:0}:root{--bg:#0a0a0a;--sidebar-bg:#111;--surface:#1a1a1a;--surface2:#222;--border:#282828;--text:#f0f0f0;--muted:#666;--faint:#333}html,body,#root{background:var(--bg);height:100%;color:var(--text);-webkit-font-smoothing:antialiased;-webkit-tap-highlight-color:transparent;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif}button{cursor:pointer;font:inherit;color:inherit;background:0 0;border:none}a{color:inherit;text-decoration:none}.app-header{border-bottom:1px solid var(--border);background:var(--sidebar-bg);z-index:20;flex-shrink:0;align-items:center;gap:12px;height:52px;padding:0 20px;display:flex}.app-header .logo{background:linear-gradient(135deg,#a78bfa,#60a5fa);-webkit-text-fill-color:transparent;-webkit-background-clip:text;font-size:17px;font-weight:800}.app-header .sub{color:var(--muted);font-size:13px;font-weight:400}.app-header .back-btn{color:var(--muted);padding:6px 10px 6px 4px;font-size:14px;display:none}.app-body{flex:1;height:calc(100dvh - 52px);display:flex;overflow:hidden}.sidebar{background:var(--sidebar-bg);border-right:1px solid var(--border);flex-direction:column;flex-shrink:0;width:100%;display:flex;overflow:hidden}.day-tabs{border-bottom:1px solid var(--border);flex-shrink:0;gap:6px;padding:12px 12px 0;display:flex}.day-tab{color:var(--muted);text-align:center;background:0 0;border-bottom:2px solid #0000;border-radius:10px 10px 0 0;flex:1;padding:9px 4px;font-size:13px;font-weight:700;transition:all .2s}.day-tab.active{color:var(--text);border-bottom-color:var(--active-color,#6366f1)}.day-info{border-bottom:1px solid var(--border);flex-shrink:0;padding:14px 16px 10px}.day-info .day-label{letter-spacing:.12em;text-transform:uppercase;margin-bottom:4px;font-size:11px;font-weight:700}.day-info .day-focus{color:var(--text);font-size:14px;font-weight:600}.day-info .day-count{color:var(--muted);margin-top:2px;font-size:12px}.exercise-list{flex:1;padding:8px 0;overflow-y:auto}.exercise-item{text-align:left;border-left:3px solid #0000;align-items:center;gap:12px;width:100%;padding:12px 16px;transition:background .15s;display:flex}.exercise-item:hover{background:var(--surface)}.exercise-item.active{background:var(--surface);border-left-color:var(--active-color,#6366f1)}.ex-num{background:var(--surface2);width:28px;height:28px;color:var(--muted);border-radius:8px;flex-shrink:0;justify-content:center;align-items:center;font-size:12px;font-weight:700;transition:all .2s;display:flex}.exercise-item.active .ex-num{background:color-mix(in srgb, var(--active-color,#6366f1) 20%, transparent);color:var(--active-color,#6366f1)}.ex-name{color:var(--muted);flex:1;font-size:13.5px;font-weight:500;line-height:1.3;transition:color .2s}.exercise-item.active .ex-name,.exercise-item:hover .ex-name{color:var(--text)}.ex-arrow{color:var(--faint);flex-shrink:0;font-size:12px}.exercise-item.active .ex-arrow{color:var(--active-color,#6366f1)}.stretching-link{border-top:1px solid var(--border);color:var(--muted);flex-shrink:0;align-items:center;gap:10px;padding:12px 16px;font-size:13px;transition:color .15s;display:flex}.stretching-link:hover{color:var(--text);background:var(--surface)}.main-panel{background:var(--bg);flex-direction:column;flex:1;display:flex;overflow-y:auto}.video-area{flex-direction:column;flex:1;gap:24px;width:100%;max-width:960px;margin:0 auto;padding:32px 40px;display:flex}.exercise-title{color:var(--text);font-size:24px;font-weight:800;line-height:1.2}.exercise-meta{color:var(--muted);margin-top:6px;font-size:14px}.video-wrapper{background:#000;border-radius:14px;width:100%;padding-top:56.25%;position:relative;overflow:hidden;box-shadow:0 24px 80px #0009}.video-wrapper iframe,.video-wrapper .rp-wrapper{position:absolute;inset:0;width:100%!important;height:100%!important}.video-wrapper>div{inset:0;position:absolute!important}.thumb-fallback{cursor:pointer;flex-direction:column;justify-content:center;align-items:center;gap:16px;text-decoration:none;display:flex;position:absolute;inset:0}.thumb-fallback img{object-fit:cover;width:100%;height:100%;position:absolute;inset:0}.thumb-overlay{background:#00000059;position:absolute;inset:0}.play-circle{z-index:2;color:#fff;border-radius:50%;justify-content:center;align-items:center;width:72px;height:72px;font-size:28px;display:flex;position:relative;box-shadow:0 8px 32px #00000080}.yt-badge{z-index:2;color:#ddd;background:#000000bf;border-radius:6px;align-items:center;gap:5px;padding:5px 10px;font-size:12px;display:flex;position:absolute;bottom:14px;right:16px}.nav-hint{justify-content:space-between;gap:10px;display:flex}.nav-btn{background:var(--surface);border:1px solid var(--border);color:var(--muted);border-radius:10px;flex:1;align-items:center;gap:8px;padding:12px 14px;font-size:13px;transition:all .15s;display:flex}.nav-btn:hover{color:var(--text);border-color:var(--faint)}.nav-btn.next{text-align:right;justify-content:flex-end}.nav-btn-label{color:var(--muted);font-size:11px}.nav-btn-name{color:var(--text);font-size:13px;font-weight:600}.welcome{color:var(--muted);text-align:center;flex-direction:column;flex:1;justify-content:center;align-items:center;gap:12px;padding:40px;font-size:15px;display:flex}.welcome .icon{font-size:48px}.welcome h2{color:var(--text);font-size:20px;font-weight:700}@media (width>=768px){#root{flex-direction:column;max-width:none;display:flex}.sidebar{width:300px}.app-header .back-btn{display:none!important}.main-panel{display:flex!important}}@media (width<=767px){.app-header .back-btn.visible{align-items:center;gap:4px;display:flex}.sidebar.hidden-mobile,.main-panel.hidden-mobile{display:none}.video-area{padding:20px 16px 32px}.exercise-title{font-size:19px}}@keyframes spin{to{transform:rotate(360deg)}}::-webkit-scrollbar{width:4px}::-webkit-scrollbar-track{background:0 0}::-webkit-scrollbar-thumb{background:var(--border);border-radius:4px}