:root{--bg:#f4f7fb;--ink:#142032;--muted:#708097;--line:#e2e8f0;--nav:#07111f;--blue:#1e63ed;--cyan:#14b8d4;--card:#fff;--green:#12a97b;--shadow:0 14px 38px rgba(34,57,89,.09)}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;font-family:"Noto Sans JP",sans-serif;color:var(--ink);background:var(--bg)}button,input{font:inherit}.shell{min-height:100vh}.sidebar{position:fixed;inset:0 auto 0 0;width:248px;padding:28px 20px;background:linear-gradient(180deg,#07111f,#0c1c31);color:#fff;z-index:20;display:flex;flex-direction:column}.brand{display:flex;align-items:center;gap:12px;color:#fff;text-decoration:none;padding:0 8px 28px}.brand-mark{width:42px;height:42px;border-radius:13px;display:grid;place-items:center;font-weight:800;background:linear-gradient(135deg,#1f6df2,#10c9d7);box-shadow:0 8px 24px #1267d866}.brand strong{display:block;font-size:15px}.brand small{font-size:9px;letter-spacing:2px;color:#8ca0bb}.sidebar nav{display:grid;gap:7px}.nav-item{display:flex;align-items:center;gap:13px;padding:12px 14px;border-radius:11px;color:#91a3ba;text-decoration:none;font-size:14px;font-weight:600}.nav-item span{font-size:20px;width:21px;text-align:center}.nav-item:hover,.nav-item.active{color:#fff;background:#ffffff12}.nav-item.active{box-shadow:inset 3px 0 #2e8cff}.sidebar-note{margin-top:auto;border:1px solid #ffffff14;background:#ffffff09;border-radius:14px;padding:14px;display:flex;gap:10px}.sidebar-note strong,.sidebar-note small{display:block}.sidebar-note strong{font-size:12px}.sidebar-note small{font-size:10px;color:#879bb4;margin-top:3px}.pulse{width:9px;height:9px;border-radius:50%;background:#20d6a0;box-shadow:0 0 0 5px #20d6a022;margin-top:4px}.main{margin-left:248px;min-height:100vh}.topbar{height:78px;padding:0 36px;background:#fff;border-bottom:1px solid var(--line);display:flex;align-items:center;gap:24px;position:sticky;top:0;z-index:15}.menu-button{display:none;border:0;background:transparent;font-size:22px}.search{height:44px;max-width:520px;flex:1;display:flex;align-items:center;gap:10px;border:1px solid var(--line);background:#f7f9fc;border-radius:12px;padding:0 14px;color:#8a99ad}.search input{border:0;outline:0;background:transparent;width:100%;font-size:13px}.profile{margin-left:auto;display:flex;gap:10px;align-items:center;border:0;background:transparent;text-align:left;color:var(--ink)}.avatar{width:38px;height:38px;border-radius:50%;display:grid;place-items:center;color:#fff;background:linear-gradient(135deg,#2a70f1,#10b8d3);font-weight:700}.profile-copy strong,.profile-copy small{display:block}.profile-copy strong{font-size:12px}.profile-copy small{font-size:10px;color:var(--muted)}#app{padding:34px 38px 70px;max-width:1500px;margin:auto}.hero{border-radius:24px;min-height:260px;padding:40px 44px;color:#fff;background:radial-gradient(circle at 79% 35%,#20c9e055 0 3%,transparent 4%),radial-gradient(circle at 85% 55%,#0d8ee966 0 8%,transparent 9%),linear-gradient(125deg,#0a1830,#123b7a 62%,#126ba0);position:relative;overflow:hidden;box-shadow:var(--shadow)}.hero:after{content:"AI";position:absolute;right:6%;bottom:-65px;font-size:240px;font-weight:800;color:#ffffff0a;line-height:1}.eyebrow{font-size:11px;letter-spacing:2px;color:#72dced;font-weight:700}.hero h1{font-size:31px;line-height:1.5;margin:10px 0}.hero p{color:#c0d4eb;font-size:13px;line-height:1.8;max-width:570px}.hero-actions{display:flex;gap:12px;margin-top:22px}.button{display:inline-flex;align-items:center;justify-content:center;gap:8px;border:0;border-radius:11px;padding:11px 18px;font-weight:700;font-size:13px;text-decoration:none;cursor:pointer}.button.primary{background:#fff;color:#1559bd}.button.ghost{background:#ffffff12;color:#fff;border:1px solid #ffffff25}.section{margin-top:34px}.section-head{display:flex;justify-content:space-between;align-items:end;margin-bottom:17px}.section-head h2{font-size:20px;margin:0}.section-head p{font-size:12px;color:var(--muted);margin:4px 0 0}.text-link{font-size:12px;font-weight:700;color:var(--blue);text-decoration:none}.course-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}.course-card{background:var(--card);border:1px solid #e4eaf2;border-radius:17px;overflow:hidden;box-shadow:0 7px 22px rgba(40,58,83,.05);transition:.2s}.course-card:hover{transform:translateY(-3px);box-shadow:var(--shadow)}.course-cover{height:130px;padding:18px;display:flex;align-items:flex-end;color:#fff;position:relative;background:linear-gradient(135deg,var(--c1),var(--c2))}.course-cover:before{content:"";position:absolute;width:110px;height:110px;border:1px solid #ffffff2c;border-radius:50%;right:-22px;top:-36px}.course-cover b{font-size:12px;letter-spacing:1px}.course-body{padding:16px}.course-body h3{font-size:14px;line-height:1.6;margin:0 0 9px;min-height:45px}.meta{display:flex;justify-content:space-between;color:var(--muted);font-size:11px}.progress{height:5px;background:#e9edf3;border-radius:99px;overflow:hidden;margin:13px 0 7px}.progress i{display:block;height:100%;background:linear-gradient(90deg,var(--blue),var(--cyan));border-radius:inherit}.course-link{color:inherit;text-decoration:none}.chips{display:flex;gap:8px;overflow:auto;padding-bottom:6px;margin-bottom:20px}.chip{white-space:nowrap;border:1px solid var(--line);background:#fff;color:#55647a;border-radius:99px;padding:8px 13px;font-size:11px;cursor:pointer}.chip.active{background:#142846;color:#fff;border-color:#142846}.page-title h1{font-size:25px;margin:0}.page-title p{color:var(--muted);font-size:12px}.lesson-list{display:grid;gap:10px}.lesson-row{display:grid;grid-template-columns:46px 1fr auto;gap:14px;align-items:center;background:#fff;border:1px solid var(--line);border-radius:13px;padding:12px 14px;text-decoration:none;color:inherit}.lesson-index{width:40px;height:40px;border-radius:11px;background:#eff4fc;display:grid;place-items:center;color:#557096;font-size:12px;font-weight:700}.lesson-row h3{font-size:13px;margin:0 0 4px}.lesson-row p{font-size:10px;color:var(--muted);margin:0}.badge{font-size:10px;padding:5px 8px;border-radius:99px;background:#edf3ff;color:#2862bf}.badge.done{background:#e7f8f2;color:#128363}.lesson-layout{display:grid;grid-template-columns:minmax(0,1fr) 320px;gap:22px}.lesson-main,.lesson-side{background:#fff;border:1px solid var(--line);border-radius:17px;overflow:hidden}.video-wrap{aspect-ratio:16/9;background:#07111f}.video-wrap iframe{display:block;width:100%;height:100%;border:0}.empty-video{height:100%;display:grid;place-items:center;text-align:center;color:#b8c4d3;padding:30px}.lesson-content{padding:24px}.breadcrumb{font-size:11px;color:var(--muted);margin-bottom:11px}.lesson-content h1{font-size:21px;line-height:1.5;margin:0}.lesson-actions{display:flex;gap:9px;margin-top:20px}.lesson-actions .button{background:#eef3fb;color:#34506f}.lesson-actions .button.complete{background:#e7f8f2;color:#128363}.lesson-side{padding:18px;height:max-content}.lesson-side h3{font-size:13px;margin:0 0 13px}.side-lesson{display:flex;gap:10px;padding:10px;border-radius:9px;text-decoration:none;color:inherit;font-size:11px}.side-lesson.active{background:#edf4ff;color:#1559bd}.side-lesson span:first-child{color:#8c9bb0}.external-panel{padding:36px;text-align:center;background:linear-gradient(135deg,#edf5ff,#f1fcfd)}.external-panel h2{font-size:18px}.toast{position:fixed;right:24px;bottom:24px;background:#12243e;color:#fff;padding:12px 18px;border-radius:10px;font-size:12px;opacity:0;transform:translateY(10px);transition:.2s;z-index:50}.toast.show{opacity:1;transform:none}.empty{padding:70px 20px;text-align:center;color:var(--muted)}
@media(max-width:1100px){.course-grid{grid-template-columns:repeat(2,1fr)}.lesson-layout{grid-template-columns:1fr}.lesson-side{display:none}}
@media(max-width:760px){.sidebar{transform:translateX(-100%);transition:.2s}.sidebar.open{transform:none}.main{margin-left:0}.topbar{height:66px;padding:0 16px}.menu-button{display:block}.profile-copy{display:none}#app{padding:20px 15px 50px}.hero{padding:28px 23px;min-height:280px}.hero h1{font-size:24px}.course-grid{grid-template-columns:1fr}.course-cover{height:145px}.lesson-row{grid-template-columns:42px 1fr}.lesson-row .badge{display:none}}

/* YouTube-style video discovery */
.video-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:26px 18px}.video-card{color:inherit;text-decoration:none;min-width:0}.video-thumb{aspect-ratio:16/9;border-radius:14px;overflow:hidden;background:#0b1423;position:relative}.video-thumb img{width:100%;height:100%;object-fit:cover;display:block;transition:.25s}.video-card:hover .video-thumb img{transform:scale(1.035)}.duration{position:absolute;right:7px;bottom:7px;background:#080c13dd;color:#fff;border-radius:5px;padding:3px 6px;font-size:10px;font-weight:700}.video-info{display:grid;grid-template-columns:36px 1fr;gap:10px;padding-top:11px}.channel-avatar{width:36px;height:36px;border-radius:50%;display:grid;place-items:center;color:#fff;background:linear-gradient(135deg,#206fea,#12b8c9);font-size:11px;font-weight:800}.video-copy h3{font-size:13px;line-height:1.55;margin:0 0 5px;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}.video-copy p{font-size:10px;color:var(--muted);margin:0;line-height:1.6}.home-categories{margin-top:22px}.shorts-page{height:calc(100vh - 112px);display:flex;flex-direction:column}.shorts-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:12px}.shorts-head h1{font-size:22px;margin:0}.shorts-head p{font-size:11px;color:var(--muted);margin:4px 0 0}.shorts-feed{flex:1;overflow-y:auto;scroll-snap-type:y mandatory;overscroll-behavior:contain;border-radius:18px;background:#07111f}.short-item{height:100%;min-height:100%;scroll-snap-align:start;scroll-snap-stop:always;display:grid;place-items:center;padding:14px;position:relative}.short-stage{height:100%;max-height:760px;aspect-ratio:9/16;max-width:100%;border-radius:18px;overflow:hidden;background:#000;position:relative;box-shadow:0 18px 55px #0007}.short-stage iframe{width:100%;height:100%;border:0}.short-meta{position:absolute;left:16px;right:58px;bottom:18px;color:#fff;text-shadow:0 2px 7px #000}.short-meta h2{font-size:14px;line-height:1.5;margin:0 0 5px}.short-meta p{font-size:10px;margin:0;color:#d9e2ef}.short-actions{position:absolute;right:10px;bottom:18px;display:grid;gap:11px}.short-actions button,.short-actions a{width:42px;height:42px;border-radius:50%;border:0;background:#ffffff22;color:#fff;display:grid;place-items:center;text-decoration:none;font-size:17px;backdrop-filter:blur(7px)}.swipe-hint{color:#91a4bc;font-size:10px}
@media(max-width:1100px){.video-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:760px){.video-grid{grid-template-columns:1fr;gap:22px}.video-thumb{border-radius:11px}.home-categories{margin-top:12px}.shorts-page{height:calc(100dvh - 106px)}#app:has(.shorts-page){padding:12px 8px}.shorts-feed{border-radius:16px}.short-item{padding:8px}.short-stage{height:100%;max-height:none}.shorts-head{padding:0 6px}.shorts-head .swipe-hint{display:none}}
.short-poster{position:absolute;inset:0;width:100%;height:100%;border:0;background-color:#000;background-size:cover;background-position:center;cursor:pointer;display:grid;place-items:center}.short-poster span{width:68px;height:68px;border-radius:50%;display:grid;place-items:center;background:#ffffffea;color:#142032;font-size:25px;padding-left:4px;box-shadow:0 12px 35px #0006}.short-meta{pointer-events:none}
.thumb-fallback{position:absolute;inset:0;padding:18px;display:flex;flex-direction:column;justify-content:flex-end;color:#fff;background:radial-gradient(circle at 82% 18%,#ffffff30 0 7%,transparent 8%),linear-gradient(135deg,var(--c1),var(--c2))}.thumb-fallback:after{content:"AI";position:absolute;right:12px;top:-17px;font-size:92px;line-height:1;font-weight:900;color:#ffffff12}.thumb-fallback small{font-size:8px;letter-spacing:2px;opacity:.76;margin-bottom:auto}.thumb-fallback b{position:relative;font-size:14px;line-height:1.5;max-width:90%;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}.thumb-fallback em{position:relative;font-style:normal;font-size:9px;opacity:.72;margin-top:4px}.video-thumb img{position:absolute;inset:0;z-index:1}.duration{z-index:2}
.course-cover{padding:0}.course-cover img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;z-index:1}.course-cover-fallback{position:absolute;inset:0;padding:16px;display:flex;flex-direction:column;justify-content:space-between}.course-cover-fallback small{font-size:8px;letter-spacing:2px;opacity:.72}.course-cover-fallback b{font-size:13px;line-height:1.5;max-width:82%}.course-group{position:absolute;left:10px;bottom:10px;z-index:2;color:#fff;background:#07111fcc;border-radius:6px;padding:4px 7px;font-size:9px}.lesson-row{grid-template-columns:112px 1fr auto}.lesson-row-thumb{width:112px;aspect-ratio:16/9;border-radius:9px;overflow:hidden;position:relative;background:#0b1423}.lesson-row-thumb .thumb-fallback{padding:8px}.lesson-row-thumb .thumb-fallback small,.lesson-row-thumb .thumb-fallback em{display:none}.lesson-row-thumb .thumb-fallback b{font-size:8px;line-height:1.35}.lesson-row-thumb .thumb-fallback:after{font-size:45px;right:4px;top:-7px}.lesson-row-thumb img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;z-index:1}@media(max-width:760px){.lesson-row{grid-template-columns:92px 1fr}.lesson-row-thumb{width:92px}.lesson-row .badge{display:none}}
.login-recovery{max-width:480px;margin:70px auto;background:#fff;border:1px solid var(--line);border-radius:20px;box-shadow:var(--shadow);padding:42px 24px}.login-recovery .login-mark{width:58px;height:58px;margin:0 auto 18px;border-radius:17px;display:grid;place-items:center;background:#06c755;color:#fff;font-size:11px;font-weight:800}.login-recovery h2{margin:0 0 8px}.login-recovery p{color:var(--muted);font-size:12px;margin:0 0 22px}.login-recovery .line-login{background:#06c755;color:#fff;min-width:210px}.login-recovery .line-login:disabled{opacity:.65}.login-recovery small{display:block;color:var(--muted);font-size:10px;margin-top:12px}