:root{--ink:#111318;--muted:#6d6f6a;--paper:#f7f5ef;--line:#deddd7;--orange:#ff500d;--blue:#155eef;--green:#20a66a;--yellow:#ffda17;--soft-blue:#eef4ff;--soft-orange:#fff1e9;--white:#fff;--shadow:0 18px 60px rgba(17,19,24,.09);font-family:"PingFang SC","Microsoft YaHei","Noto Sans CJK SC",Arial,sans-serif;color:var(--ink);background:var(--paper)}
*{box-sizing:border-box}html,body{margin:0;min-height:100%;background:var(--paper)}button,input,select{font:inherit}button,a{touch-action:manipulation}.eyebrow{margin:0 0 18px;color:var(--blue);font-size:13px;font-weight:900;letter-spacing:.19em}.login-view{min-height:100vh;display:grid;grid-template-columns:minmax(0,1.16fr) minmax(460px,.84fr);padding:clamp(28px,5vw,84px);gap:clamp(40px,8vw,140px);align-items:center;overflow:hidden;position:relative}.login-view:before{content:"";position:absolute;inset:0;background:linear-gradient(90deg,transparent 0 61%,rgba(255,255,255,.58) 61%),linear-gradient(rgba(21,94,239,.035) 1px,transparent 1px),linear-gradient(90deg,rgba(21,94,239,.035) 1px,transparent 1px);background-size:auto,36px 36px,36px 36px;pointer-events:none}.login-copy,.login-card{position:relative;z-index:1}.brand-mark{font:900 46px/1 Arial;color:var(--orange);margin-bottom:clamp(54px,8vh,110px)}.login-copy h1{font-size:clamp(48px,5.2vw,86px);line-height:1.05;letter-spacing:-.055em;margin:0;max-width:900px}.login-lead{max-width:690px;color:#4f514d;font-size:clamp(16px,1.35vw,22px);line-height:1.8;margin:34px 0}.feature-row{display:flex;flex-wrap:wrap;gap:10px}.feature-row span{border:1px solid var(--line);background:rgba(255,255,255,.7);padding:11px 16px;font-size:13px;font-weight:800}.login-card{width:min(100%,600px);justify-self:end;background:rgba(255,255,255,.94);border:1px solid var(--line);padding:clamp(30px,4vw,66px);box-shadow:var(--shadow)}.login-card-head h2,dialog h2{font-size:clamp(34px,3vw,54px);letter-spacing:-.045em;margin:0 0 12px}.login-card-head>p:last-child,dialog form>p{color:var(--muted);margin:0 0 34px;line-height:1.65}.field{display:grid;gap:9px;margin:0 0 22px}.field>span:first-child{font-weight:900;font-size:14px}.field input,.field select{width:100%;height:56px;border:1px solid var(--line);background:#fff;padding:0 16px;color:var(--ink);outline:none}.field input:focus,.field select:focus,.input-shell:focus-within{border-color:var(--blue);box-shadow:0 0 0 3px rgba(21,94,239,.1)}.input-shell{height:58px;display:grid;grid-template-columns:62px 1fr auto;border:1px solid var(--line);background:#fff}.input-shell b{display:grid;place-items:center;background:var(--soft-blue);color:var(--blue);font-size:13px}.input-shell input{height:56px;border:0;box-shadow:none!important}.text-button{border:0;background:transparent;color:var(--blue);font-weight:800;padding:0 18px;cursor:pointer}.primary-button{height:64px;width:100%;border:0;background:var(--orange);color:#fff;display:flex;align-items:center;justify-content:space-between;padding:0 24px;font-size:19px;font-weight:900;box-shadow:8px 9px 0 #ffe3d7;cursor:pointer}.primary-button:hover{filter:brightness(.97);transform:translateY(-1px)}.primary-button:disabled{opacity:.55;cursor:wait}.primary-button.compact{height:54px;font-size:15px;box-shadow:none}.form-message{min-height:22px;color:#c83d13;font-size:13px;margin:-8px 0 16px}.cloud-note{display:flex;align-items:center;gap:9px;margin:30px 0 0;padding-top:20px;border-top:1px solid var(--line);font-size:13px;font-weight:800;color:#52544f}.cloud-note i,.sync-status i{width:8px;height:8px;border-radius:50%;background:var(--green);box-shadow:0 0 0 4px rgba(32,166,106,.12)}.cloud-note[data-state=error] i,.sync-status[data-state=error] i{background:#d53f2c;box-shadow:0 0 0 4px rgba(213,63,44,.12)}.support-note{font-size:12px;color:#8a8b87;margin:15px 0 0}.classroom{height:100vh;min-height:0;display:grid;grid-template-rows:58px minmax(0,1fr);background:#fff}.cloud-bar{display:flex;align-items:center;justify-content:space-between;gap:18px;padding:0 24px;border-bottom:1px solid var(--line);background:#fbfaf6;z-index:10}.cloud-brand{display:flex;align-items:center;gap:12px;color:var(--ink);text-decoration:none;font-size:13px;font-weight:900}.cloud-brand b{font:900 27px/1 Arial;color:var(--orange)}.cloud-session{display:flex;align-items:center;gap:10px}.sync-status{display:flex;align-items:center;gap:8px;font-size:12px;font-weight:800;color:#4f514d;margin-right:6px}.sync-status[data-state=syncing] i{background:var(--blue);animation:pulse 1s infinite}.account-name{font-size:12px;font-weight:900;padding-right:8px}.outline-button{height:36px;padding:0 14px;display:inline-grid;place-items:center;border:1px solid var(--line);background:#fff;color:var(--ink);font-size:12px;font-weight:800;text-decoration:none;cursor:pointer}.outline-button:hover{border-color:var(--blue);color:var(--blue)}.course-stage{min-height:0;position:relative;overflow:hidden}.course-stage iframe{display:block;width:100%;height:100%;border:0;background:#f7f5ef}.course-loading,.cloud-blocker{position:absolute;inset:0;z-index:3;display:grid;place-items:center;text-align:center;background:var(--paper)}.course-loading b{display:block;margin:18px 0 6px}.course-loading small{color:var(--muted)}.spinner{width:42px;height:42px;border:4px solid #dfe6f5;border-top-color:var(--blue);border-radius:50%;animation:spin .8s linear infinite}.cloud-blocker{background:rgba(247,245,239,.96)}.cloud-blocker>div{width:min(92%,520px);border:1px solid var(--line);background:#fff;padding:42px;box-shadow:var(--shadow)}.cloud-blocker h2{font-size:34px;margin:0 0 12px}.cloud-blocker p:not(.eyebrow){line-height:1.7;color:var(--muted);margin:0 0 24px}dialog{border:1px solid var(--line);padding:0;width:min(92vw,520px);box-shadow:var(--shadow)}dialog::backdrop{background:rgba(17,19,24,.42)}dialog form{padding:38px;position:relative}.dialog-close{position:absolute;right:18px;top:15px;border:0;background:transparent;font-size:28px;cursor:pointer}.dialog-close:hover{color:var(--orange)}[hidden]{display:none!important}@keyframes spin{to{transform:rotate(1turn)}}@keyframes pulse{50%{opacity:.35}}
@media(max-width:900px){.login-view{grid-template-columns:1fr;padding:24px;gap:42px;align-content:start}.login-view:before{background:linear-gradient(rgba(21,94,239,.035) 1px,transparent 1px),linear-gradient(90deg,rgba(21,94,239,.035) 1px,transparent 1px);background-size:30px 30px}.brand-mark{margin-bottom:48px}.login-copy h1{font-size:clamp(42px,11vw,66px)}.login-lead{font-size:16px}.login-card{justify-self:stretch;width:100%;padding:30px}.cloud-bar{padding:0 12px}.cloud-brand span,.account-name,.sync-status span{display:none}.cloud-session{gap:6px}.outline-button{padding:0 10px}.classroom{grid-template-rows:52px minmax(0,1fr)}}
@media(max-width:520px){.login-copy{padding-top:4px}.brand-mark{font-size:35px;margin-bottom:32px}.login-copy h1{font-size:42px}.login-lead{margin:22px 0;line-height:1.65}.login-card{padding:24px 20px}.login-card-head h2{font-size:36px}.feature-row span{font-size:11px;padding:9px 11px}.field{margin-bottom:17px}.primary-button{height:58px}.cloud-bar{overflow-x:auto}.cloud-brand{flex:0 0 auto}.cloud-session{flex:0 0 auto}.outline-button{height:34px;font-size:11px}.cloud-blocker>div{padding:28px 22px}}