:root{font-family:Inter,"PingFang SC","Microsoft YaHei",system-ui,sans-serif;color:#142a4a;background:#f4f7fc;font-size:16px;font-synthesis:none}*{box-sizing:border-box}body{margin:0}button,input,select{font:inherit}button{cursor:pointer}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid #f4b64d;outline-offset:3px}a{color:inherit;text-decoration:none}.app-shell{min-height:100vh;display:grid;grid-template-columns:244px minmax(0,1fr)}.sidebar{background:#102b56;color:#fff;min-height:100vh;padding:29px 18px 22px;display:flex;flex-direction:column;position:sticky;top:0;height:100vh}.brand{display:flex;gap:12px;align-items:center;padding:0 13px;font-weight:800;font-size:20px;line-height:1.05;letter-spacing:.02em}.brand small{font-size:13px;font-weight:600;color:#9fc1ed;letter-spacing:.06em}.brand-mark{width:40px;height:40px;background:#fff;color:#102b56;border-radius:12px;display:grid;place-items:center;font-size:25px;font-weight:900;letter-spacing:-.08em}.brand-mark span{color:#f5b84a}.side-label{font-size:12px;letter-spacing:.14em;color:#87a5ce;font-weight:700;padding:47px 20px 14px}.side-nav{display:grid;gap:5px}.nav-item{border:0;background:transparent;color:#b8cae5;display:flex;gap:14px;align-items:center;text-align:left;padding:13px 16px;border-radius:11px;font-size:15px;font-weight:650;width:100%}.nav-item:hover,.nav-item.active{background:#244772;color:#fff}.nav-item.active{box-shadow:inset 3px 0 #f5bd55}.nav-icon{width:20px;text-align:center;font-size:22px;line-height:1;font-weight:500}.sidebar-foot{margin-top:auto;border-top:1px solid #345278;padding:21px 12px 0;color:#c6d8f2;font-weight:650;font-size:14px}.sidebar-foot small{display:block;margin:8px 0 0 17px;color:#87a5ce;font-weight:400;font-size:12px}.foot-dot{display:inline-block;width:8px;height:8px;border-radius:50%;background:#f5bd55;margin-right:8px}.main-wrap{min-width:0}.topbar{height:76px;background:#fff;border-bottom:1px solid #e1e8f2;display:flex;align-items:center;justify-content:space-between;padding:0 clamp(20px,4.2vw,64px);gap:20px}.breadcrumb{color:#70829e;font-size:14px}.breadcrumb span{margin:0 11px;color:#b3c0d0}.breadcrumb strong{color:#1e365b}.top-actions{display:flex;align-items:center;gap:20px}.top-badge{color:#315989;background:#eef5ff;border-radius:40px;padding:7px 12px;font-size:13px;font-weight:750}.account-button{border:1px solid #d6e2f0;background:#fff;color:#193a66;border-radius:9px;padding:9px 16px;font-size:14px;font-weight:700}.account-button:hover{background:#f1f6fc}.content{max-width:1380px;margin:0 auto;padding:44px clamp(20px,4.2vw,64px) 70px}.view{display:none}.view.active{display:block}.page-heading{display:flex;align-items:end;justify-content:space-between;gap:24px;margin-bottom:28px}.eyebrow,.panel-kicker{font-size:12px;font-weight:800;letter-spacing:.14em;color:#2778bd;text-transform:uppercase;margin:0 0 11px}h1{font-size:clamp(29px,3vw,42px);line-height:1.2;letter-spacing:-.035em;margin:0 0 10px;color:#102b56}h2{font-size:21px;line-height:1.3;margin:0;color:#17345c}.subhead{margin:0;color:#71839d;font-size:15px;line-height:1.7}.heading-decoration{font-size:15px;font-weight:800;letter-spacing:.25em;color:#a8c1e0;padding-bottom:8px}.level-grid{display:grid;grid-template-columns:repeat(8,minmax(0,1fr));gap:11px;margin-bottom:28px}.level-button{border:1px solid #d9e3ef;background:#fff;border-radius:13px;min-height:110px;padding:15px 10px;text-align:left;display:flex;flex-direction:column;justify-content:space-between;transition:transform .15s,border-color .15s,box-shadow .15s}.level-button:hover{transform:translateY(-2px);border-color:#83b8e9;box-shadow:0 8px 22px #d5e3f580}.level-button.selected{background:#1261a2;border-color:#1261a2;color:#fff;box-shadow:0 8px 21px #1261a22e}.level-button .level-number{font-size:28px;font-weight:850;letter-spacing:-.05em;line-height:1}.level-button .level-caption{font-size:12px;font-weight:650;color:#7185a1}.level-button.selected .level-caption{color:#d4eaff}.dashboard-grid{display:grid;grid-template-columns:minmax(0,1.6fr) minmax(285px,1fr);gap:20px}.panel{background:#fff;border:1px solid #e0e8f1;border-radius:18px;padding:26px;box-shadow:0 4px 18px #102b5608}.panel-head{display:flex;align-items:start;justify-content:space-between;gap:20px;margin-bottom:18px}.text-link{border:0;background:transparent;color:#136bac;font-size:14px;font-weight:750;white-space:nowrap;padding:4px 0}.text-link:hover{text-decoration:underline}.paper-list{display:grid}.paper-row{display:flex;align-items:center;justify-content:space-between;gap:20px;border-top:1px solid #edf1f6;padding:18px 0}.paper-row:first-child{border-top:0}.paper-row strong{font-size:16px;color:#203b61}.paper-row small{display:block;color:#8090a8;margin-top:6px;font-size:12px}.paper-state{font-size:12px;font-weight:700;color:#9b6b20;background:#fff6e6;border-radius:20px;padding:7px 10px;white-space:nowrap}.quick-panel{background:linear-gradient(145deg,#e8f3ff 0%,#f9fcff 78%);border-color:#c9def5}.quick-panel h2{font-size:24px}.quick-panel>p:not(.panel-kicker):not(.demo-note){color:#5c7694;line-height:1.7;margin:13px 0 20px}.quick-code{background:#102b56;color:#d7ecff;border-radius:11px;padding:18px 19px;font:15px/1.8 Consolas,"Courier New",monospace;margin-bottom:20px}.primary-button{border:0;background:#f4b74f;color:#26334a;border-radius:10px;padding:12px 18px;font-weight:800;font-size:15px;display:inline-flex;gap:20px;align-items:center;justify-content:space-between;box-shadow:0 5px 12px #e8a93d30}.primary-button:hover{background:#ffc86a}.demo-note{font-size:12px!important;line-height:1.5!important;color:#8293aa!important;margin:15px 0 0!important}.mobile-menu{display:none}.toast{position:fixed;bottom:22px;right:22px;background:#193a66;color:#fff;padding:12px 18px;border-radius:10px;box-shadow:0 10px 28px #102b5633;opacity:0;pointer-events:none;transform:translateY(10px);transition:.2s;z-index:20}.toast.show{opacity:1;transform:none}@media(max-width:1080px){.level-grid{grid-template-columns:repeat(4,1fr)}.dashboard-grid{grid-template-columns:1fr}}@media(max-width:720px){.app-shell{display:block}.sidebar{position:fixed;z-index:30;inset:0 auto 0 0;width:244px;transform:translateX(-100%);transition:transform .2s}.sidebar.open{transform:translateX(0)}.topbar{height:64px;padding:0 18px}.mobile-menu{display:inline-flex;border:0;background:transparent;color:#183a66;font-size:23px;padding:3px}.breadcrumb{margin-right:auto}.top-badge{display:none}.account-button{padding:8px 10px;font-size:13px}.content{padding:28px 18px 50px}.heading-decoration{display:none}.level-grid{grid-template-columns:repeat(4,1fr);gap:8px}.level-button{min-height:84px;padding:11px}.level-button .level-number{font-size:23px}.panel{padding:21px}.page-heading{margin-bottom:22px}}
:root{--practice-blue:#1261a2}.demo-question{max-width:820px}.question-meta{color:#5b83aa;font-size:13px;font-weight:800;margin-bottom:18px}.demo-question h2{font-size:22px;line-height:1.6}.question-code{background:#102b56;color:#e6f3ff;padding:20px;border-radius:11px;overflow:auto;font:15px/1.7 Consolas,"Courier New",monospace}.option-list{display:grid;gap:10px;margin-top:19px}.answer-option{display:flex;align-items:center;gap:14px;text-align:left;background:#fff;border:1px solid #dce6f1;border-radius:10px;padding:13px 15px;color:#1c3659}.answer-option:hover:not(:disabled){border-color:#1261a2;background:#f4f9ff}.answer-option b{width:28px;height:28px;border-radius:7px;background:#edf4fb;color:#1f5f9d;display:grid;place-items:center}.answer-option.correct{border-color:#3aa976;background:#f0faf5}.answer-option.incorrect{border-color:#e3907b;background:#fff4f1}.feedback{margin-top:18px;border-left:4px solid #2d8dc3;background:#edf7ff;border-radius:8px;padding:16px 18px;line-height:1.7}.feedback p{margin:7px 0 0}
.heading-action{flex-shrink:0}.paper-panel{min-width:0}
.paper-toolbar{display:flex;align-items:end;justify-content:space-between;gap:20px;margin-bottom:20px}.field-label{display:block;color:#647e9b;font-size:13px;font-weight:750;margin-bottom:7px}.field-select,.timer-form input{border:1px solid #cfdbeb;border-radius:10px;background:#fff;color:#17345c;padding:10px 14px;min-height:44px}.field-select{min-width:150px}.paper-count{font-size:14px;color:#7387a2;padding-bottom:11px}.paper-card-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}.paper-card{background:#fff;border:1px solid #e0e8f1;border-radius:15px;padding:21px;min-width:0}.paper-card-top,.paper-card-bottom{display:flex;align-items:center;justify-content:space-between}.paper-card-icon{font-size:26px;color:#2676b5}.paper-card h2{font-size:19px;margin:22px 0 8px}.paper-card p{color:#788ba3;font-size:13px;line-height:1.6;margin:0 0 19px}.paper-card-bottom{border-top:1px solid #edf1f6;padding-top:15px;color:#8191a7;font-size:12px;font-weight:650}.paper-card-bottom span:last-child{font-size:17px}.demo-banner{display:flex;align-items:end;justify-content:space-between;gap:25px;background:#e7f2ff;border:1px solid #c7dff7;border-radius:17px;padding:25px;margin-top:25px}.demo-banner p:not(.panel-kicker){margin:10px 0 0;color:#627d9b;font-size:14px;line-height:1.6}.timer-form{display:flex;align-items:end;gap:10px;flex-shrink:0}.timer-form label{font-size:13px;font-weight:750;color:#375e87;align-self:center}.timer-form input{width:82px}.action-panel{max-width:770px}.action-panel-main{display:flex;align-items:center;gap:20px}.round-symbol{width:66px;height:66px;border-radius:17px;background:#e7f2ff;display:grid;place-items:center;color:#1b6eaa;font-size:35px;flex-shrink:0}.action-panel-main p{color:#71839d;line-height:1.65;margin:9px 0 0}.action-panel-foot{border-top:1px solid #e6edf5;margin-top:28px;padding-top:22px;display:flex;align-items:center;justify-content:space-between;gap:15px;color:#7587a0;font-size:14px}.notice-card{margin-top:17px;padding:14px 17px;border-radius:10px;background:#fff7e9;color:#8b671e;border:1px solid #f8e8c7;font-size:13px;line-height:1.6;max-width:770px}.practice-layout{display:grid;grid-template-columns:minmax(0,1fr) 255px;gap:18px;align-items:start}.question-panel{padding:29px}.practice-topline{display:flex;justify-content:space-between;align-items:start;gap:16px;margin-bottom:22px}.practice-topline>div:first-child{width:45%;max-width:300px}.practice-progress{display:block;background:#eaf0f6;height:5px;border-radius:5px;overflow:hidden;margin-top:12px}.practice-progress span{display:block;background:#1e78bc;height:100%}.question-actions{display:flex;align-items:center;gap:9px}.timer-pill{font:700 14px Consolas,monospace;padding:9px 12px;background:#e8f3ff;color:#1d64a3;border-radius:9px}.timer-pill.urgent{background:#fff0e9;color:#c65a3f}.favorite-button{border:1px solid #dce6f1;color:#6c819a;background:#fff;border-radius:9px;padding:8px 11px;font-size:13px;font-weight:700}.favorite-button.on{background:#fff6e6;border-color:#f3d69c;color:#9d6c13}.question-panel h2{font-size:21px;line-height:1.65;margin:0 0 16px}.question-panel .option-list{margin-top:20px}.answer-option.selected{border-color:#1b75b9;background:#eaf5ff;box-shadow:inset 3px 0 #1b75b9}.answer-option:disabled{cursor:default}.feedback.is-correct{background:#f0faf5;border-color:#31a476}.feedback.is-wrong{background:#fff5f1;border-color:#db8069}.question-footer{display:flex;align-items:center;justify-content:space-between;gap:14px;margin-top:24px;padding-top:20px;border-top:1px solid #e9eef5;color:#8393a8;font-size:13px}.primary-button:disabled{opacity:.5;cursor:not-allowed;box-shadow:none}.side-guide strong{display:block;font-size:31px;color:#164f86;margin-top:6px}.side-guide>span{color:#7b8da4;font-size:13px}.side-marks{display:grid;grid-template-columns:repeat(5,1fr);gap:7px;margin:23px 0}.side-marks span{height:32px;border-radius:8px;background:#edf2f8;color:#8493a7;display:grid;place-items:center;font-size:13px;font-weight:750}.side-marks .current{background:#e0f0ff;color:#1b6da9;box-shadow:inset 0 0 0 1px #a8d2f2}.side-marks .right{background:#dff5e9;color:#268357}.side-marks .wrong{background:#fff0e9;color:#bc6752}.side-guide small{font-size:12px;color:#91a0b4}.result-panel{max-width:770px;text-align:center;padding:42px}.result-score strong{display:block;font-size:72px;color:#155e9b;letter-spacing:-.06em;line-height:1}.result-score small{font-size:35px;color:#99b0c7}.result-score>span{display:block;color:#768aa5;margin-top:10px}.result-details{display:grid;grid-template-columns:repeat(3,1fr);border-top:1px solid #e9eff6;border-bottom:1px solid #e9eff6;margin:30px 0;padding:23px 0}.result-details>div{display:grid;gap:6px}.result-details b{font-size:24px;color:#193f6a}.result-details span{font-size:13px;color:#8798ad}.result-actions{display:flex;justify-content:center;gap:10px}.secondary-button{border:1px solid #cbd9e8;background:#fff;color:#225689;border-radius:10px;padding:11px 17px;font-weight:750}.secondary-button:hover{background:#f3f8fc}.collection-head{display:flex;align-items:center;justify-content:space-between;gap:14px;margin-bottom:18px;color:#71859d;font-size:14px}.collection-list{display:grid;gap:10px}.collection-row{display:flex;align-items:center;gap:19px;background:#fff;border:1px solid #e1e9f2;border-radius:13px;padding:19px 21px}.collection-number{font-size:22px;font-weight:850;color:#b1c8df}.collection-row div{flex:1;min-width:0}.collection-row strong{display:block;color:#203c61;line-height:1.5}.collection-row small{display:block;color:#8697aa;margin-top:5px}.collection-arrow{color:#80a6c9}.empty-state{max-width:640px;text-align:center;padding:45px 24px}.empty-icon{font-size:45px;color:#8ab7dc}.empty-state h2{margin:10px 0}.empty-state p{color:#8191a6;margin:10px 0 22px}.stats-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin-bottom:20px}.stat-card{background:#fff;border:1px solid #e0e8f1;border-radius:15px;padding:22px}.stat-card span,.stat-card small{display:block;color:#8192a9;font-size:13px}.stat-card strong{display:block;font-size:37px;color:#155b97;letter-spacing:-.05em;margin:12px 0 8px}.stat-card em{font-size:21px;font-style:normal}.stats-detail{max-width:800px}.stats-percent{font-size:24px;font-weight:800;color:#1c649e}.stat-track{background:#eaf1f8;height:10px;border-radius:10px;overflow:hidden}.stat-track span{display:block;height:100%;background:#2587c4;border-radius:10px}.stats-detail>p{color:#8293a8;font-size:13px;line-height:1.7;margin:15px 0 0}.account-dialog{border:0;border-radius:18px;box-shadow:0 20px 70px #071e4490;width:min(440px,calc(100% - 36px));padding:28px;color:#15345b}.account-dialog::backdrop{background:#0a254dc0}.dialog-top{display:flex;justify-content:space-between;align-items:center;margin-bottom:25px}.icon-button{border:0;background:transparent;color:#657d98;font-size:25px;line-height:1}.account-dialog h2{font-size:24px}.account-dialog p{line-height:1.7;color:#6c809a}.account-dialog .notice-card{margin:20px 0}.account-dialog .primary-button{width:100%;justify-content:center}@media(max-width:1100px){.paper-card-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.practice-layout{grid-template-columns:1fr}.practice-side{display:none}.stats-grid{grid-template-columns:repeat(2,1fr)}}@media(max-width:720px){.paper-card-grid{grid-template-columns:1fr}.paper-toolbar{align-items:start;flex-direction:column}.demo-banner{flex-direction:column;align-items:stretch}.timer-form{flex-wrap:wrap}.timer-form label{width:100%}.timer-form .primary-button{flex:1}.practice-topline{align-items:start;flex-direction:column}.practice-topline>div:first-child{width:100%}.question-actions{width:100%;justify-content:space-between}.question-panel{padding:21px}.question-footer{align-items:stretch;flex-direction:column}.question-footer .primary-button{justify-content:center}.stats-grid{gap:9px}.stat-card{padding:16px}.stat-card strong{font-size:30px}.result-details b{font-size:19px}.result-actions{flex-direction:column}}

.brand-avatar{width:40px;height:40px;border-radius:12px;object-fit:cover;object-position:center;display:block;flex:none}
.paper-start-form{display:flex;align-items:end;gap:9px;flex-wrap:wrap;border-top:1px solid #edf1f6;padding-top:14px}.paper-start-form label{font-size:12px;font-weight:700;color:#647e9b;display:grid;gap:5px}.paper-start-form input{width:76px;min-height:42px;border:1px solid #cfdbeb;border-radius:9px;padding:8px;color:#17345c}.paper-start-form .primary-button{min-height:42px;padding:9px 13px;font-size:13px}.paper-caveat{display:block;margin-top:10px;color:#8b671e;font-size:11px;line-height:1.5}

.answer-option.has-code{align-items:flex-start;text-align:left;gap:16px}
.answer-option.has-code b{flex:0 0 28px;margin-top:2px}
.option-code{flex:1;min-width:0;max-width:100%;margin:0;overflow-x:auto;white-space:pre;tab-size:4;font:15px/1.55 Consolas,"Cascadia Code","Courier New",monospace;color:inherit}
.option-code code{font:inherit}
.question-figure{margin:18px 0 20px;padding:14px;border:1px solid #dce6f1;border-radius:11px;background:#fff;text-align:center;overflow:auto}
.question-figure img{display:block;max-width:100%;height:auto;margin:0 auto}
@media(max-width:640px){.answer-option.has-code{gap:10px}.option-code{font-size:13px}}

.account-button.is-signed-in{background:#e8f4ff;color:#155f9c;border-color:#bcdaf2}
.account-dialog{width:min(480px,calc(100% - 32px));padding:28px 30px}
.dialog-brand{display:flex;align-items:center;gap:11px;font-weight:800;color:#173e69}
.main-wrap{display:flex;flex-direction:column;min-height:100vh}.content{width:100%;flex:1}.site-footer{display:flex;justify-content:center;gap:14px;flex-wrap:wrap;border-top:1px solid #e1e8f2;padding:20px clamp(20px,4.2vw,64px);color:#71839d;font-size:13px;text-align:center}.site-footer a{color:inherit;text-decoration:none}.site-footer a:hover{text-decoration:underline}
.auth-tabs{display:grid;grid-template-columns:1fr 1fr;gap:6px;background:#eef4fa;border-radius:11px;padding:4px;margin-bottom:24px}
.auth-tab{border:0;border-radius:8px;background:transparent;color:#71849d;font-weight:750;padding:10px;cursor:pointer}
.auth-tab.active{background:#fff;color:#155f9d;box-shadow:0 2px 8px #183c6814}
.auth-form{display:grid;gap:15px;margin-top:20px}
.auth-field{display:grid;gap:7px;color:#355879;font-size:13px;font-weight:750}
.auth-field input{width:100%;box-sizing:border-box;border:1px solid #ccdbea;border-radius:10px;background:#fff;color:#17345c;padding:12px 13px;font:inherit;outline:none}
.auth-field input:focus{border-color:#2582bd;box-shadow:0 0 0 3px #dcefff}
.auth-message{border-radius:9px;background:#edf8f3;color:#267652;padding:11px 13px;font-size:13px;line-height:1.55}
.auth-message.is-error{background:#fff2ef;color:#b4513b}
.auth-link{border:0;background:transparent;color:#216fa9;font-weight:700;padding:10px 0;margin-top:8px;cursor:pointer}
.auth-back{margin:-8px 0 12px;text-align:left}
.auth-footnote{font-size:12px!important;margin:13px 0 0!important;color:#8293a7!important}
.account-summary{background:#f3f8fd;border:1px solid #dce8f3;border-radius:13px;padding:18px;margin:20px 0}
.account-summary strong{display:block;margin:13px 0 5px;color:#173e69;word-break:break-all}
.account-summary p{font-size:13px;margin:0}
.account-status{display:flex;align-items:center;gap:7px;color:#2f7b5c;font-size:13px;font-weight:750}
.account-status i{width:8px;height:8px;border-radius:50%;background:#38a979;box-shadow:0 0 0 4px #dff4e9}
.sign-out-button{width:100%}
.account-dialog button:disabled,.account-dialog input:disabled{opacity:.6;cursor:wait}
@media(max-width:520px){.account-dialog{padding:22px}.dialog-brand span{font-size:14px}}