:root{--bg:#050b18;--panel:rgba(7,25,52,.92);--line:#168bd4;--cyan:#6cecff;--gold:#ffd56a;--muted:#9db4ce;--danger:#ff7588}*{box-sizing:border-box}body{margin:0;min-width:1100px;background:radial-gradient(circle at 50% 0,#123b68 0,#050b18 48%,#02040b 100%);color:#eef8ff;font:16px "Microsoft YaHei",sans-serif}button,input,select,textarea{font:inherit}button{cursor:pointer;border:1px solid #269bd8;background:linear-gradient(#17649a,#0b2f5c);color:#fff;padding:12px 18px;min-height:44px;border-radius:8px;box-shadow:0 0 16px #079fe933}button:hover{filter:brightness(1.25);transform:translateY(-1px)}button.secondary{background:#122541;border-color:#43617e}button.danger{border-color:#b8546d;background:#481c3a}.shell{min-height:100vh;padding:26px 38px;background:url('assets/ui/frame.png') center/100% 100% no-repeat}.topbar{display:flex;justify-content:space-between;align-items:center;gap:20px;margin:12px auto 28px;max-width:1280px}.brand{font-size:30px;font-weight:800;letter-spacing:3px;color:var(--cyan);text-shadow:0 0 18px #00cfff}.subtitle{color:var(--muted);font-size:13px;letter-spacing:2px}.nav{display:flex;gap:8px;flex-wrap:wrap}.nav button{padding:8px 12px;min-height:38px}.content{max-width:1280px;margin:auto}.panel{background:var(--panel);border:1px solid #1679b8;border-radius:14px;padding:24px;box-shadow:inset 0 0 30px #0aa0ff12,0 14px 40px #0007}.hero{display:grid;grid-template-columns:1.4fr 1fr;gap:20px;align-items:stretch}.hero h1{font-size:52px;margin:10px 0;color:#fff}.hero p{color:var(--muted);font-size:20px;line-height:1.7}.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin-top:20px}.mode{min-height:190px;display:flex;flex-direction:column;justify-content:space-between}.mode h2{color:var(--cyan);margin:0}.mode p{color:var(--muted);line-height:1.6}.form{display:grid;gap:14px;max-width:520px;margin:50px auto}.form h1{text-align:center;color:var(--cyan)}label{display:grid;gap:6px;color:var(--muted)}input,select,textarea{width:100%;padding:12px;color:#fff;background:#071a33;border:1px solid #286187;border-radius:7px}textarea{min-height:90px}.row{display:flex;gap:12px;align-items:center;flex-wrap:wrap}.grid2{display:grid;grid-template-columns:1fr 1fr;gap:16px}.table{width:100%;border-collapse:collapse;margin-top:16px}.table th,.table td{padding:12px;border-bottom:1px solid #1b4768;text-align:center}.table th{color:var(--gold)}.pill{display:inline-block;padding:5px 9px;border-radius:20px;background:#123e65;color:var(--cyan)}.game{display:grid;gap:18px}.hud{display:flex;justify-content:space-between;align-items:center}.score{font-size:34px;color:var(--gold)}.question{font-size:32px;line-height:1.6;text-align:center;padding:25px}.battle-question{font-size:24px;line-height:1.5;text-align:center;padding:16px 12px}.battle-question-side{text-align:left}.answers{display:grid;grid-template-columns:1fr 1fr;gap:16px}.answers button{min-height:82px;font-size:24px}.versus{display:grid;grid-template-columns:1fr auto 1fr;gap:16px;align-items:center}.versus .side{padding:20px;text-align:center}.versus strong{font-size:24px}.center{text-align:center}.big{font-size:64px;color:var(--gold)}.notice{padding:14px;border-radius:8px;background:#18334f;color:var(--muted)}.error{background:#4b2035;color:#ffd3da}.list{display:grid;gap:12px}.list-item{display:flex;justify-content:space-between;align-items:center;padding:14px;border:1px solid #1a5379;border-radius:8px;background:#081c35}.muted{color:var(--muted)}
:root{}
.mode{width:100%;min-height:190px;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:12px;text-align:center;padding:24px}.mode h2{margin:0}.mode p{max-width:280px;margin:0}.mode:hover h2{color:#fff}.import-box{margin-top:20px;padding-top:20px;border-top:1px solid #1b4768}.import-box input[type=file]{max-width:560px}.import-actions{margin-top:12px}.import-preview{margin-top:14px;overflow:auto;max-height:330px}.import-preview .table{margin-top:0}
.form-help{margin-top:10px;color:var(--muted);font-size:13px;line-height:1.5}.form-error{margin-bottom:14px}.form input:invalid:not(:placeholder-shown),.form textarea:invalid:not(:placeholder-shown),#studentForm input:invalid:not(:placeholder-shown),#groupForm input:invalid:not(:placeholder-shown),#questionForm input:invalid:not(:placeholder-shown),#questionForm textarea:invalid:not(:placeholder-shown){border-color:var(--danger);box-shadow:0 0 0 2px #ff758833}.form label,.grid2 label{min-width:0}
.role-switch button.selected{border-color:var(--gold);color:var(--gold);box-shadow:0 0 0 2px #ffd56a33,0 0 16px #ffd56a22}
.solo-head{display:flex;justify-content:space-between;align-items:flex-end;gap:20px;margin-bottom:20px}.solo-head h1{margin:0 0 8px;color:var(--cyan);font-size:38px}.tabs{display:flex;gap:8px}.tabs button.selected{border-color:var(--gold);color:var(--gold);box-shadow:0 0 0 2px #ffd56a33}.stage-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.stage-tile{min-height:220px;text-align:left;display:block}.stage-tile h2{color:var(--cyan);margin:18px 0 8px}.stage-tile p{color:var(--muted);min-height:26px}.stage-tile small{color:var(--muted)}.progress{height:9px;border-radius:5px;background:#071426;overflow:hidden;margin:20px 0 10px}.progress i{display:block;height:100%;background:linear-gradient(90deg,var(--cyan),var(--gold));border-radius:inherit}.lesson-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.lesson-tile{display:flex;flex-direction:column;justify-content:space-between;min-height:230px;padding:20px;border:1px solid #1a668f;border-radius:8px;background:#071a33}.lesson-tile h3{margin:10px 0 8px;color:#fff;font-size:20px;line-height:1.45}.lesson-tile p{margin:0;color:var(--muted)}.lesson-unit{font-size:13px;color:var(--cyan)}.lesson-result{margin:18px 0 10px;color:var(--gold)}.lesson-tile.locked{opacity:.55;border-color:#34495e}.lesson-tile button:disabled{cursor:not-allowed;filter:none;transform:none}.compact{padding:7px 12px;min-height:34px;margin-bottom:12px}.question-meta{text-align:center;color:var(--cyan)}.solo-game .answers button:disabled{opacity:1;cursor:default}.answers button.answer-correct{background:#124d3a;border-color:#54e6a5;color:#bfffe0}.answers button.answer-wrong{background:#612437;border-color:#ff7588;color:#ffd3da}.feedback-correct{color:#7dffbd;font-weight:700}.feedback-box{padding:18px;border:1px solid #8d5e2a;background:#302515;border-radius:8px;color:#fff}.feedback-box p{color:#d8c7ad;line-height:1.6}.feedback-box button{margin-top:8px}.quit-practice{justify-self:center}.settlement{max-width:760px;margin:30px auto}.centered{justify-content:center;margin-top:22px}.warning{background:#4a3b19;color:#ffe5a0}
.grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.grid4{display:grid;grid-template-columns:repeat(4,1fr);gap:12px}.spread{justify-content:space-between}.battle-setup{display:grid;gap:20px}.participant-box{padding:18px;border:1px solid #1a668f;background:#071a33;border-radius:8px}.participant-box h2{margin:0 0 14px;color:var(--cyan)}.participant-box .row h2{margin:0}.versus-picker{display:grid;grid-template-columns:1fr auto 1fr;align-items:center;gap:18px}.versus-picker>b,.vs-mark{font-size:30px;color:var(--gold);text-align:center}.fixed-player{display:flex;flex-direction:column;justify-content:center;min-height:72px;padding:14px;border:1px solid #286187;border-radius:7px;background:#0b2747;text-align:center}.fixed-player strong{font-size:22px}.fixed-player span,.battle-side small{display:block;margin-top:5px;color:var(--muted)}.content-picker{padding:0}.question-pick-head{display:flex;justify-content:space-between;align-items:end;gap:20px}.question-pick-head h2{margin:0 0 5px}.question-pick-head p{margin:0}.question-picker{max-height:430px;overflow:auto;display:grid;gap:9px;padding-right:8px}.question-choice{display:grid;grid-template-columns:24px 1fr;gap:10px;align-items:start;padding:12px;border:1px solid #1a5379;border-radius:7px;background:#081c35;color:#eef8ff;line-height:1.55}.question-choice input{width:18px;height:18px;margin-top:3px}.question-choice b{display:block;margin-bottom:3px;color:var(--gold)}.duel-grid{display:grid;grid-template-columns:1fr 64px 1fr;gap:14px;align-items:center}.team-battle-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:14px}.battle-side{padding:18px;border:1px solid #1a668f;border-radius:8px;background:#071a33}.team-head{display:flex;justify-content:space-between;align-items:start;gap:12px;margin-bottom:14px}.team-head strong{font-size:24px}.team-head>strong{font-size:34px;color:var(--gold)}.battle-options{display:grid;grid-template-columns:1fr 1fr;gap:10px}.battle-options button{min-height:66px;text-align:left;font-size:18px}.battle-feedback{margin-top:4px;text-align:center}.timer{display:grid;place-items:center;width:58px;height:58px;border:2px solid var(--gold);border-radius:50%;font-size:26px;font-weight:800;color:var(--gold);box-shadow:0 0 20px #ffd56a33}.rotation{max-width:620px;margin:70px auto}.duel-result{display:grid;grid-template-columns:1fr auto 1fr;gap:20px;align-items:center;margin:25px 0}.duel-result article{display:grid;gap:10px}.duel-result strong{font-size:24px}.duel-result span{font-size:64px;color:var(--gold)}.duel-result>b{font-size:44px}.team-result-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:14px;margin:24px 0}.team-result-grid article{display:grid;gap:8px;padding:18px;border:1px solid #1a668f;border-radius:8px;background:#071a33}.team-result-grid span{color:var(--cyan)}.team-result-grid strong{font-size:25px}.team-result-grid b{font-size:34px;color:var(--gold)}.team-result-grid small{color:var(--muted);line-height:1.5}
.choice-groups{display:grid;grid-template-columns:repeat(2,1fr);gap:14px}.choice-group{padding:14px;border:1px solid #1a5379;border-radius:8px;background:#081c35}.choice-group h3{margin:0 0 10px;color:var(--gold)}.choice-list{display:flex;flex-wrap:wrap;gap:9px}.choice-chip{min-height:42px;padding:8px 14px;background:#122541;border-color:#43617e}.choice-chip.selected{background:#155d48;border-color:#54e6a5;color:#caffea;box-shadow:0 0 0 2px #54e6a533}.choice-chip.fixed{background:#244c63;border-color:var(--cyan);color:#fff;cursor:not-allowed}.team-choice-list{padding:14px;border:1px solid #1a5379;border-radius:8px;background:#081c35}.lesson-picker{padding:18px;border:1px solid #1a668f;border-radius:8px;background:#071a33}.lesson-picker h2{margin:0 0 14px;color:var(--cyan);font-weight:700}.lesson-picker .content-picker{display:grid;padding:0 0 16px;border:0;border-bottom:1px solid #1b4768}.lesson-picker .content-picker label{color:var(--cyan);font-weight:700}.lesson-label{margin:16px 0 10px;color:var(--cyan);font-size:16px;font-weight:700}.lesson-choice-list{display:flex;flex-wrap:wrap;gap:9px}.lesson-choice{min-height:42px;padding:8px 14px;background:#122541;border-color:#43617e}.lesson-choice.selected{background:#155d48;border-color:#54e6a5;color:#caffea}.fixed-note{margin-bottom:12px;padding:10px 12px;border-left:3px solid var(--cyan);background:#0b2747;color:#d9f8ff}.ranking-grid{display:grid;grid-template-columns:1fr 1fr;gap:20px;margin-top:20px}.ranking-box{padding:18px;border:1px solid #1a668f;border-radius:8px;background:#071a33}.ranking-box h2{text-align:center;color:var(--cyan);margin:0}.manage-page,.questions-page{display:grid;gap:20px}.manage-section,.question-list-section{padding:18px;border:1px solid #1a668f;border-radius:8px;background:#071a33}.manage-section h2{margin:0}.filter-label{display:flex;align-items:center;gap:8px}.filter-label select{min-width:180px}.student-table-wrap,.table-wrap{overflow:auto}.student-table td{vertical-align:middle}.student-table td:last-child{white-space:nowrap}.pagination-head{margin-top:16px}.pagination-head label{display:flex;align-items:center;gap:8px}.pagination-head select{width:auto}.page-actions{margin-top:16px}.modal-backdrop{position:fixed;inset:0;z-index:20;display:grid;place-items:center;padding:24px;background:#02040bcc}.modal-card{width:min(720px,calc(100vw - 48px));max-height:90vh;overflow:auto;padding:24px;border:1px solid #269bd8;border-radius:10px;background:#071a33;box-shadow:0 20px 80px #000b}.modal-card h2{margin:0;color:var(--cyan)}.modal-form{display:grid;gap:14px;margin-top:18px}.modal-form>.secondary{justify-self:start}.question-option-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:12px}.question-option-grid[hidden]{display:none}.inline-add{justify-self:start}.ranking-box .table{margin-top:14px}
.answers button.selected,.battle-options button.selected{background:#155d48;border-color:#54e6a5;color:#caffea;box-shadow:0 0 0 2px #54e6a533}.confirm-multiple{justify-self:center;min-width:180px}.battle-side .confirm-multiple{width:100%;margin-top:10px}.multiple-answer-picker{margin:0;padding:12px;border:1px solid #286187;border-radius:7px}.multiple-answer-picker legend{padding:0 6px;color:var(--muted)}.multiple-answer-picker>div{display:grid;grid-template-columns:repeat(4,1fr);gap:10px}.multiple-answer-picker label{display:flex;align-items:center;justify-content:center;gap:8px;padding:10px;border:1px solid #1a5379;border-radius:7px;background:#081c35;color:#eef8ff}.multiple-answer-picker input{width:18px;height:18px;padding:0}.confirm-multiple:disabled{cursor:not-allowed;filter:none;transform:none;opacity:.5}

/* Compact battle setup without clipping participant or lesson content. */
.battle-setup{gap:12px}
.battle-title-row{align-items:center;margin-bottom:0}
.battle-title-row h1{margin:0;font-size:32px}
.answer-mode-tabs{margin-left:auto}
.answer-mode-tabs button{min-height:38px;padding:8px 14px}
.participant-box{padding:14px 16px}
.participant-box h2{margin:0}
.participant-box>p.muted{margin:9px 0 0;font-size:14px}
.choice-groups{gap:10px}
.choice-group{padding:10px 12px}
.choice-group-row{display:flex;align-items:flex-start;gap:10px}
.choice-group-row h3{flex:0 0 64px;margin:8px 0 0;font-size:15px}
.choice-group-row .choice-list{flex:1;min-width:0}
.choice-list{gap:8px}
.choice-chip{min-height:38px;padding:7px 12px}
.team-choice-list{padding:11px 12px}
.lesson-picker{padding:14px 16px}
.lesson-picker-head{display:flex;align-items:flex-end;gap:16px}
.lesson-picker-head h2{flex:0 0 auto;margin:0 0 10px}
.lesson-picker-head .content-picker{display:grid;flex:1;padding:0;border:0}
.lesson-label{margin:10px 0 8px;font-size:15px}
.lesson-choice-list{gap:8px}
.lesson-choice{min-height:38px;padding:7px 12px}
.battle-start-row{display:flex;align-items:center;gap:12px}
.battle-start-row .notice{flex:1;min-width:0;padding:11px 12px}
.battle-start-row>button{flex:0 0 auto}
.fixed-note{margin-bottom:10px;padding:8px 10px}

/* Web responsive layout */
body{min-width:0;overflow-x:hidden}
.shell,.content,.topbar{width:100%}
.nav{justify-content:flex-end}
.battle-side,.panel,.question{min-width:0;overflow-wrap:anywhere}
@media (max-width:1099px){
  .shell{padding:18px 20px}.topbar{align-items:flex-start;margin-bottom:18px}.brand{font-size:25px}
  .hero h1{font-size:40px}.cards,.stage-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
  .team-battle-grid,.duel-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}.duel-grid .vs-mark{display:none}
  .question{font-size:22px;padding:18px}.battle-question{font-size:19px;padding:12px}
  .table-wrap,.student-table-wrap{max-width:100%;overflow-x:auto}
}
@media (max-width:767px){
  body{font-size:15px}.shell{padding:10px}.topbar{display:block;margin:6px 0 12px}.brand{font-size:22px;letter-spacing:1px}.subtitle{font-size:11px}
  .nav{margin-top:10px;flex-wrap:nowrap;overflow-x:auto;justify-content:flex-start;padding-bottom:6px}.nav button{flex:0 0 auto}
  .panel{padding:14px;border-radius:10px}.hero,.cards,.stage-grid,.lesson-grid,.ranking-grid,.grid2,.grid3,.grid4,.choice-groups,.team-battle-grid,.duel-grid,.answers,.battle-options,.question-option-grid{grid-template-columns:1fr}
  .hero h1{font-size:32px}.hero p{font-size:16px}.mode{min-height:135px}.solo-head{display:block}.solo-head .tabs{margin-top:12px}
  .question{font-size:19px;line-height:1.5;padding:12px}.battle-question{font-size:17px}.answers button,.battle-options button{min-height:52px;font-size:16px}
  .hud{gap:8px;flex-wrap:wrap}.timer{width:48px;height:48px;font-size:22px}.team-head strong{font-size:19px}.team-head>strong{font-size:26px}
  .modal-backdrop{padding:8px}.modal-card{width:calc(100vw - 16px);max-height:96vh;padding:14px}
  .row.spread{align-items:flex-start}.filter-label{display:grid;width:100%}.filter-label select{min-width:0}
  .battle-title-row,.lesson-picker-head,.battle-start-row{display:block}.answer-mode-tabs{margin:10px 0}.battle-start-row>button{width:100%;margin-top:10px}
}

.class-name-display{font-size:42px}
body{min-width:0}
.lesson-tile.coming-soon{opacity:.58}
.lesson-tile.coming-soon button:disabled,.lesson-choice:disabled{cursor:not-allowed;filter:none;transform:none;opacity:.65}
@media (max-width:767px){.question{font-size:19px}.battle-question{font-size:17px}.answers button,.battle-options button{font-size:16px}}
.team-order-box{display:grid;gap:14px}
.team-order-columns{display:grid;grid-template-columns:1fr 54px 1fr;gap:12px;align-items:center}
.team-order-card{padding:14px;border:1px solid #1a5379;border-radius:8px;background:#081c35}
.team-order-card h3{margin:0 0 10px;color:var(--cyan);text-align:center}
.team-order-card ol{display:grid;gap:7px;margin:0;padding-left:28px}
.team-order-card li{padding:5px 8px;border-radius:6px;background:#0b2747;color:#fff}
.team-round-list{display:grid;gap:8px;max-height:320px;overflow:auto}
.team-round-row{display:grid;grid-template-columns:86px 52px 1fr 36px 1fr;gap:8px;align-items:center;padding:9px 12px;border:1px solid #1a5379;border-radius:7px;background:#071a33;text-align:center}
.team-round-row span{color:var(--gold);font-weight:700}.team-round-row small{color:var(--muted)}
.team-round-row strong{color:#fff}.team-round-row b{color:var(--gold)}
.team-score{text-align:right}.team-score b{display:block;font-size:30px;color:var(--gold)}.team-score small{color:var(--muted)}
.side-timer{text-align:center;color:var(--muted);margin-bottom:10px}
.rotation-side .big{margin:10px auto}.member-score-table{margin-top:12px;overflow:auto}
.member-score-table .table{margin-top:0;font-size:14px}.member-score-table th,.member-score-table td{padding:7px 6px}
@media (max-width:767px){.team-order-columns{grid-template-columns:1fr}.team-order-columns>.vs-mark{display:none}.team-round-row{grid-template-columns:70px 44px 1fr 24px 1fr;padding:8px 6px}.team-score b{font-size:24px}.team-result-grid{grid-template-columns:1fr}.member-score-table .table{font-size:13px}}
.team-order-columns{display:none!important}
.team-head .team-name{font-size:20px;color:var(--gold)}
.team-head .member-line{font-size:24px;color:#fff;font-weight:800;line-height:1.25}
@media (min-width:768px){.team-battle-grid{grid-template-columns:repeat(2,minmax(0,1fr));align-items:start}.team-side{padding:14px}.team-side .battle-options{gap:8px}.team-side .battle-options button{min-height:58px;font-size:17px;padding:9px 10px}}
@media (max-width:767px){.team-battle-grid{grid-template-columns:1fr}.team-head .team-name{font-size:20px}.team-head .member-line{font-size:24px}}
.team-battle-grid{grid-template-columns:minmax(0,1fr) 64px minmax(0,1fr);align-items:center}
.team-head .team-name{font-size:20px;color:var(--gold)}
.team-head .member-line{font-size:24px;color:#fff;font-weight:800;line-height:1.25}
@media (min-width:768px){.team-battle-grid{grid-template-columns:minmax(0,1fr) 64px minmax(0,1fr);align-items:start}}
@media (max-width:767px){.team-battle-grid{grid-template-columns:1fr}.team-battle-grid>.vs-mark{display:none}.team-head .team-name{font-size:20px}.team-head .member-line{font-size:24px}}
.question{font-size:34px}.battle-question{font-size:26px}
@media (max-width:1099px){.question{font-size:24px}.battle-question{font-size:21px}}
@media (max-width:767px){.question{font-size:21px}.battle-question{font-size:19px}}
.duel-grid,.team-battle-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;align-items:start}
@media (max-width:1099px){.duel-grid,.team-battle-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}}
@media (max-width:767px){.duel-grid,.team-battle-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:8px}.battle-side{padding:10px}.battle-options{grid-template-columns:1fr;gap:6px}.battle-options button{min-height:46px;font-size:14px;padding:7px 8px}}
/* Full viewport layout and login exit action. */
html,body,#app{width:100%;height:100%}
html{min-width:0}
body{min-width:0;min-height:100%;overflow-x:hidden}
.shell{width:100%;height:100vh;height:100dvh;min-height:100vh;min-height:100dvh;overflow-x:hidden;overflow-y:auto}
.topbar,.content{width:100%;max-width:none;margin-left:0;margin-right:0}
.login-actions{display:grid;gap:10px}
.login-actions button{width:100%}
.ranking-head{align-items:flex-start}
.ranking-actions{align-items:center;justify-content:flex-end}
.ranking-actions .tabs{flex-wrap:wrap}
@media (max-width:767px){.ranking-head{display:block}.ranking-actions{justify-content:flex-start;margin-top:10px}.ranking-actions .tabs{flex-wrap:wrap}.ranking-actions .danger{width:100%}}
.game .battle-side{min-height:0;max-height:min(72dvh,720px);overflow-y:auto;overscroll-behavior-y:contain;scrollbar-gutter:stable}