:root{color-scheme:light;--bg:#dfe3e6;--panel:#f8f9fa;--white:#fff;--line:#aeb5bb;--line2:#c9ced2;--ink:#17191b;--muted:#5e6469;--dark:#3f454a;--light:#eceff1;--current:#4b5156}
*{box-sizing:border-box;-webkit-tap-highlight-color:transparent}html,body{margin:0;min-height:100%;font-family:Arial,"Segoe UI",sans-serif;background:var(--bg);color:var(--ink)}button,a{font:inherit}button{cursor:pointer}.start-screen,.result-screen{min-height:100vh;min-height:100dvh;padding:max(22px,env(safe-area-inset-top)) max(16px,env(safe-area-inset-right)) max(22px,env(safe-area-inset-bottom)) max(16px,env(safe-area-inset-left));display:grid;place-items:center}.start-box,.result-box{width:min(520px,100%);background:#f5f6f7;border:1px solid var(--line);box-shadow:4px 4px 0 #c0c5c9;padding:26px;text-align:center}.start-box h1,.result-box h1{margin:0 0 6px;font-size:1.7rem}.start-box>p{color:var(--muted)}dl{display:grid;grid-template-columns:repeat(3,1fr);border:1px solid var(--line);margin:20px 0;background:#fff}dl div{padding:12px 6px;border-left:1px solid var(--line2)}dl div:last-child{border-left:0}dt{font-size:.78rem;color:var(--muted)}dd{margin:5px 0 0;font-weight:800;font-size:1.15rem}.start-note{font-size:.88rem;line-height:1.65}.plain-primary,.subject-chooser button{width:100%;border:1px solid #6d7479;background:linear-gradient(#fefefe,#dfe3e6);padding:13px;font-weight:800;margin-top:8px;min-height:44px}.plain-primary:active,.subject-chooser button:active{background:#cdd2d6}.plain-link{display:block;color:#222;margin-top:14px}.subject-chooser{display:grid;gap:8px;margin:15px 0}
.exam-app{min-height:100vh;min-height:100dvh;display:grid;grid-template-columns:minmax(0,1fr) 184px;gap:14px;padding:max(12px,env(safe-area-inset-top)) max(14px,env(safe-area-inset-right)) max(14px,env(safe-area-inset-bottom)) max(14px,env(safe-area-inset-left));direction:ltr}.exam-main,.question-index{direction:rtl}.exam-main{min-width:0;display:flex;flex-direction:column;gap:12px}.exam-header{display:grid;grid-template-columns:150px 1fr 170px;align-items:stretch;border:1px solid var(--line);background:linear-gradient(#f9fafb,#e8ebed);min-height:78px;box-shadow:2px 2px 0 #c8cdd1}.finish-btn{border:0;border-left:1px solid var(--line);background:transparent;font-weight:700;color:#333;min-height:44px}.exam-title{display:flex;flex-direction:column;justify-content:center;text-align:center;gap:4px}.exam-title b{font-size:1.32rem}.exam-title span{font-size:.83rem;color:var(--muted)}.timer-box{display:flex;flex-direction:column;align-items:center;justify-content:center;border-right:1px solid var(--line);gap:3px}.timer-box span{font-size:.75rem;color:var(--muted)}.timer-box b{font-size:1.28rem}.question-panel,.answer-panel{border:1px solid var(--line);background:var(--white);box-shadow:2px 2px 0 #c8cdd1}.question-panel{padding:18px;min-height:260px}.question-head{display:flex;justify-content:space-between;align-items:center;border-bottom:1px solid var(--line2);padding-bottom:10px;color:var(--muted);font-size:.84rem}.question-head b{font-size:1rem;color:#222}.question-panel h2{font-size:clamp(1.12rem,2.2vw,1.55rem);line-height:1.65;text-align:center;margin:24px auto;max-width:860px}.visual-wrap{border:1px solid var(--line2);background:#fff;padding:8px;text-align:center;margin:0 auto 6px;max-width:820px}.visual-wrap img{display:block;max-width:100%;max-height:42vh;margin:auto;object-fit:contain}.answer-panel{padding:14px}.answer-texts{display:grid;gap:0;border:1px solid var(--line2)}.answer-text{display:grid;grid-template-columns:42px 1fr;align-items:center;min-height:54px;border-bottom:1px solid var(--line2);background:#fff}.answer-text:last-child{border-bottom:0}.answer-letter{display:grid;place-items:center;height:100%;border-left:1px solid var(--line2);font-weight:800;background:#f0f2f3}.answer-copy{padding:10px 13px;line-height:1.45}.answer-selector{display:flex;justify-content:center;gap:clamp(18px,6vw,80px);padding:18px 10px 4px;direction:rtl}.choice-btn{width:50px;height:50px;border-radius:50%;border:2px solid #303438;background:#fff;font-size:1.25rem;font-weight:800}.choice-btn.selected{background:#33383c;color:#fff;box-shadow:inset 0 0 0 4px #fff}.bottom-row{display:grid;grid-template-columns:minmax(0,1fr) 170px;gap:12px;margin-top:auto}.selected-status,.next-btn{min-height:70px;border:1px solid var(--line);box-shadow:2px 2px 0 #c8cdd1}.selected-status{display:grid;place-items:center;background:#fff;font-size:1rem}.next-btn{background:linear-gradient(#fafafa,#dfe3e6);font-size:1.2rem;font-weight:800}.next-btn:active{background:#cbd0d4}.question-index{border:1px solid var(--line);background:#eef0f2;box-shadow:2px 2px 0 #c1c6ca;display:flex;flex-direction:column;min-height:calc(100vh - 28px);min-height:calc(100dvh - 28px);position:sticky;top:14px;max-height:calc(100vh - 28px);max-height:calc(100dvh - 28px)}.question-index h2{font-size:1rem;text-align:center;margin:0;padding:15px 5px;border-bottom:1px solid var(--line);background:linear-gradient(#f8f9fa,#e1e5e8)}.index-grid{padding:8px;display:grid;grid-template-columns:repeat(2,1fr);gap:4px;overflow:auto;overscroll-behavior:contain}.index-btn{height:40px;min-height:40px;border:1px solid var(--line2);background:#fff;font-weight:700}.index-btn.answered{background:#d6dade}.index-btn.current{background:var(--current);color:#fff;border-color:#24272a}.index-legend{margin-top:auto;padding:8px;border-top:1px solid var(--line);font-size:.68rem;display:grid;gap:5px;background:#f6f7f8}.index-legend span{display:flex;align-items:center;gap:5px}.sample{width:13px;height:13px;border:1px solid var(--line2);background:#fff}.sample.current{background:var(--current)}.sample.answered{background:#d6dade}.dialog-layer{position:fixed;inset:0;background:rgba(0,0,0,.35);z-index:30;display:grid;place-items:center;padding:20px}.dialog-box{width:min(390px,100%);background:#f4f5f6;border:1px solid #777;padding:20px;box-shadow:6px 6px 0 rgba(0,0,0,.2);text-align:center}.dialog-box h2{margin-top:0}.dialog-box div{display:flex;gap:8px}.dialog-box button{flex:1;padding:10px;min-height:44px;border:1px solid #777;background:linear-gradient(#fff,#ddd)}.result-box{max-width:500px}.result-percent{font-size:4.5rem;font-weight:900;margin:18px}.result-state{font-size:1.35rem}.result-actions{display:grid;gap:8px;margin-top:20px}.result-actions button,.result-actions a{border:1px solid #777;background:linear-gradient(#fff,#ddd);padding:12px;min-height:44px;text-decoration:none;color:#111}.review-mode .finish-btn{visibility:hidden}
[hidden]{display:none!important}
@media(max-width:720px){.exam-app{grid-template-columns:minmax(0,1fr) 96px;gap:7px;padding:7px}.question-index{top:7px;max-height:calc(100vh - 14px);max-height:calc(100dvh - 14px);min-height:calc(100vh - 14px);min-height:calc(100dvh - 14px)}.question-index h2{font-size:.75rem;padding:10px 2px}.index-grid{padding:4px;gap:3px}.index-btn{height:36px;min-height:36px;font-size:.8rem}.index-legend{display:none}.exam-header{grid-template-columns:78px 1fr 88px;min-height:64px}.finish-btn{font-size:.72rem;padding:3px}.exam-title b{font-size:.95rem}.exam-title span{font-size:.66rem}.timer-box b{font-size:.93rem}.timer-box span{font-size:.62rem}.question-panel{padding:11px;min-height:220px}.question-panel h2{font-size:1rem;line-height:1.55;margin:16px 0}.visual-wrap img{max-height:30vh}.answer-panel{padding:7px}.answer-text{grid-template-columns:32px 1fr;min-height:45px}.answer-copy{font-size:.84rem;padding:8px}.answer-selector{gap:12px;padding:12px 2px 3px}.choice-btn{width:44px;height:44px;font-size:1rem}.bottom-row{grid-template-columns:minmax(0,1fr) 78px;gap:7px}.selected-status,.next-btn{min-height:57px;font-size:.78rem}.next-btn{font-size:.93rem}.start-box,.result-box{padding:18px}dl{grid-template-columns:1fr}dl div{border-left:0;border-bottom:1px solid var(--line2)}dl div:last-child{border-bottom:0}}
@media(max-width:390px){.exam-app{grid-template-columns:minmax(0,1fr) 84px}.index-btn{height:34px;min-height:34px;font-size:.73rem}.answer-copy{font-size:.78rem}.choice-btn{width:42px;height:42px}.question-panel h2{font-size:.94rem}}

/* V5.7.0 — mobile stability, dynamic viewport and larger touch targets */
button{touch-action:manipulation}
.resume-hint{margin:8px 0 0;padding:9px;border:1px solid var(--line2);background:#fff;font-size:.8rem;color:var(--muted)}
.exam-app,.exam-main,.question-index,.question-panel,.answer-panel{overflow-anchor:none}
.question-index,.question-panel,.answer-panel,.bottom-row{contain:layout paint}
.index-grid{scrollbar-gutter:stable;contain:layout paint}
.index-btn{contain:layout paint}
.visual-wrap{position:relative;display:grid;place-items:center;min-height:90px;overflow:hidden;contain:layout paint;background:#fafafa}
.visual-wrap img{grid-area:1/1;opacity:0;transition:opacity .12s linear}
.visual-wrap img.ready{opacity:1}
.visual-status{grid-area:1/1;color:var(--muted);font-size:.85rem;z-index:1}
.visual-wrap.failed{aspect-ratio:auto!important;min-height:90px}
.timer-box b.urgent{font-weight:900;text-decoration:underline}
.answer-selector{contain:layout paint}
.choice-btn{transition:none}
.answer-text.review-correct{outline:2px solid #333;outline-offset:-2px}
.answer-text.review-wrong{text-decoration:line-through;text-decoration-thickness:2px}
@media(max-width:720px){
  .exam-header{position:sticky;top:7px;z-index:8}
  .question-index{z-index:7}
  .visual-wrap{min-height:70px}
  .bottom-row{position:sticky;bottom:max(7px,env(safe-area-inset-bottom));z-index:6;background:var(--bg);padding-top:3px}
}
@media(max-width:390px){
  .exam-app{grid-template-columns:minmax(0,1fr) 78px;gap:5px;padding:5px}
  .question-index{top:5px;max-height:calc(100vh - 10px);max-height:calc(100dvh - 10px);min-height:calc(100vh - 10px);min-height:calc(100dvh - 10px)}
  .index-grid{padding:3px;gap:2px}.index-btn{height:34px;min-height:34px;font-size:.7rem}
  .exam-header{top:5px;grid-template-columns:70px 1fr 82px}
  .answer-selector{gap:8px}.choice-btn{width:42px;height:42px}
  .bottom-row{grid-template-columns:minmax(0,1fr) 72px;gap:5px}
}
@media(prefers-reduced-motion:reduce){.visual-wrap img{transition:none}}