/* ============ 基础 ============ */
* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: -apple-system, "Microsoft YaHei", "Segoe UI", sans-serif; background: #f5f5f7; color: #1d1d1f; line-height: 1.6; }
.container { max-width: 900px; margin: 0 auto; padding: 20px; }

/* ============ 登录页 ============ */
.login-page { display: flex; justify-content: center; align-items: center; min-height: 100vh; }
.login-box { background: #fff; border-radius: 16px; padding: 48px; box-shadow: 0 4px 24px rgba(0,0,0,0.08); text-align: center; max-width: 480px; width: 100%; }
.login-box h1 { font-size: 24px; margin-bottom: 24px; color: #1d1d1f; }
.exam-info { background: #f5f5f7; border-radius: 12px; padding: 16px; margin-bottom: 24px; text-align: left; }
.exam-info p { font-size: 14px; color: #666; margin: 4px 0; }
.login-box input[type=text], .login-box input[type=password] {
    width: 100%; padding: 14px 16px; border: 2px solid #e5e5e7; border-radius: 10px;
    font-size: 16px; outline: none; transition: border-color 0.2s;
}
.login-box input:focus { border-color: #0071e3; }
.login-box button { width: 100%; padding: 14px; margin-top: 16px; background: #0071e3; color: #fff; border: none; border-radius: 10px; font-size: 16px; cursor: pointer; transition: background 0.2s; }
.login-box button:hover { background: #0077ed; }
.flash { background: #fff3cd; color: #856404; padding: 10px 16px; border-radius: 8px; margin-bottom: 16px; }
.flash.success { background: #d4edda; color: #155724; }

/* ============ 考试未开放 ============ */
.closed-info { margin: 24px 0; }
.closed-info p { font-size: 16px; margin: 8px 0; }
.btn-back { display: inline-block; padding: 10px 24px; background: #0071e3; color: #fff; text-decoration: none; border-radius: 8px; margin-top: 16px; }

/* ============ 考试页顶栏 ============ */
.exam-header {
    position: fixed; top: 0; left: 0; right: 0; z-index: 100;
    background: #fff; border-bottom: 1px solid #e5e5e7;
    display: flex; align-items: center; justify-content: space-between;
    padding: 12px 24px; box-shadow: 0 2px 8px rgba(0,0,0,0.06);
}
.header-left { font-size: 15px; }
.header-center { font-size: 14px; color: #666; }
.header-right { display: flex; align-items: center; gap: 12px; }
.timer { font-size: 22px; font-weight: 700; font-variant-numeric: tabular-nums; color: #1d1d1f; }
.timer.time-warning { color: #ff3b30; animation: pulse 1s infinite; }
.timer.time-up { color: #ff3b30; }
@keyframes pulse { 50% { opacity: 0.5; } }
.btn-submit-top { padding: 8px 16px; background: #ff3b30; color: #fff; border: none; border-radius: 8px; font-size: 14px; cursor: pointer; }

/* ============ 考试页内容 ============ */
.exam-page { margin-top: 72px; padding-bottom: 100px; }
.section { margin-bottom: 40px; }
.section h2 { font-size: 18px; color: #1d1d1f; padding: 12px 0; border-bottom: 2px solid #0071e3; margin-bottom: 20px; }
.section-hint { font-size: 13px; color: #888; margin-bottom: 16px; }

.question { display: flex; gap: 12px; padding: 16px; margin-bottom: 8px; border-radius: 10px; background: #fff; border: 2px solid transparent; transition: border-color 0.2s; }
.question.answered { border-color: #34c759; background: #f0fff4; }
.q-number { font-weight: 700; color: #0071e3; min-width: 32px; font-size: 15px; }
.q-body { flex: 1; }
.q-text { font-size: 15px; margin-bottom: 10px; line-height: 1.7; }

/* 选项 */
.q-options { display: flex; flex-direction: column; gap: 6px; }
.tf-options { flex-direction: row; gap: 16px; }
.option-label { display: flex; align-items: center; gap: 8px; padding: 8px 12px; border-radius: 8px; cursor: pointer; transition: background 0.15s; font-size: 14px; }
.option-label:hover { background: #f5f5f7; }
.option-label input[type=radio] { accent-color: #0071e3; }

/* 填空 */
.fill-input { width: 100%; max-width: 400px; padding: 10px 14px; border: 2px solid #e5e5e7; border-radius: 8px; font-size: 15px; outline: none; }
.fill-input:focus { border-color: #0071e3; }

/* 文本框 */
.text-answer { width: 100%; min-height: 80px; padding: 12px; border: 2px solid #e5e5e7; border-radius: 8px; font-size: 14px; font-family: inherit; resize: vertical; outline: none; }
.opinion-answer { min-height: 120px; }
.text-answer:focus { border-color: #0071e3; }

/* 交卷 */
.submit-area { text-align: center; padding: 40px 0; }
.btn-submit { padding: 16px 48px; background: #ff3b30; color: #fff; border: none; border-radius: 12px; font-size: 18px; cursor: pointer; transition: background 0.2s; }
.btn-submit:hover { background: #e0332b; }
.submit-hint { color: #888; font-size: 13px; margin-top: 8px; }

/* ============ 成绩页 ============ */
.result-page { display: flex; justify-content: center; align-items: center; min-height: 100vh; }
.result-card { background: #fff; border-radius: 16px; padding: 48px; box-shadow: 0 4px 24px rgba(0,0,0,0.08); text-align: center; max-width: 500px; width: 100%; }
.result-card h1 { font-size: 22px; margin-bottom: 8px; }
.result-name { font-size: 18px; color: #666; margin-bottom: 24px; }
.score-display { margin: 24px 0; }
.score-number { font-size: 72px; font-weight: 800; }
.score-label { font-size: 18px; color: #888; }
.score-display.pass .score-number { color: #34c759; }
.score-display.fail .score-number { color: #ff3b30; }
.score-display.pending .score-number { color: #ff9500; }
.score-detail { font-size: 14px; color: #666; margin: 16px 0; }
.result-badge { display: inline-block; padding: 8px 24px; border-radius: 20px; font-size: 16px; font-weight: 600; margin: 16px 0; }
.pass-badge { background: #d4edda; color: #155724; }
.fail-badge { background: #f8d7da; color: #721c24; }
.pending-badge { background: #fff3cd; color: #856404; }
.submit-info { font-size: 13px; color: #999; margin-top: 24px; }

/* ============ 管理后台 ============ */
.admin-page h1 { font-size: 22px; margin-bottom: 20px; }
.admin-table { width: 100%; border-collapse: collapse; background: #fff; border-radius: 12px; overflow: hidden; box-shadow: 0 2px 12px rgba(0,0,0,0.06); }
.admin-table th { background: #1d1d1f; color: #fff; padding: 12px 16px; font-size: 13px; text-align: left; }
.admin-table td { padding: 10px 16px; border-bottom: 1px solid #f0f0f0; font-size: 13px; }
.admin-table tr:hover { background: #f9f9f9; }
.row-pass { background: #f0fff4 !important; }
.row-fail { background: #fff5f5 !important; }
.badge { display: inline-block; padding: 3px 10px; border-radius: 12px; font-size: 12px; font-weight: 600; }
.badge.pass { background: #d4edda; color: #155724; }
.badge.fail { background: #f8d7da; color: #721c24; }
.badge.pending { background: #fff3cd; color: #856404; }
.badge.progress { background: #cce5ff; color: #004085; }
.btn-small { display: inline-block; padding: 4px 12px; border-radius: 6px; font-size: 12px; text-decoration: none; margin: 2px; }
.btn-grade { background: #0071e3; color: #fff; }
.btn-danger { background: #ff3b30; color: #fff; }
.btn-small:hover { opacity: 0.8; }

/* ============ 批阅页 ============ */
.grade-page h1 { font-size: 22px; margin-bottom: 12px; }
.grade-card { background: #fff; border-radius: 12px; padding: 20px; margin-bottom: 16px; box-shadow: 0 2px 8px rgba(0,0,0,0.04); }
.grade-q { display: flex; align-items: center; gap: 8px; margin-bottom: 8px; }
.grade-qid { font-weight: 700; color: #0071e3; }
.grade-qtype { font-size: 12px; background: #f0f0f0; padding: 2px 8px; border-radius: 4px; }
.grade-qtext { font-size: 15px; margin-bottom: 12px; line-height: 1.6; }
.grade-answer { margin-bottom: 12px; }
.answer-content { background: #f5f5f7; padding: 12px; border-radius: 8px; margin-top: 4px; font-size: 14px; white-space: pre-wrap; }
.grade-ref { margin-bottom: 12px; }
.ref-content { background: #e8f5e9; padding: 12px; border-radius: 8px; margin-top: 4px; font-size: 13px; color: #2e7d32; }
.grade-score { display: flex; align-items: center; gap: 8px; }
.grade-score select { padding: 6px 12px; border: 2px solid #e5e5e7; border-radius: 6px; font-size: 14px; }

/* ============ 响应式 ============ */
@media (max-width: 768px) {
    .exam-header { padding: 8px 12px; font-size: 13px; }
    .timer { font-size: 18px; }
    .container { padding: 12px; }
    .question { padding: 12px; }
    .admin-table { font-size: 12px; }
    .admin-table th, .admin-table td { padding: 6px 8px; }
}