:root{--bg: #f7f8fa;--panel: #ffffff;--panel-soft: #f2f5fb;--text: #111827;--muted: #6b7280;--primary: #1f2a44;--primary-2: #253456;--accent-mint: #2dd4bf;--accent-cyan: #22d3ee;--border: #e5e7eb;--danger: #dc2626;--warning: #f59e0b;--success: #16a34a;--radius-sm: 8px;--radius-md: 12px;--radius-lg: 16px;--shadow-card: 0 8px 24px rgba(31, 42, 68, .08)}*{box-sizing:border-box}body{margin:0;font-family:Inter,PingFang SC,Microsoft YaHei,system-ui,-apple-system,sans-serif;background:var(--bg);color:var(--text)}a{color:inherit;text-decoration:none}.app-shell{min-height:100vh}.topbar{position:sticky;top:0;z-index:10;display:flex;align-items:center;justify-content:space-between;gap:16px;padding:14px 24px;border-bottom:1px solid var(--border);background:#ffffffe0;-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px)}.brand{font-weight:800;letter-spacing:.3px}.nav{display:flex;gap:8px;flex-wrap:wrap}.nav-link{color:var(--muted);padding:8px 12px;border-radius:10px}.nav-link:hover,.nav-link.active{color:var(--text);background:var(--panel-soft)}.auth-actions{display:flex;gap:10px}.page-container{max-width:1180px;margin:0 auto;padding:24px}.page-container:has(.exam-shell-full),.page-container:has(.home-fullscreen){max-width:none;width:100%;padding:12px 16px}.card,.metric,.panel{background:var(--panel);border:1px solid var(--border);border-radius:var(--radius-md);padding:16px;box-shadow:var(--shadow-card)}.stack{display:flex;flex-direction:column;gap:12px}.row{display:flex;flex-wrap:wrap;gap:10px;align-items:center}.metric-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:12px}.metric .label{color:var(--muted);font-size:13px;margin-bottom:8px}.metric .value{font-size:24px;font-weight:700}.two-col{display:grid;grid-template-columns:1fr 1fr;gap:12px}input,select,textarea{width:100%;background:#fff;color:var(--text);border:1px solid var(--border);border-radius:10px;padding:10px 12px}textarea{resize:vertical}.btn,.primary-btn,.ghost-btn{border:1px solid transparent;border-radius:10px;padding:10px 14px;font-weight:600;cursor:pointer}.btn,.primary-btn{background:linear-gradient(135deg,var(--primary),var(--primary-2));color:#fff}.ghost-btn{background:transparent;border-color:var(--border);color:var(--text)}.primary-btn.small{padding:8px 12px}.table{width:100%;border-collapse:collapse;margin-top:10px}.table th,.table td{border-bottom:1px solid var(--border);padding:10px;text-align:left}.exam-shell{border:1px solid #dde3ee;border-radius:var(--radius-lg);overflow:hidden;background:linear-gradient(180deg,#fcfdff,#f7f9fc);box-shadow:0 10px 30px #1f2a4412}.exam-header{position:sticky;top:0;z-index:5;background:#ffffffeb;border-bottom:1px solid #e6ebf3;-webkit-backdrop-filter:blur(6px);backdrop-filter:blur(6px)}.typing-progress{height:2px;background:linear-gradient(90deg,var(--accent-cyan),var(--accent-mint));transition:width .2s ease}.exam-header-row{display:flex;justify-content:space-between;align-items:center;padding:10px 14px}.timer{font-weight:700;font-size:20px;transition:color .25s ease}.timer.warning{color:var(--warning)}.timer.danger{color:var(--danger)}.chip{padding:6px 10px;border:1px solid var(--border);border-radius:999px;font-size:13px;color:var(--muted)}.exam-body{display:flex;min-height:68vh}.exam-body-three{display:grid;grid-template-columns:3fr 3fr 4fr;gap:0;min-height:calc(100vh - 180px)}.task-area,.writing-area{padding:14px;display:flex;flex-direction:column;gap:12px;min-height:0}.panel.grow{flex:1;overflow:auto}.col-task,.col-sample{border-right:1px solid #e6ebf3}.writing-area{position:relative;min-height:0}.writing-editor{height:100%;min-height:0;border:1px solid #e3e8f2;outline:none;background:#f9fafb;color:#111827;border-radius:12px;line-height:1.75;box-shadow:inset 0 1px 2px #1f2a440a}.floating-word-count{position:absolute;right:24px;bottom:24px;background:#111827e6;color:#fff;border-radius:999px;padding:6px 12px;font-size:12px}.typed-text{line-height:1.9;font-size:16px;white-space:pre-wrap;color:#334155}.typed-text .done{color:#64748b}.typed-text .current{text-decoration:underline;text-underline-offset:3px;color:#1e3a8a;font-weight:600}.typed-text .wrong{background:#ef44442e;color:#991b1b;border-radius:4px}.typed-text .todo{color:#334155}.exam-footer{display:flex;justify-content:space-between;align-items:center;gap:10px;padding:10px 14px;border-top:1px solid #e6ebf3;background:#ffffffeb;-webkit-backdrop-filter:blur(6px);backdrop-filter:blur(6px)}@media (max-width: 900px){.metric-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.exam-body-three{grid-template-columns:1fr;min-height:auto}.col-task,.col-sample{border-right:none;border-bottom:1px solid #e6ebf3}}