:root{--navy:#0b3158;--blue:#0f6cbd;--teal:#008573;--bg:#f4f7fb;--card:#fff;--text:#172033;--muted:#667085;--border:#d8e1eb;--danger:#b42318}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);font-family:"Segoe UI","Microsoft YaHei UI",sans-serif}.site-header{min-height:70px;padding:0 max(24px,calc((100% - 1180px)/2));display:flex;align-items:center;justify-content:space-between;background:linear-gradient(115deg,var(--navy),#075b78);color:#fff}.brand{font-size:1.25rem;font-weight:700;color:#fff;text-decoration:none}.site-header nav{display:flex;align-items:center;gap:20px}.site-header nav a,.link-button{color:#fff;text-decoration:none}.site-header form{margin:0}.link-button{font:inherit;border:0;background:none;cursor:pointer;padding:0}.container{max-width:1180px;margin:0 auto;padding:42px 24px 70px}.page-heading{display:flex;align-items:end;justify-content:space-between;gap:24px;margin-bottom:28px}h1{font-size:clamp(2rem,4vw,3rem);line-height:1.05;margin:.15em 0}.eyebrow,.topic{color:var(--teal);font-size:.78rem;font-weight:800;text-transform:uppercase;letter-spacing:.1em}.card{background:var(--card);border:1px solid var(--border);border-radius:18px;box-shadow:0 8px 26px rgba(11,49,88,.07)}.level-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}.level-card{padding:26px}.level-number{display:grid;place-items:center;width:48px;height:48px;border-radius:14px;background:#eaf3fb;color:var(--blue);font-size:1.3rem;font-weight:800}.locked{opacity:.62}.button{display:inline-block;border:0;border-radius:10px;padding:11px 16px;font:inherit;font-weight:700;text-decoration:none;cursor:pointer}.primary{background:var(--blue);color:#fff}.secondary{background:#eaf3fb;color:var(--navy)}.lesson-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:18px}.lesson-card{padding:24px}.lesson-card h2{font-size:2rem;margin:.35em 0}.pinyin{color:var(--blue);font-style:italic}.speech-actions,.actions{display:flex;gap:10px;flex-wrap:wrap}.auth-card,.result-card{max-width:520px;margin:8vh auto;padding:38px}.stacked-form{display:grid;gap:18px}.stacked-form label{display:grid;gap:7px;font-weight:600}.stacked-form input{width:100%;padding:12px;border:1px solid var(--border);border-radius:9px;font:inherit}.stacked-form small{color:var(--muted);line-height:1.45}.stacked-form small ul{margin:.4rem 0;padding-left:1.2rem}.field-error{padding:10px 12px;border-radius:8px;background:#fee4e2;color:var(--danger)}.auth-switch{text-align:center;margin:24px 0 0}.auth-switch a{color:var(--blue);font-weight:700}.alert{padding:14px 16px;border-radius:10px;background:#eaf3fb;margin:18px 0}.alert.error{background:#fee4e2;color:var(--danger)}.alert.success{background:#d1fadf;color:#05603a}.question-card{padding:22px;margin-bottom:18px}.question-card legend{padding:6px 12px;border-radius:8px;background:var(--navy);color:#fff;font-weight:700}.question-card h2{font-size:1.2rem}.option{display:block;margin:10px 0;padding:12px;border:1px solid var(--border);border-radius:9px;cursor:pointer}.option:hover{background:#f0f7ff}.submit-exam{width:100%;font-size:1.05rem}.result-card{text-align:center}.result-card h1{font-size:clamp(2rem,6vw,4.2rem);color:var(--blue)}.result-card .actions{justify-content:center}.table-card{overflow:auto}table{width:100%;border-collapse:collapse}th,td{text-align:left;padding:15px;border-bottom:1px solid var(--border)}th{background:#eaf3fb}.passed{color:#067647;font-weight:700}.failed{color:var(--danger);font-weight:700}@media(max-width:800px){.level-grid{grid-template-columns:repeat(2,1fr)}.lesson-grid{grid-template-columns:1fr}.site-header{align-items:flex-start;gap:15px;padding-block:18px}.site-header,.page-heading{flex-direction:column}.site-header nav{flex-wrap:wrap}}@media(max-width:520px){.level-grid{grid-template-columns:1fr}.container{padding-inline:16px}.auth-card{padding:25px}.site-header nav{gap:12px}}