:root{--bg: #f5f6f8;--card: #ffffff;--border: #e3e6ea;--text: #1f2329;--muted: #7a828c;--primary: #2563eb;--primary-dark: #1d4ed8;--ac: #16a34a;--wa: #dc2626;--re: #d97706;--tle: #9333ea;--ce: #64748b;--mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace}*{box-sizing:border-box;margin:0;padding:0}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,PingFang SC,Microsoft YaHei,sans-serif;background:var(--bg);color:var(--text);line-height:1.6}a{color:var(--primary);text-decoration:none}h1{font-size:1.6rem;margin-bottom:12px}h2{font-size:1.25rem;margin:16px 0 8px}h3{font-size:1.05rem;margin:12px 0 6px}.navbar{display:flex;align-items:center;justify-content:space-between;padding:0 24px;height:56px;background:var(--card);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:10}.navbar .brand{font-weight:700;color:var(--text);font-size:1.1rem}.navbar nav{display:flex;align-items:center;gap:20px}.navbar nav a{color:var(--muted)}.navbar nav a.router-link-active{color:var(--primary);font-weight:600}.user{color:var(--text);font-weight:600}.content{max-width:1080px;margin:0 auto;padding:24px}.page{animation:fade .2s ease}@keyframes fade{0%{opacity:0;transform:translateY(4px)}to{opacity:1}}.dim{color:var(--muted)}button{padding:8px 16px;border:1px solid var(--border);border-radius:6px;background:var(--card);cursor:pointer;font-size:14px;transition:background .15s}button:hover{background:#f0f2f5}button.primary{background:var(--primary);border-color:var(--primary);color:#fff}button.primary:hover{background:var(--primary-dark)}button:disabled{opacity:.6;cursor:not-allowed}.link-btn{border:none;background:none;color:var(--primary)}input,textarea{width:100%;padding:10px 12px;border:1px solid var(--border);border-radius:6px;font-size:14px;margin-bottom:12px}input:focus,textarea:focus{outline:none;border-color:var(--primary)}.tag{display:inline-block;font-size:12px;padding:2px 8px;border-radius:999px;background:#eef2ff;color:var(--primary);margin-left:8px}.auth-page{display:flex;justify-content:center;padding-top:80px}.auth-card{width:360px;background:var(--card);border:1px solid var(--border);border-radius:10px;padding:28px;text-align:center}.auth-card h1{margin-bottom:20px}.auth-card button{width:100%;margin-top:4px}.auth-card .alt{display:block;margin-top:16px;font-size:14px}.error{color:var(--wa);font-size:13px;margin-bottom:8px;text-align:left}.course-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:16px}.course-card{background:var(--card);border:1px solid var(--border);border-radius:10px;padding:20px;color:var(--text);transition:box-shadow .15s}.course-card:hover{box-shadow:0 4px 16px #00000014}.course-card p{color:var(--muted);font-size:14px;margin-top:6px}.chapter{margin-bottom:16px}.lesson{display:block;background:var(--card);border:1px solid var(--border);border-radius:8px;padding:12px 16px;margin-bottom:8px;color:var(--text)}.lesson:hover{border-color:var(--primary)}.lesson-page .md{background:var(--card);border:1px solid var(--border);border-radius:10px;padding:24px}.md pre{background:#0f172a;color:#e2e8f0;padding:14px;border-radius:8px;overflow-x:auto;font-family:var(--mono);font-size:13px;margin:12px 0}.md code{background:#eef1f5;padding:1px 6px;border-radius:4px;font-family:var(--mono);font-size:13px}.md pre code{background:none;padding:0}.md p{margin:8px 0}.md ul{margin:8px 0 8px 24px}.exercise-link{display:block;margin:8px 0;padding:12px 16px;background:#eef2ff;border-radius:8px;color:var(--primary);font-weight:600}.exercise-page{display:grid;grid-template-columns:1fr 1fr;gap:24px;align-items:start}@media (max-width: 900px){.exercise-page{grid-template-columns:1fr}}.problem{background:var(--card);border:1px solid var(--border);border-radius:10px;padding:24px}.desc{white-space:pre-wrap;font-family:var(--mono);font-size:13px;background:#fafbfc;padding:12px;border-radius:8px;margin:12px 0}.sample{display:grid;grid-template-columns:1fr 1fr;gap:12px}.sample pre{background:#f0f2f5;padding:10px;border-radius:6px;font-family:var(--mono);font-size:13px;white-space:pre-wrap}.editor-side{display:flex;flex-direction:column;gap:12px}.stdin-row label{font-size:13px;color:var(--muted)}.actions{display:flex;gap:12px}.terminal{background:#0f172a;border-radius:8px;overflow:hidden}.term-head{padding:6px 12px;background:#1e293b;color:#94a3b8;font-size:12px}.term-body{padding:12px;color:#e2e8f0;font-family:var(--mono);font-size:13px;min-height:60px;max-height:240px;overflow:auto}.term-body .stdout{white-space:pre-wrap;color:#e2e8f0}.term-body .stderr{white-space:pre-wrap;color:#f87171}.term-body .dim{color:#64748b}.judge{background:var(--card);border:1px solid var(--border);border-radius:10px;padding:16px}.verdict{font-size:1.2rem}.verdict.AC{color:var(--ac)}.verdict.WA{color:var(--wa)}.verdict.RE{color:var(--re)}.verdict.TLE{color:var(--tle)}.verdict.CE{color:var(--ce)}.ce pre{background:#fef2f2;color:var(--wa);padding:12px;border-radius:8px;font-family:var(--mono);font-size:12px;overflow-x:auto;margin-top:8px}.judge table{width:100%;border-collapse:collapse;font-size:13px;margin-top:8px}.judge th,.judge td{border:1px solid var(--border);padding:6px 8px;text-align:left;vertical-align:top}.judge th{background:#fafbfc}.judge td pre{font-family:var(--mono);font-size:12px;white-space:pre-wrap;max-width:200px}.v-AC{color:var(--ac);font-weight:700}.v-WA{color:var(--wa);font-weight:700}.v-RE{color:var(--re);font-weight:700}.v-TLE{color:var(--tle);font-weight:700}.v-CE{color:var(--ce);font-weight:700}.prog-row{display:flex;justify-content:space-between;padding:10px 14px;background:var(--card);border:1px solid var(--border);border-radius:8px;margin-bottom:8px}.prog-row .ok{color:var(--ac);font-weight:700}.prog-row .no{color:var(--muted)}.sub-table{width:100%;border-collapse:collapse;font-size:14px}.sub-table th,.sub-table td{border:1px solid var(--border);padding:8px 10px;text-align:left}.sub-table th{background:var(--card)}.menu-toggle{display:none;position:relative;width:40px;height:40px;border:none;background:none;cursor:pointer;padding:0}.menu-toggle span,.menu-toggle span:before,.menu-toggle span:after{content:"";position:absolute;left:8px;right:8px;height:2px;background:var(--text);border-radius:2px;transition:transform .25s,top .25s}.menu-toggle span{top:19px}.menu-toggle span:before{top:-6px}.menu-toggle span:after{top:6px}.menu-toggle span.open{background:transparent}.menu-toggle span.open:before{top:0;transform:rotate(45deg)}.menu-toggle span.open:after{top:0;transform:rotate(-45deg)}@media (max-width: 768px){.content{padding:16px 12px}.navbar{flex-wrap:wrap;padding:0 16px;height:auto;min-height:56px}.menu-toggle{display:block}.navbar nav{display:none;width:100%;flex-direction:column;align-items:stretch;gap:0;padding:4px 0 12px}.navbar nav.open{display:flex}.navbar nav a{padding:12px 8px;border-radius:8px;font-size:15px}.navbar nav .user{padding:8px;color:var(--muted)}.navbar nav .link-btn{text-align:left;padding:10px 8px;font-size:15px}.sub-table,.data-table{display:block;overflow-x:auto;white-space:nowrap}.exercise-page,.sample{grid-template-columns:1fr}}