:root{--primary: #4f46e5;--primary-dark: #3730a3;--bg-color: #f8fafc;--surface: #ffffff;--text-main: #0f172a;--text-light: #64748b;--success: #10b981;--danger: #ef4444;--border: #e2e8f0;--shadow-sm: 0 2px 8px rgba(0,0,0,.04);--shadow-lg: 0 12px 32px rgba(0,0,0,.08);--max-width: 1200px;--opt-correct-bg: #ecfdf5;--opt-correct-border: #10b981;--opt-correct-text: #065f46;--opt-wrong-bg: #fef2f2;--opt-wrong-border: #ef4444;--opt-wrong-text: #991b1b}[data-theme=dark]{--bg-color: #0f172a;--surface: #1e293b;--text-main: #f8fafc;--text-light: #94a3b8;--border: #334155;--shadow-sm: 0 4px 12px rgba(0,0,0,.3);--shadow-lg: 0 12px 32px rgba(0,0,0,.4);--opt-correct-bg: rgba(16, 185, 129, .1);--opt-correct-border: #059669;--opt-correct-text: #34d399;--opt-wrong-bg: rgba(239, 68, 68, .1);--opt-wrong-border: #dc2626;--opt-wrong-text: #f87171}*{box-sizing:border-box;-webkit-tap-highlight-color:transparent;user-select:none}body{margin:0;padding:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,Helvetica Neue,sans-serif;background-color:var(--bg-color);color:var(--text-main);overscroll-behavior-y:none;transition:background-color .3s,color .3s;text-rendering:optimizeLegibility;-webkit-font-smoothing:antialiased}.header-wrapper{width:100%;background:var(--surface);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:50;transition:background-color .3s}.app-bar{max-width:var(--max-width);margin:0 auto;padding:12px 16px;display:flex;align-items:center;justify-content:space-between;gap:12px}.app-bar-left{display:flex;align-items:center;gap:10px;min-width:0;text-decoration:none;color:inherit}.app-bar-left img{width:34px;height:34px;border-radius:50%;object-fit:cover;border:1px solid var(--border)}.app-bar-title{font-size:15px;font-weight:800;margin:0;color:var(--text-main);letter-spacing:-.3px;white-space:nowrap}.app-bar-right{display:flex;align-items:center;gap:8px}.app-nav{display:flex;align-items:center;gap:4px}.app-nav a{color:var(--text-light);text-decoration:none;font-size:13px;font-weight:700;padding:8px 10px;border-radius:10px}.app-nav a:hover{color:var(--text-main);background:var(--bg-color)}.theme-toggle{background:var(--bg-color);border:1px solid var(--border);color:var(--text-main);width:34px;height:34px;border-radius:50%;display:flex;align-items:center;justify-content:center;cursor:pointer;font-size:15px;transition:all .2s}.theme-toggle:active{transform:scale(.9)}.app-wrapper{display:flex;flex-direction:column;width:100%;max-width:var(--max-width);margin:0 auto;min-height:calc(100dvh - 59px);position:relative}.app-content{flex:1;padding:16px 16px 25px;width:100%}.site-footer{margin-top:auto;padding:24px 16px 32px;border-top:1px solid var(--border);text-align:center}.site-footer-links{display:flex;justify-content:center;gap:16px;margin-bottom:16px;flex-wrap:wrap}.site-footer-links a{color:var(--text-light);text-decoration:none;font-size:13px;font-weight:700}.site-footer-links a:hover{color:var(--primary)}.site-footer p{margin:0;font-size:12px;color:var(--text-light);font-weight:500}.bottom-nav{position:fixed;bottom:calc(12px + env(safe-area-inset-bottom));left:50%;transform:translate(-50%);width:calc(100% - 24px);max-width:calc(var(--max-width) - 24px);background:var(--surface);padding:12px 16px;border:1px solid var(--border);border-radius:20px;display:flex;align-items:center;justify-content:center;gap:10px;box-shadow:var(--shadow-lg);z-index:40;transition:background-color .3s}.nav-btn{flex:1;padding:12px 8px;border-radius:12px;border:none;font-size:14px;font-weight:700;cursor:pointer;transition:all .2s;display:flex;align-items:center;justify-content:center;gap:4px}.nav-btn:active{transform:scale(.96)}.nav-btn:disabled{opacity:.4;pointer-events:none}.nav-btn-outline{background:var(--surface);color:var(--text-main);border:1.5px solid var(--border)}.nav-btn-danger{background:#ef44440d;color:var(--danger);border:1.5px solid rgba(239,68,68,.2)}.nav-btn-primary{background:var(--primary);color:#fff;box-shadow:0 4px 12px #4f46e54d}.option-btn{background-color:var(--surface);border:2px solid var(--border);color:var(--text-main);padding:18px 20px;border-radius:16px;font-size:15px;font-weight:600;cursor:pointer;transition:all .2s ease;line-height:1.5;box-shadow:var(--shadow-sm)}.option-btn:active{transform:scale(.98)}.option-btn.correct{background-color:var(--opt-correct-bg)!important;border-color:var(--opt-correct-border)!important;color:var(--opt-correct-text)!important}.option-btn.wrong{background-color:var(--opt-wrong-bg)!important;border-color:var(--opt-wrong-border)!important;color:var(--opt-wrong-text)!important}@media (max-width: 640px){.app-nav a:nth-child(3){display:none}.site-footer{padding-bottom:110px}}