:root{--bg: #f4f6fb;--surface: #ffffff;--surface-soft: #f8fafc;--text: #0f172a;--muted: #64748b;--border: #e2e8f0;--primary: #4f46e5;--primary-2: #7c3aed;--success: #059669;--danger: #dc2626;--ring: rgba(79, 70, 229, .18);--shadow-sm: 0 4px 14px rgba(2, 8, 23, .06);--shadow-md: 0 12px 28px rgba(2, 8, 23, .08);--radius-sm: 10px;--radius-md: 14px}*{box-sizing:border-box}body{margin:0;background:radial-gradient(circle at top right,#eef2ff 0%,var(--bg) 38%,#f8fafc 100%);color:var(--text);font-family:Inter,system-ui,-apple-system,Segoe UI,Roboto,sans-serif}.app-shell{min-height:100vh}.app-header{position:sticky;top:0;z-index:10;-webkit-backdrop-filter:blur(6px);backdrop-filter:blur(6px);background:rgba(255,255,255,.9);border-bottom:1px solid var(--border)}.app-header-inner{max-width:1200px;margin:0 auto;padding:18px 24px 14px}.app-brand-row{display:flex;justify-content:space-between;align-items:center;margin-bottom:14px;gap:12px}.app-title{margin:0;font-size:28px;letter-spacing:-.02em}.app-subtle{color:var(--muted);font-size:14px}.app-nav{display:flex;gap:10px;flex-wrap:wrap}.nav-btn{border:1px solid var(--border);border-radius:999px;padding:9px 15px;font-size:14px;font-weight:600;color:#334155;background:#fff;cursor:pointer;transition:all .18s ease}.nav-btn:hover{box-shadow:var(--shadow-sm)}.nav-btn.active{color:#fff;border-color:transparent;background:linear-gradient(135deg,var(--primary),var(--primary-2))}.pattern-bar{height:4px;background:linear-gradient(90deg,#4f46e5 0%,#7c3aed 45%,#06b6d4 100%)}.main-container{max-width:1200px;margin:0 auto;padding:28px 24px}.panel{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-md);box-shadow:var(--shadow-sm);padding:24px}.panel+.panel{margin-top:16px}.section-title{margin:0 0 6px;font-size:24px;letter-spacing:-.02em}.section-subtitle{margin:0 0 20px;color:var(--muted)}.form-grid{display:grid;gap:14px;margin-bottom:20px}.form-row-2{display:grid;grid-template-columns:1fr 1fr;gap:14px}.field-label{display:block;font-size:13px;font-weight:600;color:#334155;margin-bottom:6px}.form-control{width:100%;padding:10px 12px;border:1px solid var(--border);border-radius:var(--radius-sm);font-size:14px;background:#fff;color:var(--text)}.form-control:focus{outline:none;border-color:#818cf8;box-shadow:0 0 0 4px var(--ring)}.btn{border:1px solid transparent;border-radius:var(--radius-sm);padding:10px 14px;font-weight:600;font-size:14px;cursor:pointer;transition:all .18s ease}.btn:disabled{opacity:.55;cursor:not-allowed}.btn-block{width:100%;padding:12px 16px;font-size:15px}.btn-primary{color:#fff;background:linear-gradient(135deg,var(--primary),var(--primary-2))}.btn-primary:hover:not(:disabled),.btn-success:hover:not(:disabled),.btn-soft:hover:not(:disabled){transform:translateY(-1px);box-shadow:var(--shadow-md)}.btn-soft{color:#1e293b;background:#fff;border-color:var(--border)}.btn-success{color:#fff;background:linear-gradient(135deg,#10b981,var(--success))}.btn-danger{color:#991b1b;background:#fee2e2;border-color:#fecaca}.alert{border-radius:var(--radius-sm);padding:12px;font-size:14px;line-height:1.4;margin-bottom:12px}.alert-error{background:#fef2f2;border:1px solid #fecaca;color:#991b1b}.alert-info{background:#eff6ff;border:1px solid #bfdbfe;color:#1e3a8a}.flash-card{text-align:left;border:1px solid var(--border);border-radius:16px;padding:20px;min-height:170px;cursor:pointer;box-shadow:var(--shadow-md);transition:transform .18s ease,box-shadow .18s ease;background:#fff;color:#0f172a}.flash-card:hover{transform:translateY(-1px)}.flash-card.flipped{background:#111827;color:#f9fafb}.card-meta{font-size:12px;opacity:.72;margin-bottom:8px}.card-text{font-size:22px;font-weight:700;line-height:1.35}.card-hint{margin-top:12px;font-size:12px;opacity:.62}.card-nav{display:flex;align-items:center;justify-content:space-between;margin-top:12px;gap:10px}.card-nav-center{font-size:13px;color:var(--muted)}.saved-grid{display:grid;gap:16px}.saved-header{display:flex;justify-content:space-between;align-items:start;gap:12px;margin-bottom:14px}.saved-meta{display:flex;flex-wrap:wrap;gap:14px;font-size:13px;color:var(--muted)}.progress-track{margin-top:10px;height:8px;border-radius:999px;background:#e2e8f0;overflow:hidden}.progress-fill{height:100%;border-radius:999px;background:linear-gradient(90deg,var(--primary),var(--primary-2))}.empty-state{text-align:center;padding:48px}.inline-grid{display:grid;gap:10px}@media (max-width: 780px){.main-container{padding:20px 14px}.app-header-inner{padding:14px}.form-row-2{grid-template-columns:1fr}.card-text{font-size:20px}}