:root {
    --primary: #4F46E5; --primary-dark: #4338ca; --secondary: #10B981; --danger: #EF4444;
    --bg-body: #F3F4F6; --bg-card: #FFFFFF; --text-main: #1F2937; --text-muted: #6B7280; --border: #E5E7EB; --radius: 12px;
}
* { box-sizing: border-box; margin: 0; padding: 0; font-family: 'Inter', sans-serif; }
body { background-color: var(--bg-body); color: var(--text-main); min-height: 100vh; display: flex; justify-content: center; align-items: center; }
.hidden { display: none !important; }
.btn { padding: 0.75rem 1.5rem; border-radius: var(--radius); border: none; cursor: pointer; font-weight: 600; transition: 0.2s; display: inline-flex; align-items: center; gap: 0.5rem; }
.btn-primary { background: var(--primary); color: white; } .btn-primary:hover { background: var(--primary-dark); }
.btn-secondary { background: white; border: 1px solid var(--border); color: var(--text-main); } .btn-danger { background: var(--danger); color: white; }
input, textarea { width: 100%; padding: 0.75rem; border: 1px solid var(--border); border-radius: var(--radius); margin-bottom: 1rem; outline: none; }
input:focus { border-color: var(--primary); }
.card { background: var(--bg-card); padding: 1.5rem; border-radius: var(--radius); box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1); }
#auth-container { width: 100%; max-width: 400px; }
#app-container { width: 100%; height: 100vh; max-width: 1200px; display: flex; background: var(--bg-body); }
@media (min-width: 768px) {
    body { align-items: flex-start; padding: 2rem; }
    #app-container { height: 90vh; border-radius: 20px; overflow: hidden; box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1); }
}
.sidebar { background: var(--bg-card); width: 250px; padding: 1.5rem; display: flex; flex-direction: column; border-right: 1px solid var(--border); }
@media (max-width: 767px) {
    .sidebar { position: fixed; bottom: 0; left: 0; width: 100%; height: auto; flex-direction: row; justify-content: space-around; padding: 0.8rem; z-index: 10; border-top: 1px solid var(--border); border-right: none; }
    .nav-item span { display: none; } .nav-item { flex-direction: column; font-size: 0.7rem; }
}
.nav-item { display: flex; align-items: center; gap: 0.8rem; padding: 0.8rem; color: var(--text-muted); text-decoration: none; border-radius: var(--radius); margin-bottom: 0.5rem; cursor: pointer; }
.nav-item.active, .nav-item:hover { background: rgba(79, 70, 229, 0.1); color: var(--primary); font-weight: 600; }
.main-content { flex: 1; padding: 1.5rem; overflow-y: auto; position: relative; }
@media (max-width: 767px) { .main-content { padding-bottom: 80px; } }
.wallet-card { background: linear-gradient(135deg, var(--primary), var(--primary-dark)); color: white; padding: 2rem; border-radius: 16px; margin-bottom: 2rem; }
.balance-amount { font-size: 2rem; font-weight: 700; }
.transaction-item { display: flex; justify-content: space-between; align-items: center; padding: 1rem 0; border-bottom: 1px solid var(--border); }
.trans-icon { width: 40px; height: 40px; border-radius: 50%; display: flex; align-items: center; justify-content: center; margin-right: 1rem; font-size: 1.2rem; }
.trans-icon.plus { background: #D1FAE5; color: #065F46; } .trans-icon.minus { background: #FEE2E2; color: #991B1B; }
.avatar-small { width: 40px; height: 40px; border-radius: 50%; object-fit: cover; border: 2px solid var(--primary); }
#toast-container { position: fixed; top: 20px; right: 20px; z-index: 9999; }
.toast { background: white; padding: 1rem; border-radius: var(--radius); box-shadow: var(--shadow); margin-bottom: 10px; border-left: 4px solid var(--primary); display: flex; align-items: center; gap: 10px; animation: slideIn 0.3s; }
.toast.success { border-left-color: var(--secondary); } .toast.error { border-left-color: var(--danger); }
@keyframes slideIn { from { transform: translateX(100%); } to { transform: translateX(0); } }