:root {
    /* Color Palette */
    --bg-dark: #f8fafc;
    --bg-card-dark: rgba(255, 255, 255, 0.85);
    --text-main: #0f172a;
    --text-muted: #64748b;
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --success: #10b981;
    --danger: #ef4444;
    --warning: #f59e0b;
    --border: rgba(0, 0, 0, 0.1);
    --glass-border: rgba(255, 255, 255, 0.6);
    
    /* Typography */
    --font-family: 'Inter', sans-serif;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background-color: var(--bg-dark);
    color: var(--text-main);
    font-family: var(--font-family);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    background-image: radial-gradient(circle at 15% 50%, rgba(99, 102, 241, 0.15), transparent 25%),
                      radial-gradient(circle at 85% 30%, rgba(16, 185, 129, 0.15), transparent 25%);
    background-attachment: fixed;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    margin-bottom: 1rem;
}

p {
    line-height: 1.6;
}

a {
    color: var(--primary);
    text-decoration: none;
    transition: color 0.3s ease;
}
a:hover {
    color: var(--primary-hover);
}

/* Glassmorphism Card */
.glass-card {
    background: var(--bg-card-dark);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    padding: 2rem;
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.1);
}

/* Navbar */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 1000;
}
.nav-brand {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-main);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}
.nav-links {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}
.mobile-menu-btn {
    display: none; /* hidden on desktop */
}
.nav-links a {
    color: var(--text-muted);
    font-weight: 500;
}
.nav-links a:hover {
    color: var(--text-main);
}
.btn-logout {
    background: rgba(239, 68, 68, 0.1);
    color: var(--danger) !important;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    border: 1px solid rgba(239, 68, 68, 0.2);
}
.btn-logout:hover {
    background: var(--danger);
    color: #fff !important;
}

/* Layout */
.container {
    flex: 1;
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
    animation: fadeIn 0.5s ease-out;
}

/* Forms */
.form-group {
    margin-bottom: 1.5rem;
}
.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-size: 0.875rem;
    color: var(--text-muted);
}
.form-control {
    width: 100%;
    padding: 0.75rem 1rem;
    background: rgba(255, 255, 255, 0.9);
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text-main);
    font-family: var(--font-family);
    transition: all 0.3s ease;
}
.form-control:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-weight: 600;
    text-align: center;
    cursor: pointer;
    border: none;
    transition: all 0.3s ease;
}
.btn-primary {
    background: var(--primary);
    color: #fff;
}
.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
}
.btn-success {
    background: var(--success);
    color: #fff;
}
.btn-success:hover {
    background: #059669;
}
.btn-danger {
    background: var(--danger);
    color: #fff;
}
.btn-danger:hover {
    background: #dc2626;
}

/* Tables */
.table-responsive {
    overflow-x: auto;
}
.table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
}
.table th, .table td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
}
.table th {
    color: var(--text-muted);
    font-weight: 500;
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}
.table tbody tr {
    transition: background-color 0.2s ease;
}
.table tbody tr:hover {
    background-color: rgba(0, 0, 0, 0.02);
}

/* Badges */
.badge {
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
}
.badge-pending {
    background: rgba(245, 158, 11, 0.2);
    color: var(--warning);
}
.badge-paid {
    background: rgba(16, 185, 129, 0.2);
    color: var(--success);
}
.badge-rejected {
    background: rgba(239, 68, 68, 0.2);
    color: var(--danger);
}

/* Auth Pages */
.auth-wrapper {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: calc(100vh - 140px);
}
.auth-card {
    width: 100%;
    max-width: 400px;
}

/* Dashboard Stats */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}
.stat-card {
    display: flex;
    align-items: center;
    gap: 1rem;
}
.stat-icon {
    width: 48px;
    height: 48px;
    border-radius: 12px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.5rem;
}
.stat-icon.primary { background: rgba(99, 102, 241, 0.2); color: var(--primary); }
.stat-icon.success { background: rgba(16, 185, 129, 0.2); color: var(--success); }
.stat-icon.warning { background: rgba(245, 158, 11, 0.2); color: var(--warning); }

.stat-content h3 {
    margin: 0;
    font-size: 0.875rem;
    color: var(--text-muted);
}
.stat-content p {
    margin: 0;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-main);
}

/* Alerts */
.alert {
    padding: 1rem;
    border-radius: 8px;
    margin-bottom: 1.5rem;
}
.alert-error {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.2);
    color: #fca5a5;
}
.alert-success {
    background: rgba(16, 185, 129, 0.1);
    border: 1px solid rgba(16, 185, 129, 0.2);
    color: #6ee7b7;
}

/* Footer */
.footer {
    padding: 2rem;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.875rem;
    border-top: 1px solid var(--border);
    margin-top: auto;
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Select element styling */
select.form-control {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 24 24' stroke='%230f172a'%3E%3Cpath stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='M19 9l-7 7-7-7'%3E%3C/path%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 1rem center;
    background-size: 1em;
}
select.form-control option {
    background: #ffffff;
    color: var(--text-main);
}

/* Mobile Responsiveness */
@media (max-width: 768px) {
    /* Navbar adjustments */
    .navbar {
        flex-direction: row;
        flex-wrap: wrap;
        justify-content: space-between;
        padding: 1rem;
        position: relative; /* Remove sticky to save screen space */
    }
    .mobile-menu-btn {
        display: block;
        background: none;
        border: none;
        font-size: 1.5rem;
        color: var(--text-main);
        cursor: pointer;
    }
    .nav-links {
        display: none; /* hidden by default on mobile */
        width: 100%;
        flex-direction: column;
        align-items: stretch;
        gap: 0.75rem;
        margin-top: 1rem;
        background: var(--bg-card-dark);
        padding: 1rem;
        border-radius: 8px;
        border: 1px solid var(--border);
    }
    .nav-links.show-mobile {
        display: flex;
    }
    .nav-links a, .nav-links form, .nav-links button {
        width: 100%;
        text-align: center;
    }
    .nav-links a {
        font-size: 0.9rem;
    }
    
    /* Layout padding reductions */
    .container {
        padding: 1rem;
    }
    .glass-card {
        padding: 1rem;
    }

    /* Headings */
    h2 {
        font-size: 1.25rem;
    }
    h3 {
        font-size: 1.1rem;
    }

    /* Stats Grid */
    .stats-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    /* Table wrappers */
    .table-responsive {
        margin-top: 1rem;
        border-radius: 8px;
        box-shadow: inset 0 0 5px rgba(0,0,0,0.05);
    }
    
    /* Forms that are flexed inline */
    form[style*="display: flex"] {
        flex-direction: column;
        align-items: stretch !important;
    }
    form[style*="display: flex"] > .form-group {
        width: 100% !important;
        flex: none !important;
    }
    form[style*="display: grid"] {
        grid-template-columns: 1fr !important;
    }
    form[style*="display: grid"] > div {
        grid-column: 1 / -1 !important;
    }
    
    /* Any flex row that holds totals or balances */
    div[style*="display: flex; gap: 1.5rem;"] {
        flex-direction: column;
        gap: 0.5rem !important;
    }
    
    /* Auth pages */
    .auth-wrapper {
        min-height: calc(100vh - 200px);
    }
}