:root {
    --bg-color: #0f172a;
    --card-bg: rgba(30, 41, 59, 0.7);
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-lime: #B4F218;
    --accent-lime-hover: #9bd312;
    --border-color: rgba(255, 255, 255, 0.1);
    --danger: #ef4444;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Inter', sans-serif;
}

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
    padding: 20px;
    background-image: radial-gradient(circle at top right, rgba(180, 242, 24, 0.05), transparent 40%),
                      radial-gradient(circle at bottom left, rgba(180, 242, 24, 0.05), transparent 40%);
    background-attachment: fixed;
}

.app-container {
    max-width: 600px;
    margin: 0 auto;
}

header {
    margin-bottom: 30px;
    text-align: center;
}

.header-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.header-top h1 {
    font-size: 2rem;
    margin: 0;
}

header h1 {
    font-weight: 700;
    font-size: 2.5rem;
    letter-spacing: -1px;
}

.lime-dot {
    color: var(--accent-lime);
}

header p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-top: 5px;
}

/* Cards & Glassmorphism */
.card {
    background: var(--card-bg);
    border-radius: 16px;
    padding: 20px;
    margin-bottom: 25px;
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.1);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.card h2 {
    font-size: 1.2rem;
    margin-bottom: 15px;
    font-weight: 600;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* Dashboard */
.dashboard-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.toggle-currency {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

select.filter-select, .toggle-currency select {
    background: rgba(15, 23, 42, 0.8);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    padding: 5px 10px;
    border-radius: 8px;
    outline: none;
    font-size: 0.85rem;
}

.balances {
    display: flex;
    justify-content: space-between;
    gap: 15px;
    margin-bottom: 20px;
}

.balance-item {
    flex: 1;
    background: rgba(0,0,0,0.2);
    padding: 15px;
    border-radius: 12px;
    text-align: center;
    border: 1px solid rgba(255,255,255,0.05);
}

.balance-item .person-name {
    display: block;
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.balance-item h3 {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--accent-lime);
}

.settlement {
    text-align: center;
    padding-top: 15px;
    border-top: 1px solid var(--border-color);
    font-size: 0.95rem;
}

/* Forms */
.input-group {
    margin-bottom: 15px;
    display: flex;
    flex-direction: column;
    flex: 1;
}

.row {
    display: flex;
    gap: 15px;
}

label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 6px;
}

input, select {
    background: rgba(15, 23, 42, 0.5);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 12px 15px;
    border-radius: 10px;
    font-size: 1rem;
    outline: none;
    transition: all 0.3s ease;
}

input:focus, select:focus {
    border-color: var(--accent-lime);
    box-shadow: 0 0 0 2px rgba(180, 242, 24, 0.2);
}

.btn-primary {
    background-color: var(--accent-lime);
    color: #000;
    font-weight: 600;
    border: none;
    padding: 14px;
    width: 100%;
    border-radius: 10px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-top: 10px;
}

.btn-primary:hover {
    background-color: var(--accent-lime-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(180, 242, 24, 0.3);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-secondary {
    background-color: transparent;
    color: var(--accent-lime);
    font-weight: 600;
    border: 1px solid var(--accent-lime);
    padding: 14px;
    width: 100%;
    border-radius: 10px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-top: 10px;
}

.btn-secondary:hover {
    background-color: rgba(180, 242, 24, 0.1);
}

.btn-logout {
    background: transparent;
    color: var(--danger);
    border: 1px solid var(--danger);
    padding: 6px 12px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.8rem;
    font-weight: 600;
    transition: all 0.3s ease;
}

.btn-logout:hover {
    background: rgba(239, 68, 68, 0.1);
}

.auth-error {
    color: var(--danger);
    font-size: 0.85rem;
    margin-top: 5px;
    text-align: center;
    min-height: 20px;
}

/* List */
.list-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    padding: 0 5px;
}

.list-header h2 {
    font-size: 1.2rem;
    font-weight: 600;
}

#expenses-ul {
    list-style: none;
}

.expense-item {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 15px;
    margin-bottom: 12px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: transform 0.2s;
}

.expense-item:hover {
    transform: translateX(5px);
    border-color: rgba(255,255,255,0.2);
}

.expense-info {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.expense-desc {
    font-weight: 600;
    font-size: 1rem;
}

.expense-meta {
    font-size: 0.75rem;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 8px;
}

.badge {
    background: rgba(255,255,255,0.1);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.7rem;
    color: var(--text-primary);
}

.badge-a { border-left: 3px solid #3b82f6; }
.badge-b { border-left: 3px solid #ec4899; }

.expense-amounts {
    text-align: right;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.amount-main {
    font-weight: 700;
    font-size: 1.1rem;
    color: var(--accent-lime);
}

.amount-sub {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.empty-state {
    text-align: center;
    padding: 30px;
    color: var(--text-secondary);
    font-size: 0.9rem;
    background: var(--card-bg);
    border-radius: 12px;
    border: 1px dashed var(--border-color);
}

@media (max-width: 480px) {
    .row {
        flex-direction: column;
        gap: 0;
    }
}