:root {
    /* Dark Mode Palette */
    --bg-body: #121212;
    --bg-surface: #1e1e1e;
    --bg-elevated: #2d2d2d;
    --text-primary: #ffffff;
    --text-secondary: #a0a0a0;
    --border-color: #333333;
    --accent-color: #ffffff;
    /* Minimalist accent */
    --danger-color: #ff453a;
    --success-color: #32d74b;
    --input-bg: #2c2c2c;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-body);
    color: var(--text-primary);
    line-height: 1.5;
    padding: 40px 20px;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
}

/* Header */
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 40px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border-color);
}

h1 {
    font-weight: 600;
    font-size: 1.5rem;
    letter-spacing: -0.5px;
}

.trip-selector {
    display: flex;
    gap: 12px;
}

/* Inputs & Buttons */
select,
input[type="text"],
input[type="number"] {
    padding: 10px 16px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-family: inherit;
    font-size: 0.9rem;
    background: var(--input-bg);
    color: var(--text-primary);
    transition: all 0.2s;
}

select:focus,
input:focus {
    outline: none;
    border-color: var(--text-secondary);
    background: var(--bg-elevated);
}

button {
    padding: 10px 20px;
    background: var(--accent-color);
    color: #000;
    border: none;
    border-radius: 6px;
    font-weight: 600;
    cursor: pointer;
    font-size: 0.9rem;
    transition: opacity 0.2s;
}

button:hover {
    opacity: 0.9;
}

button.secondary {
    background: var(--bg-elevated);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

button.danger {
    background: transparent;
    color: var(--danger-color);
    border: 1px solid var(--border-color);
}

/* Layout */
.main-grid {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 50px;
}

.section-title {
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-secondary);
    margin-bottom: 20px;
    font-weight: 600;
}

/* Forms */
.form-group {
    margin-bottom: 30px;
}

.form-row {
    display: flex;
    gap: 10px;
    margin-bottom: 15px;
}

.form-row input {
    flex: 1;
}

.beneficiaries-box {
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    padding: 15px;
    border-radius: 6px;
    margin-bottom: 15px;
}

.checkbox-group {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
    margin-top: 10px;
}

.checkbox-item label {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
    cursor: pointer;
    color: var(--text-secondary);
}

.checkbox-item input:checked+span {
    color: var(--text-primary);
}

/* Lists */
.list-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 0;
    border-bottom: 1px solid var(--border-color);
}

.list-item:last-child {
    border-bottom: none;
}

.expense-details strong {
    display: block;
    font-weight: 500;
    margin-bottom: 4px;
}

.expense-meta {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.expense-amount {
    font-weight: 600;
    font-family: monospace;
    font-size: 1rem;
}

/* Settlements Section */
.settlements-container {
    margin-top: 40px;
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 25px;
}

.settlement-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 15px 0;
    border-bottom: 1px solid var(--border-color);
}

.settlement-item:last-child {
    border-bottom: none;
}

.settlement-visual {
    display: flex;
    align-items: center;
    gap: 15px;
    flex: 1;
}

.person-badge {
    background: var(--bg-elevated);
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
}

.arrow-visual {
    flex: 1;
    height: 1px;
    background: var(--border-color);
    position: relative;
    max-width: 100px;
}

.arrow-visual::after {
    content: '►';
    position: absolute;
    right: -6px;
    top: -8px;
    color: var(--text-secondary);
    font-size: 12px;
}

.settlement-amount {
    font-weight: 600;
    color: var(--success-color);
    font-size: 1.1rem;
    white-space: nowrap;
}

/* Summary Cards */
.summary-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
    margin-bottom: 30px;
}

.summary-card {
    background: var(--bg-surface);
    padding: 20px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.summary-value {
    font-size: 1.8rem;
    font-weight: 600;
    margin-top: 5px;
}

/* Scrollable Expenses List */
.expenses-list-container {
    max-height: 320px;
    overflow-y: auto;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    margin-bottom: 30px;
    background: var(--bg-surface);
}

.expenses-list-container .list-item {
    padding: 16px;
    margin: 0 10px;
}

.expenses-list-container .list-item:last-child {
    border-bottom: none;
}

/* Custom Scrollbar */
.expenses-list-container::-webkit-scrollbar {
    width: 8px;
}

.expenses-list-container::-webkit-scrollbar-track {
    background: var(--bg-surface);
}

.expenses-list-container::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

.expenses-list-container::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

/* Expense Actions */
.expense-actions {
    display: flex;
    gap: 8px;
    margin-left: 15px;
}

.action-icon-btn {
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 6px;
    border-radius: 4px;
    transition: all 0.2s;
    opacity: 0.7;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
}

.action-icon-btn:hover {
    background: var(--bg-elevated);
    opacity: 1;
    color: var(--text-primary);
}

.action-icon-btn svg {
    width: 16px;
    height: 16px;
}

/* Responsive Design */
@media (max-width: 768px) {
    body {
        padding: 20px 15px;
    }

    .main-grid {
        grid-template-columns: 1fr;
        gap: 30px;
    }

    .left-col {
        order: 2;
        /* Move form to bottom on mobile */
    }

    .right-col {
        order: 1;
        /* Move data to top on mobile */
    }

    .summary-grid {
        grid-template-columns: 1fr;
        /* Stack summary cards */
    }

    header {
        flex-direction: column;
        align-items: flex-start;
        gap: 15px;
    }

    .trip-selector {
        width: 100%;
    }

    .trip-selector select {
        flex: 1;
    }
}

/* Scrollable Members List */
#members-list {
    max-height: 300px;
    overflow-y: auto;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    background: var(--bg-surface);
}

#members-list .list-item {
    padding: 16px;
    margin: 0;
}

#members-list::-webkit-scrollbar {
    width: 8px;
}

#members-list::-webkit-scrollbar-track {
    background: var(--bg-surface);
}

#members-list::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

#members-list::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

/* Scrollable Settlements List */
#settlements-list {
    max-height: 300px;
    overflow-y: auto;
}

#settlements-list::-webkit-scrollbar {
    width: 8px;
}

#settlements-list::-webkit-scrollbar-track {
    background: var(--bg-surface);
}

#settlements-list::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

#settlements-list::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

/* Individual Spending Section - Scrollable */
.individual-spending-section {
    margin-top: 20px;
}

.member-spending-grid {
    display: flex;
    gap: 16px;
    overflow-x: auto;
    overflow-y: hidden;
    padding: 15px 0;
    margin: 0;
    max-width: 100%;
}

.member-spending-grid::-webkit-scrollbar {
    height: 6px;
}

.member-spending-grid::-webkit-scrollbar-track {
    background: var(--bg-elevated);
    border-radius: 3px;
}

.member-spending-grid::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 3px;
}

.member-spending-grid::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

.member-spending-card {
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 18px 20px;
    text-align: center;
    min-width: 160px;
    flex: 1;
    flex-shrink: 0;
}

.member-spending-card .member-name {
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--text-primary);
    margin-bottom: 12px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.member-spending-card .spending-info {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.member-spending-card .spending-row {
    display: flex;
    justify-content: space-between;
    font-size: 0.85rem;
    gap: 12px;
}

.member-spending-card .spending-label {
    color: var(--text-secondary);
}

.member-spending-card .spending-value {
    color: var(--text-primary);
    font-weight: 500;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .member-spending-card {
        min-width: 140px;
        padding: 14px 16px;
    }
}