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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #121212;
    color: #888;
    margin: 0;
    display: flex;
    flex-direction: column;
    height: 100vh;
    overflow: auto;
}

.container {
    display: flex;
    width: 100%;
    flex: 1;
}

.participants-panel, .right-panel, .left-panel {
    background-color: #1e1e1e;
    border-radius: 12px;
    padding: 20px;
    box-shadow: 0 2px 15px rgba(0, 0, 0, 0.3);
    margin: 10px;
}

.participants-panel {
    width: 15%;
    display: flex;
    flex-direction: column;
    overflow-y: auto;
    max-height: 400px;
}

.left-panel {
    width: 20%;
}

.main-content {
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
    background-color: #1e1e1e;
    border-radius: 12px;
    box-shadow: 0 2px 15px rgba(0, 0, 0, 0.3);
    overflow-y: auto;
}

h2, h3 {
    margin: 0;
    font-weight: 600;
    color: #e0e0e0;
    text-align: left;
}

h3 {
    font-size: 1.3em;
}

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

.add-expense-btn,
.add-activity-btn,
.back-btn,
.delete-btn {
    padding: 6px 12px;
    font-size: 1em;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.add-expense-btn,
.add-activity-btn,
.back-btn {
    background-color: #bb86fc;
    color: white;
}

.add-expense-btn:hover,
.add-activity-btn:hover,
.back-btn:hover {
    background-color: #8856f0;
}

.delete-btn {
    background-color: #dc3545;
    color: white;
    padding: 6px 12px;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.delete-btn:hover {
    background-color: #c82333;
}

.balance-item {
    background-color: #1e1e1e;
    padding: 10px;
    border-radius: 8px;
    box-shadow: 0 1px 5px rgba(0, 0, 0, 0.2);
    margin-bottom: 15px;
}

.activity-item, .participant-item {
    background-color: #1e1e1e;
    padding: 12px;
    border-radius: 8px;
    box-shadow: 0 1px 10px rgba(0, 0, 0, 0.2);
    margin-bottom: 10px;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.2s;
}

.activity-item:hover, .participant-item:hover {
    background-color: #2a2a2a;
    transform: translateY(-2px);
}

.activity-item.active {
    outline: 2px solid #bb86fc;
    background-color: #1e1e1e;
    color: #bb86fc;
}

.participant-item {
    padding: 10px;
    margin-bottom: 10px;
    font-size: 0.95em;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.main-content::-webkit-scrollbar,
.participants-panel::-webkit-scrollbar,
.left-panel::-webkit-scrollbar {
    width: 8px;
}

.main-content::-webkit-scrollbar-thumb,
.participants-panel::-webkit-scrollbar-thumb,
.left-panel::-webkit-scrollbar-thumb {
    background-color: #555;
    border-radius: 10px;
}

.scrollbar-color {
    scrollbar-width: thin;
    scrollbar-color: #555 #2a2a2a;
}

.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    justify-content: center;
    align-items: center;
    visibility: hidden;
    opacity: 0;
    transition: visibility 0s, opacity 0.3s;
}

.modal.active {
    visibility: visible;
    opacity: 1;
}

.modal-content {
    background: #2a2a2a;
    padding: 20px;
    border-radius: 10px;
    width: 400px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.5);
}

.modal-content h3 {
    margin-bottom: 20px;
    color: #e0e0e0;
}

.modal-content input,
.modal-content select,
.modal-content button {
    width: 100%;
    padding: 10px;
    margin-bottom: 10px;
    border-radius: 5px;
    border: 1px solid #444;
    background-color: #1e1e1e;
    color: #e0e0e0;
}

.modal-content button {
    background-color: #bb86fc;
    color: white;
    border: none;
    cursor: pointer;
}

.modal-content button:hover {
    background-color: #8856f0;
}

.expense-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 10px;
}

.expense-table th,
.user-input-table th,
.transaction-table th,
.balance-table th {
    padding: 12px;
    text-align: left;
    border: 1px solid #444;
    font-size: 0.9em;
}

.expense-table td,
.user-input-table td,
.transaction-table td,
.balance-table td {
    padding: 12px;
    text-align: left;
    border: 1px solid #444;
    font-size: 0.8em;
}

.expense-table th {
    background-color: #3a3a3a;
    font-weight: bold;
    color: #e0e0e0;
}

.expense-table td:nth-child(4) {
    text-align: right;
}

.expense-table tr:nth-child(even) {
    background-color: #2a2a2a;
}

.expense-table tr:hover {
    background-color: #3a3a3a;
}

.user-input-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 10px;
}

.user-input-table th {
    background-color: #3a3a3a;
    font-weight: bold;
    color: #e0e0e0;
}

.user-input-table tr:nth-child(even) {
    background-color: #2a2a2a;
}

input[type="number"]::-webkit-inner-spin-button,
input[type="number"]::-webkit-outer-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

input[type="number"] {
    -moz-appearance: textfield;
}

.member-list, .user-list {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.member-button, .user-button {
    padding: 6px 12px;
    background-color: #1e1e1e;
    border: 1px solid #555;
    color: #e0e0e0;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s ease, color 0.3s ease;
    font-size: 1em;
    margin-bottom: 10px;
    display: inline-block;
}

.member-button:hover, .user-button:hover {
    background-color: #555;
    color: #fff;
}

.member-button.remove {
    border: 1px solid #dc3545;
    color: #dc3545;
}

.member-button.remove:hover {
    background-color: #dc3545;
    color: white;
}

.transaction-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 10px;
}

.transaction-table th {
    background-color: #3a3a3a;
    font-weight: bold;
    color: #e0e0e0;
}

.transaction-table tr:nth-child(even) {
    background-color: #2a2a2a;
}

.transaction-table tr:hover {
    background-color: #3a3a3a;
}

.balance-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 10px;
}

.balance-table th {
    background-color: #3a3a3a;
    font-weight: bold;
    color: #e0e0e0;
}

.balance-table tr:nth-child(even) {
    background-color: #2a2a2a;
}

.balance-table tr:hover {
    background-color: #3a3a3a;
}

.right-align {
    text-align: right;
}

.negative {
    color: red;
}

.positive {
    color: green;
}

.transaction-table td.right-align {
    text-align: right;
}

.balance-table td.right-align {
    text-align: right;
}

.back-btn {
    padding: 6px 12px;
    border-radius: 8px;
    background-color: #5954c2;
    border: none;
    color: white;
    font-size: .7em;
    cursor: pointer;
    transition: background-color 0.3s ease;
    float: right;
}

.back-btn:hover {
    background-color: #8856f0;
}