:root {
    --primary-color: #4a90e2;
    --primary-dark: #357abd;
    --background-color: #f0f2f5;
    --surface-color: #ffffff;
    --text-color: #333;
    --border-color: #e1e8ed;
    --success-color: #2e7d32;
    --error-color: #c62828;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    margin: 0;
    background-color: var(--background-color);
    color: var(--text-color);
}

header {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem 2rem;
    text-align: center;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.container {
    display: grid;
    grid-template-columns: 300px 1fr 350px;
    gap: 1.5rem;
    padding: 1.5rem;
    max-width: 1600px;
    margin: auto;
}

.card {
    background-color: var(--surface-color);
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

#left-panel,
#center-panel {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

#right-panel {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

h2 {
    color: var(--primary-color);
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 0.5rem;
    margin-top: 0;
    font-size: 1.25rem;
}

/* Forms & Inputs */
.inline-form {
    display: flex;
    gap: 0.5rem;
}

.inline-form input {
    flex-grow: 1;
}

.inline-form button {
    flex-shrink: 0;
    width: 45px;
}

form {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.form-control {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

input[type="text"],
input[type="number"],
select {
    padding: 0.75rem;
    border: 1px solid #ccc;
    border-radius: 4px;
    box-sizing: border-box;
    width: 100%;
}

input:focus,
select:focus {
    outline: 2px solid var(--primary-color);
    border-color: var(--primary-color);
}

button {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0.75rem;
    border-radius: 4px;
    cursor: pointer;
    font-weight: bold;
    transition: background-color 0.2s;
}

button:hover {
    background-color: var(--primary-dark);
}

button:disabled {
    background-color: #a0c3e8;
    cursor: not-allowed;
}

fieldset {
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 0.5rem 1rem;
}

legend {
    padding: 0 0.5rem;
    color: #555;
}

.radio-group {
    display: flex;
    justify-content: space-around;
}

/* Lists */
ul {
    list-style-type: none;
    padding: 0;
    margin: 0;
}

#groups-list li,
#members-list li {
    padding: 0.75rem;
    cursor: pointer;
    border-radius: 4px;
    margin-bottom: 0.5rem;
    transition: background-color 0.2s;
    word-break: break-all;
    display: grid;
    grid-template-columns: auto 1fr;
    align-items: center;
    gap: 0.5rem;
}

#groups-list li.selected {
    background-color: var(--primary-color);
    color: white;
    font-weight: bold;
}

#groups-list li:not(.selected):hover {
    background-color: #e9ecef;
}

#expenses-list li {
    padding: 0.75rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

#expenses-list li:last-child {
    border-bottom: none;
}

.expense-actions button {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    padding: 0.2rem;
    color: var(--error-color);
}

/* Right Panel */
#balances-list div,
#settlements-list div {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

#balances-list div:last-child,
#settlements-list div:last-child {
    border-bottom: none;
}

.positive {
    color: var(--success-color);
    font-weight: bold;
}

.negative {
    color: var(--error-color);
    font-weight: bold;
}

/* Action Buttons */
.action-buttons {
    display: flex;
    gap: 0.5rem;
    margin-left: auto;
}

.action-button {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 0.9rem;
    padding: 0.3rem;
    border-radius: 3px;
    transition: background-color 0.2s;
}

.edit-button {
    color: var(--primary-color);
}

.edit-button:hover {
    background-color: rgba(74, 144, 226, 0.1);
}

.delete-button {
    color: var(--error-color);
}

.delete-button:hover {
    background-color: rgba(198, 40, 40, 0.1);
}

/* Modal Styles */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
}

.modal-content {
    background-color: var(--surface-color);
    margin: 15% auto;
    padding: 2rem;
    border-radius: 8px;
    width: 90%;
    max-width: 400px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.modal-actions {
    display: flex;
    justify-content: flex-end;
    gap: 1rem;
    margin-top: 1.5rem;
}

.modal-actions button {
    padding: 0.5rem 1rem;
}

#rename-cancel {
    background-color: #6c757d;
}

#rename-cancel:hover {
    background-color: #5a6268;
}

/* Split type input styles */
#dynamic-split-inputs h4 {
    margin: 0 0 1rem 0;
    color: var(--primary-color);
    font-size: 1rem;
}

#dynamic-split-inputs .form-control {
    margin-bottom: 0.5rem;
}

#dynamic-split-inputs input {
    margin-top: 0.25rem;
}

.exact-input, .percent-input {
    width: 100%;
    padding: 0.5rem;
    border: 1px solid #ccc;
    border-radius: 4px;
    box-sizing: border-box;
}

.exact-input:focus, .percent-input:focus {
    outline: 2px solid var(--primary-color);
    border-color: var(--primary-color);
}

/* Responsive Design */
@media (max-width: 1200px) {
    .container {
        grid-template-columns: 250px 1fr 300px;
    }
}

@media (max-width: 992px) {
    .container {
        grid-template-columns: 1fr 1fr;
    }

    #left-panel {
        grid-row: 1 / 2;
    }

    #center-panel {
        grid-row: 1 / 2;
    }

    #right-panel {
        grid-column: 1 / 3;
        grid-row: 2 / 3;
    }
}

@media (max-width: 768px) {
    .container {
        grid-template-columns: 1fr;
    }

    #right-panel {
        grid-column: auto;
        grid-row: auto;
    }
}