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

:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --success-color: #27ae60;
    --danger-color: #e74c3c;
    --light-bg: #ecf0f1;
    --card-bg: #ffffff;
    --text-color: #2c3e50;
    --border-color: #bdc3c7;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--light-bg);
    color: var(--text-color);
    line-height: 1.6;
    padding-bottom: 2rem;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 1rem;
}

header {
    background-color: var(--primary-color);
    color: white;
    padding: 1.5rem;
    border-radius: 8px;
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow);
}

header h1 {
    margin-bottom: 1rem;
    font-size: 1.8rem;
    text-align: center;
}

nav {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
    flex-wrap: wrap;
}

.nav-btn {
    background-color: rgba(255, 255, 255, 0.2);
    color: white;
    border: none;
    padding: 0.6rem 1.2rem;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.95rem;
    transition: background-color 0.3s;
}

.nav-btn:hover {
    background-color: rgba(255, 255, 255, 0.3);
}

.nav-btn.active {
    background-color: var(--secondary-color);
}

.page {
    display: none;
}

.page.active {
    display: block;
}

.card {
    background-color: var(--card-bg);
    border-radius: 8px;
    padding: 2rem;
    box-shadow: var(--shadow);
}

.card h2 {
    margin-bottom: 1.5rem;
    color: var(--primary-color);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-color);
}

.form-group input[type="time"],
.form-group input[type="date"],
.form-group input[type="number"] {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 1rem;
}

.form-group input[type="time"]:focus,
.form-group input[type="date"]:focus,
.form-group input[type="number"]:focus {
    outline: none;
    border-color: var(--secondary-color);
}

.checkbox-group label {
    display: flex;
    align-items: center;
    cursor: pointer;
}

.checkbox-group input[type="checkbox"] {
    margin-right: 0.5rem;
    width: 18px;
    height: 18px;
    cursor: pointer;
}

.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s;
    display: inline-block;
}

.btn-primary {
    background-color: var(--secondary-color);
    color: white;
}

.btn-primary:hover {
    background-color: #2980b9;
}

.btn-success {
    background-color: var(--success-color);
    color: white;
}

.btn-success:hover {
    background-color: #229954;
}

.btn-danger {
    background-color: var(--danger-color);
    color: white;
}

.btn-danger:hover {
    background-color: #c0392b;
}

.btn-small {
    padding: 0.4rem 0.8rem;
    font-size: 0.85rem;
}

.result {
    margin-top: 2rem;
    padding: 1.5rem;
    background-color: var(--light-bg);
    border-radius: 8px;
}

.result.hidden {
    display: none;
}

.result h3 {
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.result-details p {
    margin-bottom: 0.5rem;
    font-size: 1.1rem;
}

.total-amount {
    font-size: 1.5rem;
    color: var(--success-color);
    font-weight: bold;
}

.breakdown {
    margin: 1.5rem 0;
    padding: 1rem;
    background-color: white;
    border-radius: 4px;
}

.breakdown-item {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
}

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

.history-controls {
    margin-bottom: 1rem;
}

.history-list {
    margin-top: 1.5rem;
}

.history-item {
    background-color: var(--light-bg);
    padding: 1rem;
    border-radius: 4px;
    margin-bottom: 1rem;
}

.history-item-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.history-item-date {
    font-weight: 500;
    color: var(--primary-color);
}

.history-item-total {
    font-size: 1.2rem;
    font-weight: bold;
    color: var(--success-color);
}

.history-item-details {
    font-size: 0.9rem;
    color: #666;
}

.shift-form {
    margin-bottom: 2rem;
    padding-bottom: 2rem;
    border-bottom: 2px solid var(--light-bg);
}

.shifts-list {
    margin-top: 1.5rem;
}

.shift-item {
    background-color: var(--light-bg);
    padding: 1rem;
    border-radius: 4px;
    margin-bottom: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.shift-info {
    flex: 1;
}

.shift-time {
    font-weight: 500;
    color: var(--primary-color);
    margin-bottom: 0.25rem;
}

.shift-rate {
    font-size: 1.2rem;
    color: var(--success-color);
    font-weight: bold;
}

.shift-actions {
    display: flex;
    gap: 0.5rem;
}

.weekday-selector {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.weekday-checkbox {
    display: flex;
    align-items: center;
    padding: 0.5rem 0.75rem;
    background-color: var(--light-bg);
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.2s;
}

.weekday-checkbox:hover {
    background-color: #d5dade;
}

.weekday-checkbox input[type="checkbox"] {
    margin-right: 0.25rem;
}

.empty-state {
    text-align: center;
    padding: 3rem 1rem;
    color: #7f8c8d;
}

.empty-state-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

@media (max-width: 600px) {
    .container {
        padding: 0.5rem;
    }

    header h1 {
        font-size: 1.5rem;
    }

    .card {
        padding: 1.5rem;
    }

    .shift-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }

    .shift-actions {
        width: 100%;
        justify-content: flex-end;
    }
}