:root {
    --primary-color: #007bff;
    --secondary-color: #28a745;
    --tertiary-color: #dc3545;
    --background-color: #f8f9fa;
    --card-color: #ffffff;
    --text-color: #343a40;
    --border-color: #e0e0e0;
    --box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

body {
    font-family: 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    padding: 2rem;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
}

.container {
    background-color: var(--card-color);
    border-radius: 16px;
    box-shadow: var(--box-shadow);
    padding: 2.5rem;
    max-width: 800px;
    width: 100%;
    text-align: center;
    transition: transform 0.3s ease;
}

.container:hover {
    transform: translateY(-5px);
}

h1 {
    color: var(--primary-color);
    font-weight: 700;
    font-size: 2.2rem;
    margin-bottom: 2rem;
}

.user-selection {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-bottom: 2.5rem;
}

.user-btn {
    padding: 1rem 3rem;
    font-size: 1.25rem;
    font-weight: 600;
    border: 2px solid var(--primary-color);
    border-radius: 10px;
    background-color: transparent;
    color: var(--primary-color);
    cursor: pointer;
    transition: all 0.3s ease;
}

.user-btn:hover {
    background-color: var(--primary-color);
    color: #fff;
    transform: scale(1.05);
}

.hidden {
    display: none;
}

#current-user {
    color: var(--primary-color);
    font-size: 1.75rem;
    margin-bottom: 2rem;
}

.time-controls {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 1.2rem;
    margin-bottom: 2.5rem;
}

.control-btn {
    padding: 0.9rem 1.8rem;
    font-size: 1.1rem;
    font-weight: 600;
    border: none;
    border-radius: 8px;
    color: #fff;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.2s ease;
}

.control-btn:hover {
    transform: translateY(-2px);
}

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

.primary-btn:hover {
    background-color: #0056b3;
}

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

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

.pause-btn {
    background-color: transparent;
    border: 2px solid var(--secondary-color);
    color: var(--secondary-color);
}

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

.time-summary-container {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    margin-bottom: 3rem;
}

.time-summary {
    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
    gap: 1.5rem;
}

.summary-item {
    background-color: var(--background-color);
    padding: 1.5rem;
    border-radius: 10px;
    flex: 1;
    min-width: 150px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.summary-item p {
    margin: 0;
    font-size: 1rem;
    color: #6c757d;
    font-weight: 500;
}

.time-display {
    display: block;
    font-size: 1.8rem;
    font-weight: 700;
    margin-top: 0.5rem;
}

#start-time {
    color: var(--primary-color);
}

#end-time {
    color: var(--primary-color);
}

#pause-duration {
    color: var(--secondary-color);
}

.total-duration-box {
    background-color: var(--primary-color);
    color: white;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
}

.total-duration-box p {
    font-size: 1.2rem;
    margin: 0;
    font-weight: 500;
}

.total-duration-box .time-display {
    color: white;
    font-size: 3rem;
    font-weight: 700;
    margin-top: 0.5rem;
}

.history {
    text-align: left;
}

.history h3 {
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 0.5rem;
    margin-bottom: 1.5rem;
    color: var(--text-color);
}

.history-controls {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1.5rem;
    margin-bottom: 1rem;
}

.history-controls button {
    background-color: var(--background-color);
    border: 1px solid var(--border-color);
    color: var(--text-color);
    padding: 0.5rem 1rem;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1.2rem;
    transition: background-color 0.3s;
}

.history-controls button:hover {
    background-color: #e9ecef;
}

#current-month-display {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--primary-color);
}

.table-container {
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
    background-color: var(--card-color);
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

th, td {
    padding: 1rem;
    text-align: center;
    border: 1px solid var(--border-color);
}

thead {
    background-color: #e9ecef;
    font-weight: 600;
}

tbody tr:nth-child(even) {
    background-color: var(--background-color);
}

.pause-time {
    color: var(--secondary-color);
    font-weight: bold;
}

.total-time {
    color: var(--primary-color);
    font-weight: bold;
}