:root {
    --primary-color: #4a90e2;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --warning-color: #ffc107;
    --neutral-color: #6c757d;
    --bg-color: #f8f9fa;
    --text-color: #333;
    --border-color: #dee2e6;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 20px;
}

h1 {
    text-align: center;
    margin-bottom: 40px;
    color: var(--primary-color);
    font-size: 2rem;
}

.timeline-loading {
    text-align: center;
    padding: 40px;
    color: var(--neutral-color);
    font-size: 1.2rem;
}

.timeline {
    position: relative;
    padding: 20px 0;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    top: 0;
    bottom: 0;
    width: 3px;
    background: var(--primary-color);
}

.date-group {
    margin-bottom: 60px;
}

.date-marker {
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 30px;
}

.date-marker h2 {
    background: var(--primary-color);
    color: white;
    padding: 10px 30px;
    border-radius: 25px;
    font-size: 1.2rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.session-item {
    position: relative;
    width: 45%;
    margin-bottom: 40px;
}

.session-item::before {
    content: '';
    position: absolute;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    border: 4px solid white;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
    top: 0;
}

.session-item:nth-child(odd) {
    margin-left: 0;
    text-align: right;
}

.session-item:nth-child(odd)::before {
    right: -58px;
}

.session-item:nth-child(odd) .session-card {
    margin-right: 0;
}

.session-item:nth-child(even) {
    margin-left: auto;
}

.session-item:nth-child(even)::before {
    left: -58px;
}

.session-card {
    background: white;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 3px 10px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s, box-shadow 0.3s;
}

.session-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.15);
}

.session-time {
    font-size: 0.85rem;
    color: var(--neutral-color);
    margin-bottom: 8px;
}

.session-role {
    font-size: 1.1rem;
    font-weight: bold;
    margin-bottom: 8px;
    color: var(--primary-color);
}

.session-duration {
    font-size: 0.9rem;
    margin-bottom: 8px;
    color: var(--text-color);
}

.session-status {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 0.85rem;
    font-weight: 600;
}

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

.status-unproductive {
    background: var(--neutral-color);
    color: white;
}

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

.status-timeout {
    background: var(--warning-color);
    color: #333;
}

@media (max-width: 768px) {
    .timeline::before {
        left: 30px;
    }

    .session-item {
        width: calc(100% - 60px);
        margin-left: 60px !important;
        text-align: left !important;
    }

    .session-item::before {
        left: -48px !important;
    }

    .session-item:nth-child(odd) .session-card,
    .session-item:nth-child(even) .session-card {
        margin-right: 0;
    }

    .date-marker h2 {
        font-size: 1rem;
        padding: 8px 20px;
    }

    h1 {
        font-size: 1.5rem;
    }
}