:root {
    --primary-color: #2563eb;
    --primary-dark: #1e40af;
    --secondary-color: #64748b;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1);
    --radius: 12px;
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 40px 20px;
}

header {
    text-align: center;
    margin-bottom: 50px;
}

h1 {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--text-main);
    letter-spacing: -0.02em;
    margin-bottom: 10px;
}

.subtitle {
    font-size: 1.1rem;
    color: var(--text-muted);
}

.controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
}

.view-controls {
    display: flex;
    gap: 15px;
}

.btn {
    padding: 10px 20px;
    border-radius: 8px;
    font-weight: 600;
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.2s ease;
    border: none;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

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

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

.btn.secondary {
    background-color: white;
    color: var(--secondary-color);
    border: 1px solid var(--border-color);
}

.btn.secondary:hover {
    background-color: #f1f5f9;
    color: var(--text-main);
}

.btn.download {
    background-color: #10b981; /* Emerald 500 */
    color: white;
}

.btn.download:hover {
    background-color: #059669; /* Emerald 600 */
    box-shadow: 0 4px 6px -1px rgba(16, 185, 129, 0.2);
}

.timeline {
    position: relative;
    padding-left: 40px;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 19px; /* Center of the 40px padding area roughly */
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--border-color);
    border-radius: 2px;
}

.timeline-item {
    margin-bottom: 30px;
    position: relative;
}

.timeline-marker {
    position: absolute;
    left: -40px; /* Adjust based on padding */
    top: 24px;
    width: 40px;
    height: 2px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.timeline-dot {
    width: 16px;
    height: 16px;
    background: white;
    border: 3px solid var(--primary-color);
    border-radius: 50%;
    z-index: 2;
    position: relative;
    left: 20px; /* Center on the line */
}

.timeline-content {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
    transition: box-shadow 0.3s ease, transform 0.2s ease;
}

.timeline-content:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.timeline-header {
    padding: 20px 25px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    background: white;
    border-bottom: 1px solid transparent;
    transition: background-color 0.2s ease;
}

.timeline-header:hover {
    background-color: #f8fafc;
}

.timeline-item.active .timeline-header {
    border-bottom-color: var(--border-color);
}

.timeline-title-group {
    display: flex;
    flex-direction: column;
}

.timeline-title {
    font-size: 1.15rem;
    font-weight: 700;
    color: var(--text-main);
}

.timeline-days {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--primary-color);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 4px;
}

.timeline-body {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s cubic-bezier(0, 1, 0, 1);
    background-color: #fbfbfc;
}

.timeline-item.active .timeline-body {
    max-height: 1000px; /* Arbitrary large height */
    transition: max-height 0.4s ease-in-out;
}

.timeline-body ul {
    padding: 20px 25px 20px 45px;
    list-style-type: disc;
}

.timeline-body li {
    margin-bottom: 8px;
    color: var(--text-main);
    font-size: 0.95rem;
}

.timeline-body li:last-child {
    margin-bottom: 0;
}

.toggle-icon {
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background-color: #f1f5f9;
    color: var(--secondary-color);
    transition: all 0.2s ease;
    font-weight: bold;
    font-size: 1.2rem;
    line-height: 1;
}

.timeline-item.active .toggle-icon {
    transform: rotate(45deg);
    background-color: var(--primary-color);
    color: white;
}

footer {
    margin-top: 60px;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.9rem;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}