/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #3498db;
    --secondary-color: #2ecc71;
    --critical-color: #e74c3c;
    --background: #1a1a1a;
    --surface: #2c2c2c;
    --text-primary: #ecf0f1;
    --text-secondary: #95a5a6;
    --border-color: #34495e;
    --timeline-line: #4a5568;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
}

/* Header */
header {
    text-align: center;
    padding: 3rem 2rem;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

header h1 {
    font-size: 3rem;
    margin-bottom: 0.5rem;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

header .subtitle {
    font-size: 1.2rem;
    opacity: 0.9;
}

/* Controls */
.controls {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 1rem;
    padding: 2rem;
    background-color: var(--surface);
}

.filter-btn {
    padding: 0.75rem 1.5rem;
    background-color: var(--background);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
    border-radius: 25px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 0.95rem;
}

.filter-btn:hover {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
    transform: translateY(-2px);
}

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

/* Timeline Container */
.timeline-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 3rem 2rem;
}

.timeline {
    position: relative;
    padding: 2rem 0;
}

/* Timeline Center Line */
.timeline::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 4px;
    height: 100%;
    background: linear-gradient(to bottom, var(--primary-color), var(--secondary-color));
}

/* Year Marker */
.year-marker {
    text-align: center;
    margin: 4rem 0 2rem;
    position: relative;
}

.year-marker h2 {
    display: inline-block;
    background-color: var(--surface);
    padding: 1rem 2rem;
    border-radius: 50px;
    font-size: 2rem;
    border: 3px solid var(--primary-color);
    z-index: 10;
    position: relative;
}

/* Timeline Event */
.timeline-event {
    margin: 2rem 0;
    position: relative;
    opacity: 0;
    animation: fadeInUp 0.6s ease forwards;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.timeline-event.left .event-content {
    margin-right: 55%;
    text-align: right;
}

.timeline-event.right .event-content {
    margin-left: 55%;
}

/* Event Dot */
.event-dot {
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 20px;
    height: 20px;
    background-color: var(--primary-color);
    border: 4px solid var(--background);
    border-radius: 50%;
    z-index: 10;
    cursor: pointer;
    transition: all 0.3s ease;
}

.event-dot.critical {
    background-color: var(--critical-color);
    width: 24px;
    height: 24px;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% {
        box-shadow: 0 0 0 0 rgba(231, 76, 60, 0.7);
    }
    50% {
        box-shadow: 0 0 0 15px rgba(231, 76, 60, 0);
    }
}

.event-dot:hover {
    transform: translateX(-50%) scale(1.3);
}

/* Event Content */
.event-content {
    background-color: var(--surface);
    padding: 1.5rem;
    border-radius: 10px;
    border-left: 4px solid var(--primary-color);
    cursor: pointer;
    transition: all 0.3s ease;
}

.event-content.critical {
    border-left-color: var(--critical-color);
    box-shadow: 0 0 20px rgba(231, 76, 60, 0.2);
}

.event-content:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0,0,0,0.3);
}

.event-date {
    font-size: 0.9rem;
    color: var(--primary-color);
    font-weight: bold;
    margin-bottom: 0.5rem;
}

.event-content.critical .event-date {
    color: var(--critical-color);
}

.event-title {
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
}

.event-description {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.5;
}

.event-tags {
    margin-top: 1rem;
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.tag {
    background-color: var(--primary-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 15px;
    font-size: 0.8rem;
}

.event-category {
    display: inline-block;
    margin-top: 0.5rem;
    padding: 0.25rem 0.75rem;
    background-color: var(--border-color);
    border-radius: 15px;
    font-size: 0.85rem;
}

/* Add Event Button */
.add-event-btn {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    box-shadow: 0 4px 15px rgba(0,0,0,0.3);
    transition: all 0.3s ease;
    z-index: 100;
}

.add-event-btn:hover {
    transform: scale(1.1) rotate(90deg);
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.8);
    animation: fadeIn 0.3s ease;
}

.modal-content {
    background-color: var(--surface);
    margin: 5% auto;
    padding: 2rem;
    border-radius: 15px;
    max-width: 600px;
    position: relative;
    animation: slideIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideIn {
    from { transform: translateY(-50px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

.close, .close-form {
    position: absolute;
    right: 1rem;
    top: 1rem;
    font-size: 2rem;
    cursor: pointer;
    color: var(--text-secondary);
    transition: color 0.3s ease;
}

.close:hover, .close-form:hover {
    color: var(--critical-color);
}

/* Form Styles */
.form-group {
    margin-bottom: 1.5rem;
}

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

.form-group input[type="text"],
.form-group input[type="date"],
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    background-color: var(--background);
    border: 2px solid var(--border-color);
    border-radius: 5px;
    color: var(--text-primary);
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

.form-actions {
    display: flex;
    gap: 1rem;
    justify-content: flex-end;
}

.btn-primary, .btn-secondary {
    padding: 0.75rem 2rem;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1rem;
    transition: all 0.3s ease;
}

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

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

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

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

/* Footer */
footer {
    text-align: center;
    padding: 2rem;
    background-color: var(--surface);
    margin-top: 4rem;
}

.export-btn {
    margin-top: 1rem;
    padding: 0.75rem 2rem;
    background-color: var(--secondary-color);
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.export-btn:hover {
    background-color: #27ae60;
}

/* Responsive Design */
@media (max-width: 768px) {
    .timeline::before {
        left: 30px;
    }
    
    .timeline-event.left .event-content,
    .timeline-event.right .event-content {
        margin-left: 60px;
        margin-right: 0;
        text-align: left;
    }
    
    .event-dot {
        left: 30px;
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    .controls {
        flex-direction: column;
        align-items: stretch;
    }
}