:root {
    --primary-color: #3498db;
    --secondary-color: #2c3e50;
    --bg-color: #f4f7f6;
    --card-bg: #ffffff;
    --text-color: #333;
    --border-color: #ddd;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    padding: 0;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    background: var(--card-bg);
    padding: 15px;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

h1 {
    margin: 0;
    font-size: 1.5rem;
    color: var(--secondary-color);
}

#post-creation {
    background: var(--card-bg);
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    margin-bottom: 20px;
}

#post-form textarea {
    width: 100%;
    height: 80px;
    padding: 10px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    resize: vertical;
    font-family: inherit;
}

.form-actions {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 10px;
}

button {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 8px 16px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.9rem;
}

button:hover {
    background-color: #2980b9;
}

.tabs {
    margin-bottom: 15px;
}

.tab-btn {
    background: none;
    color: var(--secondary-color);
    border: 1px solid var(--secondary-color);
    margin-right: 10px;
}

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

/* Timeline Styles */
#timeline-container {
    position: relative;
    padding-left: 20px;
    border-left: 2px solid var(--border-color);
}

.post-card {
    background: var(--card-bg);
    padding: 15px;
    margin-bottom: 15px;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    position: relative;
}

.post-card::before {
    content: '';
    position: absolute;
    left: -26px;
    top: 20px;
    width: 10px;
    height: 10px;
    background: var(--primary-color);
    border-radius: 50%;
    border: 2px solid white;
}

.post-header {
    display: flex;
    justify-content: space-between;
    font-size: 0.85rem;
    color: #777;
    margin-bottom: 8px;
}

.post-user {
    font-weight: bold;
    color: var(--secondary-color);
}

.post-project {
    background: #e8f4f8;
    color: var(--primary-color);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.8rem;
}

.post-content {
    font-size: 1rem;
    line-height: 1.5;
}

.post-tags {
    margin-top: 8px;
    font-size: 0.85rem;
    color: var(--primary-color);
}

/* Overlay */
.overlay {
    display: none;
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(0,0,0,0.5);
    justify-content: center;
    align-items: center;
}

.modal {
    background: white;
    padding: 30px;
    border-radius: 8px;
    width: 300px;
    text-align: center;
}

.modal input {
    width: 100%;
    padding: 8px;
    margin-bottom: 10px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
}

.project-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.project-card {
    background: white;
    border-radius: 8px;
    padding: 20px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.project-card h3 {
    margin-top: 0;
    color: var(--primary-color);
}

.project-card .role-badge {
    display: inline-block;
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 0.8em;
    margin-bottom: 10px;
}

.role-owner {
    background-color: #ffd700;
    color: #333;
}

.role-member {
    background-color: #e0e0e0;
    color: #333;
}

.nav-link {
    margin-right: 15px;
    color: var(--primary-color);
    text-decoration: none;
    font-weight: bold;
}

.nav-link:hover {
    text-decoration: underline;
}