/* --- CSS Variables & Reset --- */
:root {
    --bg-color: #f0f2f5;
    --text-color: #050505;
    --secondary-text: #65676b;
    --primary-color: #1877f2; /* FB Blue */
    --card-bg: #ffffff;
    --nav-height: 60px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    padding-top: var(--nav-height);
}

/* --- Utilities --- */
.text-primary { color: var(--primary-color); }
.red { color: #f3425f; }
.green { color: #45bd62; }
img { max-width: 100%; }

/* --- NAVBAR STYLES --- */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--nav-height);
    background-color: var(--card-bg);
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    z-index: 100;
}

.nav-left, .nav-middle, .nav-right {
    display: flex;
    align-items: center;
}

.logo { font-size: 40px; margin-right: 10px;}

.search-box {
    background-color: var(--bg-color);
    padding: 10px 20px;
    border-radius: 20px;
    display: flex;
    align-items: center;
}
.search-box input {
    background: transparent;
    border: none;
    outline: none;
    margin-left: 10px;
    font-size: 15px;
}

.nav-middle { flex: 1; justify-content: center; }

.nav-tab {
    padding: 10px 30px;
    font-size: 22px;
    color: var(--secondary-text);
    cursor: pointer;
    border-bottom: 3px solid transparent;
}
.nav-tab.active {
    color: var(--primary-color);
    border-bottom: 3px solid var(--primary-color);
}
.nav-tab:hover:not(.active) {
    background-color: var(--bg-color);
    border-radius: 8px;
}

.nav-right { gap: 10px; }
.nav-icon {
    width: 40px; height: 40px;
    background-color: var(--bg-color);
    border-radius: 50%;
    display: flex; justify-content: center; align-items: center;
    font-size: 18px;
    cursor: pointer;
}
.nav-profile-img {
    width: 40px; height: 40px;
    border-radius: 50%;
    cursor: pointer;
}

/* --- MAIN LAYOUT GRID --- */
.main-container {
    display: grid;
    /* The classic 1/4 - 1/2 - 1/4 layout ratio */
    grid-template-columns: 1fr 2fr 1fr;
    gap: 25px;
    max-width: 1200px;
    margin: 20px auto;
    padding: 0 20px;
}

/* Make Sidebars "Sticky" so they stay put while feed scrolls */
.left-sidebar, .right-sidebar {
    position: sticky;
    top: calc(var(--nav-height) + 20px);
    height: calc(100vh - var(--nav-height) - 40px);
    overflow-y: auto;
}

@media (max-width: 900px) {
    .main-container { grid-template-columns: 1fr; }
    .left-sidebar, .right-sidebar, .nav-middle { display: none; }
}


/* --- COMPONENTS STYLES --- */

/* Generic Card Style */
.card {
    background-color: var(--card-bg);
    border-radius: 8px;
    box-shadow: 0 1px 2px rgba(0,0,0,0.1);
    padding: 15px;
    margin-bottom: 20px;
}

/* Sidebar Items */
.sidebar-menu-item {
    display: flex; align-items: center;
    padding: 10px;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
}
.sidebar-menu-item:hover { background-color: #e4e6e9; }
.sidebar-menu-item img {
    width: 35px; height: 35px; border-radius: 50%; margin-right: 15px;
}
.icon-large { font-size: 24px; margin-right: 15px; width: 35px; text-align: center;}

/* Create Post Box */
.create-input-row { display: flex; align-items: center; margin-bottom: 15px; }
.create-input-row img { width: 40px; height: 40px; border-radius: 50%; margin-right: 10px;}
.create-input-row input {
    flex: 1;
    background-color: var(--bg-color);
    border: none; outline: none;
    padding: 12px 20px;
    border-radius: 20px;
    font-size: 16px;
}
.create-actions { display: flex; justify-content: space-between; margin-top: 15px;}
.action-item {
    flex: 1; display: flex; justify-content: center; align-items: center;
    padding: 8px; border-radius: 8px; cursor: pointer; font-weight: 600; color: var(--secondary-text);
}
.action-item:hover { background-color: var(--bg-color); }
.action-item i { margin-right: 8px; font-size: 20px; }

.post-submit-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 8px 25px;
    border-radius: 6px;
    font-weight: bold;
    cursor: pointer;
}
.post-submit-btn:hover { background-color: #1567d3; }


/* Post Styles */
.post-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 15px;}
.post-author-info { display: flex; align-items: center; }
.post-author-info img { width: 40px; height: 40px; border-radius: 50%; margin-right: 10px; }
.author-name { font-size: 16px; margin-bottom: 3px; }
.timestamp { font-size: 13px; color: var(--secondary-text); }
.post-content p { font-size: 15px; margin-bottom: 15px; }
.post-img { width: 100%; border-radius: 8px; }
.post-stats {
    display: flex; justify-content: space-between;
    color: var(--secondary-text); font-size: 14px;
    padding: 10px 0;
}
.post-actions-row { display: flex; justify-content: space-around; margin-top: 5px; }
.action-btn {
    flex: 1; display: flex; justify-content: center; align-items: center;
    padding: 8px; border-radius: 6px; cursor: pointer;
    color: var(--secondary-text); font-weight: 600;
}
.action-btn:hover { background-color: var(--bg-color); }
.action-btn .icon { margin-right: 8px; font-size: 18px; }

/* JS Interaction Styles for Like Button */
.liked {
    color: var(--primary-color) !important;
}

/* Right Sidebar Contacts */
.contact-item {
    display: flex; align-items: center;
    padding: 10px; border-radius: 8px; cursor: pointer;
}
.contact-item:hover { background-color: #e4e6e9; }
.contact-img-wrap { position: relative; margin-right: 15px;}
.contact-img-wrap img { width: 35px; height: 35px; border-radius: 50%; }
.online::after {
    content: '';
    position: absolute;
    bottom: 0; right: 0;
    width: 10px; height: 10px;
    background-color: #31a24c;
    border: 2px solid var(--card-bg);
    border-radius: 50%;
}