/* ==========================================
   1. CSS Reset & Variables
   ========================================== */
:root {
    --primary-color: #4f46e5;
    --primary-hover: #4338ca;
    --success-color: #10b981;
    --success-hover: #059669;
    --bg-color: #f3f4f6;
    --card-bg: #ffffff;
    --text-main: #1f2937;
    --text-muted: #6b7280;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --radius: 8px;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.5;
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

/* ==========================================
   2. Layout & Containers
   ========================================== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.main-content {
    padding: 30px 0;
}

/* ==========================================
   3. Buttons & Elements
   ========================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 18px;
    font-size: 0.95rem;
    font-weight: 600;
    border-radius: var(--radius);
    border: none;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
}

.btn:active {
    transform: scale(0.98);
}

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

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

.btn-success {
    background-color: var(--success-color);
    color: #ffffff;
}

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

.btn-outline {
    background-color: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-main);
}

.btn-outline:hover {
    background-color: var(--border-color);
}

/* ==========================================
   4. Forms & Inputs
   ========================================== */
.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 6px;
    font-weight: 500;
    font-size: 0.9rem;
    color: var(--text-main);
}

.form-control {
    width: 100%;
    padding: 12px 15px;
    font-size: 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    background-color: #fff;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.15);
}

/* ==========================================
   5. Navbar & Header
   ========================================== */
.navbar {
    background-color: #ffffff;
    border-bottom: 1px solid var(--border-color);
    padding: 15px 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary-color);
}

.nav-links {
    display: flex;
    gap: 20px;
    align-items: center;
}

/* ==========================================
   6. Post Cards & Grid Feed
   ========================================== */
.posts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 24px;
}

.post-card {
    background-color: var(--card-bg);
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: transform 0.2s, box-shadow 0.2s;
    display: flex;
    flex-direction: column;
}

.post-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.post-image-container {
    width: 100%;
    height: 180px;
    background-color: var(--border-color);
    overflow: hidden;
}

.post-image-container img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.post-body {
    padding: 16px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.post-category {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 6px;
}

.post-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-main);
}

.post-description {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 16px;
    flex: 1;
}

.post-actions {
    display: flex;
    gap: 10px;
    border-top: 1px solid var(--border-color);
    padding-top: 12px;
}

.post-actions .btn {
    flex: 1;
    padding: 8px 12px;
    font-size: 0.85rem;
}

/* ==========================================
   7. Modal Window Styling
   ========================================== */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s;
}

.modal-overlay.active {
    opacity: 1;
    visibility: visible;
}

.modal-container {
    background-color: #ffffff;
    width: 100%;
    max-width: 500px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
    padding: 24px;
    max-height: 90vh;
    overflow-y: auto;
    transform: translateY(20px);
    transition: transform 0.3s;
}

.modal-overlay.active .modal-container {
    transform: translateY(0);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.modal-close-btn {
    background: none;
    border: none;
    font-size: 1.25rem;
    cursor: pointer;
    color: var(--text-muted);
}

.modal-close-btn:hover {
    color: var(--text-main);
}

/* ==========================================
   8. Chat Interface Layout
   ========================================== */
.chat-wrapper {
    display: grid;
    grid-template-columns: 300px 1fr;
    background: #ffffff;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    height: 75vh;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.chat-sidebar {
    border-right: 1px solid var(--border-color);
    overflow-y: auto;
    background-color: #f9fafb;
}

.chat-main-area {
    display: flex;
    flex-direction: column;
    background-color: #ffffff;
}

.chat-messages {
    flex: 1;
    padding: 20px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.message-bubble {
    max-width: 70%;
    padding: 10px 14px;
    border-radius: var(--radius);
    font-size: 0.95rem;
}

.message-bubble.incoming {
    background-color: var(--bg-color);
    color: var(--text-main);
    align-self: flex-start;
}

.message-bubble.outgoing {
    background-color: var(--primary-color);
    color: #ffffff;
    align-self: flex-end;
}

.chat-input-form {
    display: flex;
    padding: 15px;
    border-top: 1px solid var(--border-color);
    gap: 10px;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .chat-wrapper {
        grid-template-columns: 1fr;
    }
    .chat-sidebar {
        display: none; /* Can be toggled with a mobile back button */
    }
}