:root {
    --bg-primary: #f5f7fa;
    --bg-secondary: #ffffff;
    --text-primary: #2d3748;
    --text-secondary: #4a5568;
    --accent-blue: #4299e1;
    --accent-purple: #9f7aea;
    --accent-pink: #ed64a6;
    --glass-bg: rgba(255, 255, 255, 0.7);
    --glass-border: 1px solid rgba(255, 255, 255, 0.3);
    --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    --hover-scale: 1.02;
    --transition-speed: 0.3s;
}

[data-theme="dark"] {
    --bg-primary: #1a202c;
    --bg-secondary: #2d3748;
    --text-primary: #e2e8f0;
    --text-secondary: #cbd5e0;
    --accent-blue: #63b3ed;
    --accent-purple: #b794f4;
    --accent-pink: #fbb6ce;
    --glass-bg: rgba(45, 55, 72, 0.6);
    --glass-border: 1px solid rgba(255, 255, 255, 0.1);
    --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

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

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Glassmorphism Base */
.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: var(--glass-border);
    border-radius: 16px;
    box-shadow: var(--glass-shadow);
    transition: all var(--transition-speed) ease;
    position: relative;
    overflow: hidden;
}

.glass-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
}

.glass-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--glass-shadow), 0 12px 40px rgba(0,0,0,0.15);
}

/* Header Styles */
.glass-header {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: var(--glass-border);
    border-radius: 20px;
    margin-bottom: 2rem;
    padding: 1.5rem;
    box-shadow: var(--glass-shadow);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.header-content h1 {
    font-size: 2.2rem;
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-link {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    transition: all var(--transition-speed);
    display: inline-flex;
    align-items: center;
}

.nav-link:hover {
    background: rgba(0,0,0,0.05);
    color: var(--accent-blue);
}

.nav-link.active {
    background: var(--accent-blue);
    color: white;
}

.theme-btn {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    border: var(--glass-border);
    border-radius: 12px;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-speed);
}

.theme-btn:hover {
    background: rgba(255,255,255,0.2);
    transform: rotate(15deg);
}

.theme-icon {
    font-size: 1.2rem;
}

/* Create Post Section */
.create-post h2 {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.create-post h2::before {
    content: "✨";
    font-size: 1.2rem;
}

#post-form {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

#post-content {
    min-height: 120px;
    padding: 1rem;
    border: none;
    border-radius: 12px;
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    color: var(--text-primary);
    font-size: 1rem;
    resize: vertical;
    transition: all var(--transition-speed);
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.05);
}

#post-content:focus {
    outline: none;
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.05), 0 0 0 2px var(--accent-blue);
    background: rgba(255,255,255,0.8);
}

.form-footer {
    display: flex;
    justify-content: flex-end;
}

.post-btn {
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
    color: white;
    border: none;
    padding: 0.75rem 2rem;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-speed);
    box-shadow: 0 4px 15px rgba(66, 153, 225, 0.3);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.post-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(66, 153, 225, 0.4);
}

.post-btn:active {
    transform: translateY(0);
}

/* Feed Section */
.feed {
    margin-bottom: 2rem;
}

.post {
    padding: 1.5rem;
    border-bottom: 1px solid rgba(255,255,255,0.1);
    transition: background var(--transition-speed);
}

.post:last-child {
    border-bottom: none;
}

.post:hover {
    background: rgba(255,255,255,0.05);
}

.post-header {
    display: flex;
    align-items: center;
    margin-bottom: 1rem;
    gap: 1rem;
}

.post-avatar {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 600;
    font-size: 1.2rem;
    flex-shrink: 0;
}

.post-author {
    flex-grow: 1;
}

.post-author h3 {
    margin: 0 0 0.25rem 0;
    font-size: 1.1rem;
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

.post-time {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.post-content {
    margin-bottom: 1.5rem;
    line-height: 1.6;
    color: var(--text-primary);
    font-size: 1rem;
}

.post-actions {
    display: flex;
    gap: 1.5rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.post-actions button {
    background: none;
    border: none;
    color: inherit;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.3rem;
    padding: 0.3rem 0.5rem;
    border-radius: 8px;
    transition: all var(--transition-speed);
}

.post-actions button:hover {
    background: rgba(255,255,255,0.1);
    color: var(--accent-blue);
    transform: scale(1.05);
}

.likes-count {
    font-weight: 600;
    color: var(--accent-pink);
}

.comments-count {
    font-weight: 600;
}

/* Profile Page Styles */
.profile-header {
    display: flex;
    align-items: center;
    gap: 2rem;
    margin-bottom: 2rem;
}

.profile-avatar img {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    object-fit: cover;
    border: 3px solid var(--accent-blue);
    box-shadow: 0 4px 15px rgba(66, 153, 225, 0.3);
}

.profile-info h2 {
    margin-bottom: 0.5rem;
    font-size: 1.8rem;
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.profile-bio {
    margin-bottom: 1.5rem;
    line-height: 1.6;
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.stats {
    display: flex;
    gap: 2rem;
    font-size: 0.95rem;
    color: var(--text-secondary);
}

.stats span {
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.3rem;
}

.stats span::before {
    content: "●";
    font-size: 0.6rem;
}

.edit-profile h3,
.user-posts h2 {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.edit-profile h3::before,
.user-posts h2::before {
    content: "📝";
    font-size: 1.2rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

#bio {
    width: 100%;
    min-height: 100px;
    padding: 1rem;
    border: none;
    border-radius: 12px;
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    color: var(--text-primary);
    resize: vertical;
    transition: all var(--transition-speed);
}

#bio:focus {
    outline: none;
    box-shadow: 0 0 0 2px var(--accent-blue);
    background: rgba(255,255,255,0.8);
}

.save-btn {
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
    color: white;
    border: none;
    padding: 0.75rem 2rem;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-speed);
    box-shadow: 0 4px 15px rgba(66, 153, 225, 0.3);
    width: 100%;
    max-width: 200px;
}

.save-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(66, 153, 225, 0.4);
}

.save-btn:active {
    transform: translateY(0);
}

.user-posts h2 {
    margin-top: 2rem;
}

/* Comments Section */
.comments-section {
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid rgba(255,255,255,0.1);
}

.comments-list {
    margin-bottom: 1rem;
    max-height: 200px;
    overflow-y: auto;
}

.comment {
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    padding: 0.75rem;
    background: rgba(255,255,255,0.05);
    border-radius: 10px;
    margin-bottom: 0.5rem;
}

.comment-avatar {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    background: var(--accent-purple);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    flex-shrink: 0;
}

.comment-content {
    flex-grow: 1;
}

.comment-content strong {
    color: var(--text-primary);
}

.comment-form {
    display: flex;
    gap: 0.5rem;
}

.comment-input {
    flex-grow: 1;
    padding: 0.75rem;
    border: none;
    border-radius: 10px;
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    color: var(--text-primary);
}

.comment-input:focus {
    outline: none;
    box-shadow: 0 0 0 2px var(--accent-blue);
}

.comment-input::placeholder {
    color: var(--text-secondary);
}

.comment-form button {
    background: var(--accent-blue);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 10px;
    cursor: pointer;
    transition: all var(--transition-speed);
}

.comment-form button:hover {
    background: var(--accent-purple);
    transform: translateY(-2px);
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 0 0.5rem;
    }

    .header-content {
        flex-direction: column;
        text-align: center;
    }

    .profile-header {
        flex-direction: column;
        text-align: center;
    }

    .stats {
        justify-content: center;
        margin-top: 1rem;
        flex-wrap: wrap;
    }

    .post-actions {
        flex-wrap: wrap;
    }

    .comment {
        flex-direction: column;
        align-items: flex-start;
    }

    .comment-avatar {
        align-self: flex-start;
    }
}

@media (max-width: 480px) {
    .nav-link,
    .theme-btn {
        padding: 0.4rem 0.8rem;
        font-size: 0.9rem;
    }

    .header-content h1 {
        font-size: 1.8rem;
    }

    .post-actions {
        justify-content: center;
    }
}

/* Loading & Error States */
.loading, .error {
    text-align: center;
    padding: 3rem;
    color: var(--text-secondary);
    font-style: italic;
}

.error {
    color: var(--accent-pink);
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: rgba(255,255,255,0.1);
}

::-webkit-scrollbar-thumb {
    background: var(--accent-blue);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--accent-purple);
}