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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: #f0f2f5;
    color: #1c1e21;
    line-height: 1.34;
}

.navbar {
    background: #fff;
    border-bottom: 1px solid #dadde1;
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 16px;
    height: 56px;
}

.logo {
    font-size: 24px;
    font-weight: bold;
    color: #1877f2;
}

.nav-right {
    display: flex;
    align-items: center;
    gap: 12px;
}

.user-name {
    font-weight: 600;
    color: #1c1e21;
}

.btn-login, .btn-signup, .btn-logout {
    padding: 6px 16px;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 600;
    font-size: 14px;
    transition: all 0.2s;
}

.btn-login, .btn-logout {
    background: #e4e6ea;
    color: #1c1e21;
}

.btn-signup {
    background: #1877f2;
    color: #fff;
}

.btn-login:hover, .btn-logout:hover {
    background: #d8dadf;
}

.btn-signup:hover {
    background: #166fe5;
}

.main-feed {
    margin-top: 56px;
    padding: 20px 0;
    min-height: 100vh;
}

.feed-container {
    max-width: 680px;
    margin: 0 auto;
    padding: 0 16px;
}

.feed-item {
    background: #fff;
    border-radius: 8px;
    margin-bottom: 16px;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
    overflow: hidden;
}

.feed-header {
    display: flex;
    align-items: center;
    padding: 12px 16px;
    border-bottom: 1px solid #e4e6ea;
}

.feed-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: #1877f2;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    margin-right: 12px;
    font-size: 16px;
}

.feed-info h3 {
    font-size: 15px;
    font-weight: 600;
    color: #1c1e21;
    margin-bottom: 2px;
}

.feed-time {
    font-size: 13px;
    color: #65676b;
}

.feed-content {
    padding: 16px;
}

.feed-content p {
    font-size: 15px;
    color: #1c1e21;
    margin-bottom: 12px;
    line-height: 1.33;
}

.video-container {
    position: relative;
    border-radius: 8px;
    overflow: hidden;
    background: #000;
}

.feed-video {
    width: 100%;
    height: auto;
    max-height: 400px;
    display: block;
}

.image-container {
    border-radius: 8px;
    overflow: hidden;
}

.image-container img {
    width: 100%;
    height: auto;
    display: block;
}

.feed-actions {
    display: flex;
    align-items: center;
    padding: 8px 16px;
    border-top: 1px solid #e4e6ea;
    gap: 16px;
}

.action-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 8px 12px;
    border: none;
    background: transparent;
    color: #65676b;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    border-radius: 6px;
    transition: background 0.2s;
}

.action-btn:hover {
    background: #f2f3f4;
}

.like-btn.liked {
    color: #e41e3f;
}

.like-btn.liked i {
    color: #e41e3f;
}

.login-required-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
}

.video-preview-overlay {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: rgba(0, 0, 0, 0.8);
    color: #fff;
    padding: 12px 20px;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 600;
    display: none;
}

.subscription-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 2000;
}

.subscription-content {
    background: #fff;
    padding: 24px;
    border-radius: 8px;
    max-width: 400px;
    width: 90%;
    text-align: center;
}

.subscription-content h2 {
    margin-bottom: 16px;
    color: #1c1e21;
}

.subscription-plans {
    display: flex;
    gap: 12px;
    margin: 20px 0;
}

.plan {
    flex: 1;
    padding: 16px;
    border: 2px solid #e4e6ea;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
}

.plan:hover {
    border-color: #1877f2;
    background: #f0f8ff;
}

.plan h3 {
    font-size: 16px;
    margin-bottom: 8px;
    color: #1c1e21;
}

.plan p {
    font-size: 14px;
    color: #65676b;
}

@media (max-width: 768px) {
    .feed-container {
        max-width: 100%;
        padding: 0 8px;
    }
    
    .feed-item {
        margin-bottom: 8px;
        border-radius: 0;
    }
    
    .nav-container {
        padding: 0 12px;
    }
    
    .logo {
        font-size: 20px;
    }
    
    .subscription-plans {
        flex-direction: column;
    }
}