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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
    background-color: #fff;
    color: #000;
    line-height: 1.6;
}

.container {
    max-width: 600px;
    margin: 0 auto;
    padding: 0 16px;
}

/* Header */
.site-header {
    padding: 32px 0 24px;
    border-bottom: 1px solid #f0f0f0;
    margin-bottom: 24px;
}

.site-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.site-description {
    font-size: 0.95rem;
    color: #666;
}

/* Main Feed */
main {
    padding: 16px 0 32px;
}

/* Post Card */
.tweet-card {
    padding: 16px 0;
    border-bottom: 1px solid #f0f0f0;
    transition: background-color 0.2s;
}

.tweet-card:hover {
    background-color: #fafafa;
}

.tweet-main {
    width: 100%;
}

.tweet-header-meta {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 8px;
    font-size: 0.9rem;
    color: #666;
    flex-wrap: wrap;
}

.author-name {
    font-weight: 700;
    color: #000;
}

.dot {
    color: #ccc;
}

.tweet-time {
    color: #999;
}

/* Post Title */
.tweet-post-title {
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 8px;
    line-height: 1.4;
}

.tweet-post-title a {
    color: #000;
    text-decoration: none;
}

.tweet-post-title a:hover {
    text-decoration: underline;
}

/* Post Excerpt */
.tweet-excerpt {
    font-size: 0.95rem;
    color: #333;
    line-height: 1.5;
    margin-bottom: 8px;
}

/* Tags */
.post-tags {
    display: flex;
    gap: 6px;
    margin-top: 8px;
    flex-wrap: wrap;
}

.tag-btn {
    display: inline-block;
    background-color: #f0f0f0;
    color: #333;
    padding: 4px 10px;
    border: 1px solid transparent;
    border-radius: 16px;
    font-size: 0.8rem;
    cursor: pointer;
    transition: all 0.2s;
    font-family: inherit;
}

.tag-btn:hover {
    background-color: #e0e0e0;
}

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

/* Tag Filter Section */
.tag-filter-section {
    margin-bottom: 24px;
    padding: 16px;
    background-color: #fafafa;
    border-radius: 8px;
    border: 1px solid #f0f0f0;
}

.tag-filter-container {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin-bottom: 12px;
}

.tag-filter-btn {
    background-color: #fff;
    color: #333;
    padding: 6px 14px;
    border: 1px solid #ddd;
    border-radius: 20px;
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.2s;
    font-weight: 500;
    font-family: inherit;
}

.tag-filter-btn:hover {
    border-color: #999;
    background-color: #f9f9f9;
}

.tag-filter-btn.active {
    background-color: #000;
    color: #fff;
    border-color: #000;
}

.clear-filter-btn {
    background-color: #f5f5f5;
    color: #666;
    padding: 6px 12px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 0.85rem;
    cursor: pointer;
    transition: all 0.2s;
    font-family: inherit;
}

.clear-filter-btn:hover {
    background-color: #e0e0e0;
    color: #333;
}

/* Empty State */
.empty-feed {
    text-align: center;
    padding: 48px 16px;
    color: #999;
}

/* Post Detail View */
.post-detail {
    padding: 24px 0;
}

.post-header {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 16px;
    font-size: 0.9rem;
    color: #666;
    flex-wrap: wrap;
}

.post-author {
    font-weight: 700;
    color: #000;
}

.post-date {
    color: #999;
}

.post-title {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 16px;
    line-height: 1.3;
}

.post-tags-detail {
    display: flex;
    gap: 6px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}

.tag-link {
    display: inline-block;
    background-color: #f0f0f0;
    color: #333;
    padding: 6px 12px;
    border-radius: 16px;
    font-size: 0.85rem;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.2s;
}

.tag-link:hover {
    background-color: #e0e0e0;
}

.post-content {
    font-size: 1rem;
    line-height: 1.7;
    margin-bottom: 32px;
}

.post-content p {
    margin-bottom: 16px;
}

.post-content a {
    color: #0066cc;
    text-decoration: none;
}

.post-content a:hover {
    text-decoration: underline;
}

.post-footer {
    padding-top: 24px;
    border-top: 1px solid #f0f0f0;
}

.back-link {
    color: #000;
    text-decoration: none;
    font-weight: 600;
    font-size: 0.95rem;
}

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

/* Footer */
.site-footer {
    background-color: #f9f9f9;
    border-top: 1px solid #f0f0f0;
    padding: 32px 0;
    margin-top: auto;
}

.footer-content {
    max-width: 600px;
    margin: 0 auto;
    padding: 0 16px;
    text-align: center;
}

.footer-text {
    color: #666;
    font-size: 0.9rem;
    margin-bottom: 8px;
}

.footer-text a {
    color: #0066cc;
    text-decoration: none;
}

.footer-text a:hover {
    text-decoration: underline;
}

.footer-meta {
    color: #999;
    font-size: 0.85rem;
}

/* Mobile Responsiveness */
@media (max-width: 640px) {
    .container {
        padding: 0 12px;
    }

    .site-header {
        padding: 24px 0 16px;
        margin-bottom: 16px;
    }

    .site-title {
        font-size: 1.3rem;
    }

    .site-description {
        font-size: 0.9rem;
    }

    main {
        padding: 12px 0 24px;
    }

    .tweet-card {
        padding: 12px 0;
    }

    .tweet-post-title {
        font-size: 1rem;
    }

    .tweet-excerpt {
        font-size: 0.9rem;
    }

    .post-title {
        font-size: 1.5rem;
        margin-bottom: 12px;
    }

    .post-content {
        font-size: 0.95rem;
        margin-bottom: 24px;
    }

    .post-content p {
        margin-bottom: 12px;
    }

    .site-footer {
        padding: 24px 0;
    }

    .footer-text {
        font-size: 0.85rem;
    }

    .tag-filter-section {
        margin-bottom: 16px;
        padding: 12px;
        border-radius: 6px;
    }

    .tag-filter-container {
        gap: 6px;
        margin-bottom: 10px;
    }

    .tag-filter-btn {
        padding: 5px 12px;
        font-size: 0.85rem;
    }

    .clear-filter-btn {
        padding: 5px 10px;
        font-size: 0.8rem;
    }

    .tag-btn {
        padding: 3px 8px;
        font-size: 0.75rem;
    }
}