/* reset & base */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bg: #fafaf9;
    --text: #1c1917;
    --text-secondary: #78716c;
    --accent: #a8a29e;
    --border: #e7e5e4;
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 3rem;
    --spacing-xl: 4rem;
    --max-width: 640px;
    --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font);
    font-size: 16px;
    line-height: 1.75;
    color: var(--text);
    background: var(--bg);
    font-weight: 400;
    text-transform: lowercase;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* layout */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: var(--spacing-md);
}

/* header */
header {
    padding: var(--spacing-xl) 0;
    border-bottom: 1px solid var(--border);
    margin-bottom: var(--spacing-lg);
}

.site-title {
    font-size: 1.25rem;
    font-weight: 500;
    color: var(--text);
    text-decoration: none;
    letter-spacing: -0.02em;
}

.site-title:hover {
    color: var(--text-secondary);
}

.site-desc {
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-top: var(--spacing-xs);
    letter-spacing: 0.02em;
}

/* posts */
.posts {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.post {
    padding-bottom: var(--spacing-sm);
    border-bottom: 1px solid var(--border);
    transition: background 0.2s ease;
}

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

.post-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    user-select: none;
    padding: var(--spacing-xs) 0;
}

.post-header:hover .post-title {
    color: var(--text-secondary);
}

/* post meta */
.post-meta {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xs);
    pointer-events: none;
}

.post-meta time {
    font-size: 0.8125rem;
    color: var(--accent);
}

.post-tag {
    font-size: 0.75rem;
    color: var(--text-secondary);
    background: var(--border);
    padding: 0.1rem 0.4rem;
    border-radius: 3px;
}

/* post title */
.post-title {
    font-size: 1.125rem;
    font-weight: 500;
    margin: 0;
    letter-spacing: -0.01em;
    line-height: 1.3;
    transition: color 0.2s ease;
}

.post-toggle {
    font-size: 1.25rem;
    line-height: 1;
    color: var(--accent);
    transition: transform 0.3s ease;
    margin-left: var(--spacing-sm);
}

.post.is-expanded .post-toggle {
    transform: rotate(45deg);
}

/* post content */
.post-content-wrapper {
    display: grid;
    grid-template-rows: 0fr;
    transition: grid-template-rows 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    overflow: hidden;
}

.post.is-expanded .post-content-wrapper {
    grid-template-rows: 1fr;
}

.post-content {
    min-height: 0;
    color: var(--text);
    padding-top: var(--spacing-sm);
    padding-bottom: var(--spacing-md);
}

.post-content p {
    margin-bottom: var(--spacing-sm);
}

.post-content p:last-child {
    margin-bottom: 0;
}

.post-content strong {
    font-weight: 500;
}

.post-content a {
    color: var(--text);
    text-decoration: underline;
    text-underline-offset: 2px;
}

.post-content a:hover {
    color: var(--text-secondary);
}

/* footer */
footer {
    padding: var(--spacing-xl) 0 var(--spacing-lg);
    margin-top: var(--spacing-lg);
    border-top: 1px solid var(--border);
}

.footer-links {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
}

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.875rem;
    transition: color 0.2s ease;
}

.footer-links a:hover {
    color: var(--text);
}

.copyright {
    font-size: 0.8125rem;
    color: var(--accent);
}

/* comments */
.comments-section {
    margin-top: var(--spacing-md);
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--border);
}

.comments-title {
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
}

.comment {
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid var(--border);
}

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

.comment-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 0.25rem;
}

.comment-author {
    font-weight: 500;
    font-size: 0.875rem;
}

.comment-date {
    font-size: 0.75rem;
    color: var(--accent);
}

.comment-text {
    font-size: 0.875rem;
    color: var(--text);
    line-height: 1.6;
}

.no-comments {
    font-size: 0.875rem;
    color: var(--accent);
    font-style: italic;
}

/* comment form */
.comment-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    margin-top: var(--spacing-sm);
}

.comment-form input,
.comment-form textarea {
    font-family: var(--font);
    font-size: 0.875rem;
    padding: var(--spacing-xs);
    border: 1px solid var(--border);
    border-radius: 4px;
    background: var(--bg);
    color: var(--text);
    transition: border-color 0.2s ease;
}

.comment-form input:focus,
.comment-form textarea:focus {
    outline: none;
    border-color: var(--accent);
}

.comment-form textarea {
    resize: vertical;
    min-height: 80px;
}

.captcha-row {
    display: flex;
    gap: var(--spacing-sm);
    align-items: flex-end;
}

.captcha-label {
    flex: 1;
    font-size: 0.8125rem;
    color: var(--text-secondary);
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.captcha-label input {
    max-width: 100px;
}

.submit-btn {
    font-family: var(--font);
    font-size: 0.875rem;
    padding: var(--spacing-xs) var(--spacing-md);
    background: var(--text);
    color: var(--bg);
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: background 0.2s ease;
    white-space: nowrap;
}

.submit-btn:hover {
    background: var(--text-secondary);
}

.form-note {
    font-size: 0.75rem;
    color: var(--accent);
    margin-top: 0.25rem;
}

/* comment success */
.comment-success {
    padding: var(--spacing-md);
    background: var(--border);
    border-radius: 4px;
    text-align: center;
}

.comment-success p {
    font-size: 0.875rem;
    margin-bottom: var(--spacing-xs);
    color: var(--text);
}

.comment-success p:last-child {
    margin-bottom: 0;
}

.comment-json-box {
    background: var(--bg);
    border: 1px solid var(--accent);
    border-radius: 4px;
    padding: var(--spacing-sm);
    margin: var(--spacing-sm) 0;
    max-height: 200px;
    overflow-y: auto;
    text-align: left;
}

.comment-json-box pre {
    font-family: 'Courier New', monospace;
    font-size: 0.75rem;
    margin: 0;
    color: var(--text);
    white-space: pre-wrap;
    word-break: break-word;
}

.copy-btn,
.email-btn,
.github-submit-btn {
    display: inline-block;
    margin: 0.25rem;
    padding: var(--spacing-xs) var(--spacing-md);
    background: var(--text);
    color: #ffffff !important;
    text-decoration: none;
    border: none;
    border-radius: 4px;
    font-size: 0.875rem;
    font-family: var(--font);
    cursor: pointer;
    transition: background 0.2s ease;
}

.copy-btn:hover,
.email-btn:hover,
.github-submit-btn:hover {
    background: var(--text-secondary);
    color: #ffffff !important;
}

/* responsive */
@media (max-width: 480px) {
    :root {
        --spacing-lg: 2rem;
        --spacing-xl: 3rem;
    }

    .post-title {
        font-size: 1.25rem;
    }

    .captcha-row {
        flex-direction: column;
        align-items: stretch;
    }

    .captcha-label input {
        max-width: 100%;
    }

    .submit-btn {
        width: 100%;
    }
}