/* ============================================================
   stellaris's BLOG — Modern Black & White Minimalist Line
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500&family=Noto+Serif+SC:wght@400;600&display=swap');

:root {
    /* Palette — pure black & white with neutral grays */
    --bg:           #ffffff;
    --bg-soft:      #fafafa;
    --fg:           #0a0a0a;
    --fg-2:         #404040;
    --fg-3:         #737373;
    --fg-4:         #a3a3a3;
    --line:         #e5e5e5;
    --line-2:       #d4d4d4;

    /* Typography */
    --font-sans:    'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", "PingFang SC", "Microsoft YaHei", sans-serif;
    --font-mono:    'JetBrains Mono', "SF Mono", Menlo, Consolas, monospace;
    --font-serif:   'Noto Serif SC', Georgia, serif;

    /* Layout */
    --maxw:         760px;
    --nav-h:        64px;

    /* Motion */
    --t:            220ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
    font-family: var(--font-sans);
    background: var(--bg);
    color: var(--fg);
    line-height: 1.7;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    font-feature-settings: "kern", "liga", "calt";
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button { font: inherit; cursor: pointer; }
::selection { background: var(--fg); color: var(--bg); }

/* ---------- Navigation ---------- */
nav {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255, 255, 255, 0.82);
    backdrop-filter: saturate(180%) blur(14px);
    -webkit-backdrop-filter: saturate(180%) blur(14px);
    border-bottom: 1px solid var(--line);
}
.nav-container {
    max-width: var(--maxw);
    margin: 0 auto;
    padding: 0 24px;
    height: var(--nav-h);
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.nav-brand {
    font-weight: 600;
    font-size: 0.92rem;
    letter-spacing: -0.01em;
    display: flex;
    align-items: center;
    gap: 8px;
}
.nav-brand::before {
    content: "";
    width: 10px;
    height: 10px;
    background: var(--fg);
    border-radius: 50%;
    display: inline-block;
}
.nav-brand a { color: var(--fg); }
.nav-links {
    display: flex;
    gap: 28px;
}
.nav-links a {
    color: var(--fg-3);
    font-size: 0.88rem;
    font-weight: 400;
    position: relative;
    padding: 4px 0;
    transition: color var(--t);
}
.nav-links a:hover,
.nav-links a.active { color: var(--fg); }
.nav-links a::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: 0;
    width: 0;
    height: 1px;
    background: var(--fg);
    transition: width var(--t);
}
.nav-links a:hover::after,
.nav-links a.active::after { width: 100%; }

/* ---------- Container ---------- */
.container {
    max-width: var(--maxw);
    margin: 0 auto;
    padding: 80px 24px 120px;
}

/* ---------- Typography ---------- */
h1 {
    font-size: clamp(1.9rem, 5vw, 2.6rem);
    font-weight: 600;
    letter-spacing: -0.035em;
    line-height: 1.15;
    margin-bottom: 1rem;
}
h2 {
    font-size: 1.15rem;
    font-weight: 600;
    letter-spacing: -0.005em;
    margin-top: 4.5rem;
    margin-bottom: 1.75rem;
    padding-bottom: 0.85rem;
    border-bottom: 1px solid var(--line);
    display: flex;
    align-items: center;
    gap: 14px;
}
h2 .sec-num {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    font-weight: 500;
    color: var(--fg-4);
    letter-spacing: 0.05em;
}
h3 {
    font-size: 1.02rem;
    font-weight: 600;
    letter-spacing: -0.005em;
    margin-bottom: 0.5rem;
}
p {
    color: var(--fg-2);
    margin-bottom: 1rem;
}
p:last-child { margin-bottom: 0; }
strong { color: var(--fg); font-weight: 600; }
em { font-style: italic; }

a.link {
    color: var(--fg);
    background-image: linear-gradient(var(--fg), var(--fg));
    background-position: 0 100%;
    background-repeat: no-repeat;
    background-size: 100% 1px;
    text-decoration: none;
    transition: background-size var(--t);
}
a.link:hover {
    background-size: 100% 2px;
}

/* ---------- Lists ---------- */
ul.list-line {
    list-style: none;
    border-top: 1px solid var(--line);
}
ul.list-line li {
    padding: 0.95rem 0;
    border-bottom: 1px solid var(--line);
    color: var(--fg-2);
    display: flex;
    align-items: baseline;
    gap: 16px;
    transition: padding-left var(--t);
}
ul.list-line li:hover { padding-left: 8px; }
ul.list-line li .li-label {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--fg-4);
    flex-shrink: 0;
    min-width: 90px;
}

/* ---------- Header (hero) ---------- */
.page-header {
    margin-bottom: 4rem;
    padding-bottom: 3rem;
    border-bottom: 1px solid var(--line);
}
.page-header .eyebrow {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--fg-4);
    text-transform: uppercase;
    letter-spacing: 0.15em;
    margin-bottom: 1.25rem;
    display: flex;
    align-items: center;
    gap: 10px;
}
.page-header .eyebrow::before {
    content: "";
    width: 24px;
    height: 1px;
    background: var(--fg-4);
    display: inline-block;
}
.page-header .subtitle {
    font-size: 1.05rem;
    color: var(--fg-3);
    font-weight: 400;
    margin-top: 0.5rem;
}

/* ---------- Cards ---------- */
.card {
    padding: 1.5rem 0;
    border-bottom: 1px solid var(--line);
    transition: padding-left var(--t);
    position: relative;
}
.card:first-of-type { border-top: 1px solid var(--line); }
.card:hover { padding-left: 1rem; }
.card::before {
    content: "";
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 0;
    height: 1px;
    background: var(--fg);
    transition: width var(--t);
}
.card:hover::before { width: 12px; }
.card h3 { margin-bottom: 0.4rem; }
.card h3 a { color: var(--fg); }
.card h3 a:hover { text-decoration: underline; text-underline-offset: 4px; }
.card .meta {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--fg-4);
    margin-bottom: 0.6rem;
    letter-spacing: 0.02em;
}
.card p {
    font-size: 0.95rem;
    margin-bottom: 0;
}

/* ---------- Footer ---------- */
footer {
    border-top: 1px solid var(--line);
    padding: 2.5rem 24px;
    text-align: center;
    color: var(--fg-4);
    font-size: 0.82rem;
    font-family: var(--font-mono);
    letter-spacing: 0.02em;
}
footer .foot-line {
    max-width: var(--maxw);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
}

/* ---------- Section label ---------- */
.section-label {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    color: var(--fg-4);
    text-transform: uppercase;
    letter-spacing: 0.15em;
    margin-bottom: 0.5rem;
}

/* ---------- Back link ---------- */
.back-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--fg-2);
    margin-top: 4rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--line);
    transition: gap var(--t), color var(--t);
}
.back-link:hover { gap: 14px; color: var(--fg); }
.back-link .arrow { transition: transform var(--t); }
.back-link:hover .arrow { transform: translateX(-4px); }

/* ---------- Markdown content (blog-post.html) ---------- */
#markdown-content {
    line-height: 1.85;
    font-size: 1.02rem;
}
#markdown-content h1 {
    font-size: 2rem;
    font-weight: 600;
    letter-spacing: -0.025em;
    margin-top: 0;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--line);
}
#markdown-content h2 {
    font-size: 1.25rem;
    margin-top: 2.5rem;
    margin-bottom: 1rem;
    padding-bottom: 0.6rem;
}
#markdown-content h2 .sec-num { display: none; }
#markdown-content h3 {
    font-size: 1.05rem;
    margin-top: 1.75rem;
    margin-bottom: 0.75rem;
}
#markdown-content p {
    margin-bottom: 1.25rem;
    color: var(--fg-2);
}
#markdown-content blockquote {
    border-left: 2px solid var(--fg);
    padding: 0.5rem 0 0.5rem 1.5rem;
    margin: 1.5rem 0;
    color: var(--fg-3);
    font-style: italic;
}
#markdown-content code {
    font-family: var(--font-mono);
    font-size: 0.88em;
    background: var(--bg-soft);
    padding: 2px 6px;
    border: 1px solid var(--line);
    border-radius: 3px;
}
#markdown-content pre {
    background: #0a0a0a;
    color: #fafafa;
    padding: 1.25rem 1.5rem;
    border-radius: 4px;
    overflow-x: auto;
    margin: 1.5rem 0;
    font-size: 0.88rem;
    line-height: 1.6;
}
#markdown-content pre code {
    background: none;
    border: none;
    padding: 0;
    color: inherit;
}
#markdown-content ul,
#markdown-content ol {
    margin: 1rem 0 1.25rem 1.5rem;
    color: var(--fg-2);
}
#markdown-content ul li,
#markdown-content ol li { margin-bottom: 0.4rem; }
#markdown-content a {
    color: var(--fg);
    background-image: linear-gradient(var(--fg), var(--fg));
    background-position: 0 100%;
    background-repeat: no-repeat;
    background-size: 100% 1px;
    transition: background-size var(--t);
}
#markdown-content a:hover { background-size: 100% 2px; }
#markdown-content hr {
    border: none;
    border-top: 1px solid var(--line);
    margin: 2.5rem 0;
}

/* ---------- Guestbook ---------- */
.gb-form {
    background: var(--bg);
    border: 1px solid var(--line);
    padding: 1.75rem;
    margin-bottom: 3rem;
    position: relative;
}
.gb-form::before {
    content: "";
    position: absolute;
    top: -1px;
    left: -1px;
    width: 16px;
    height: 16px;
    border-top: 1px solid var(--fg);
    border-left: 1px solid var(--fg);
}
.gb-form::after {
    content: "";
    position: absolute;
    bottom: -1px;
    right: -1px;
    width: 16px;
    height: 16px;
    border-bottom: 1px solid var(--fg);
    border-right: 1px solid var(--fg);
}
#reply-indicator {
    font-family: var(--font-mono);
    font-size: 0.82rem;
    color: var(--fg-2);
    margin-bottom: 1rem;
    padding: 0.6rem 0.9rem;
    background: var(--bg-soft);
    border-left: 2px solid var(--fg);
    display: none;
}
#reply-indicator button {
    background: none;
    border: 1px solid var(--line-2);
    padding: 2px 8px;
    margin-left: 8px;
    font-size: 0.78rem;
    color: var(--fg-2);
    transition: all var(--t);
}
#reply-indicator button:hover { background: var(--fg); color: var(--bg); border-color: var(--fg); }
.gb-form input,
.gb-form textarea {
    width: 100%;
    padding: 0.7rem 0.9rem;
    margin-bottom: 0.85rem;
    border: 1px solid var(--line);
    background: var(--bg);
    color: var(--fg);
    font-family: inherit;
    font-size: 0.95rem;
    border-radius: 0;
    transition: border-color var(--t);
}
.gb-form input:focus,
.gb-form textarea:focus {
    outline: none;
    border-color: var(--fg);
}
.gb-form textarea { resize: vertical; min-height: 100px; }
.gb-form button#submit-btn {
    background: var(--fg);
    color: var(--bg);
    border: 1px solid var(--fg);
    padding: 0.7rem 1.5rem;
    font-size: 0.9rem;
    font-weight: 500;
    letter-spacing: 0.02em;
    transition: all var(--t);
}
.gb-form button#submit-btn:hover:not(:disabled) {
    background: var(--bg);
    color: var(--fg);
}
.gb-form button#submit-btn:disabled {
    background: var(--fg-4);
    border-color: var(--fg-4);
    cursor: not-allowed;
}
#submit-status { margin-top: 0.75rem; font-size: 0.88rem; }

.comment-box {
    border: 1px solid var(--line);
    padding: 1.1rem 1.25rem;
    margin-bottom: 1rem;
    transition: border-color var(--t);
}
.comment-box:hover { border-color: var(--line-2); }
.reply-box {
    margin-left: 2.5rem;
    border-left: 2px solid var(--fg);
    padding-left: 1rem;
    margin-top: 0.75rem;
    margin-bottom: 1rem;
}
.comment-meta {
    font-size: 0.82rem;
    color: var(--fg-3);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 0.5rem;
}
.comment-meta strong { color: var(--fg); font-weight: 600; }
.comment-meta .meta-date {
    font-family: var(--font-mono);
    font-size: 0.76rem;
    color: var(--fg-4);
}
.comment-content {
    margin: 0.5rem 0 0.6rem;
    color: var(--fg-2);
    font-size: 0.95rem;
    line-height: 1.65;
}
.actions { display: flex; gap: 6px; }
.actions button {
    background: none;
    border: 1px solid var(--line-2);
    padding: 3px 10px;
    font-size: 0.78rem;
    color: var(--fg-2);
    font-family: var(--font-mono);
    transition: all var(--t);
}
.actions button:hover:not(:disabled) {
    background: var(--fg);
    color: var(--bg);
    border-color: var(--fg);
}
.actions button:disabled { opacity: 0.5; cursor: not-allowed; }

.status-msg {
    color: var(--fg-4);
    font-size: 0.9rem;
    font-family: var(--font-mono);
    padding: 1rem 0;
    text-align: center;
}
.error-msg {
    color: var(--fg);
    background: var(--bg-soft);
    padding: 0.9rem 1.1rem;
    border-left: 2px solid var(--fg);
    font-size: 0.88rem;
    margin-bottom: 1rem;
}

/* ---------- Empty state ---------- */
.empty-state {
    text-align: center;
    padding: 4rem 1rem;
    color: var(--fg-3);
}
.empty-state .es-num {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--fg-4);
    letter-spacing: 0.15em;
    margin-bottom: 1rem;
}
.empty-state h2 {
    border: none;
    justify-content: center;
    margin-top: 0;
    padding: 0;
}
.empty-state h2 .sec-num { display: none; }
.empty-state p { color: var(--fg-3); }

/* ---------- Entrance animation ---------- */
@keyframes fadeUp {
    from { opacity: 0; transform: translateY(8px); }
    to   { opacity: 1; transform: translateY(0); }
}
.fade-in { animation: fadeUp 0.5s cubic-bezier(0.4, 0, 0.2, 1) both; }
.fade-in.d1 { animation-delay: 0.05s; }
.fade-in.d2 { animation-delay: 0.12s; }
.fade-in.d3 { animation-delay: 0.20s; }
.fade-in.d4 { animation-delay: 0.28s; }

/* ---------- Responsive ---------- */
@media (max-width: 640px) {
    .container { padding: 56px 20px 80px; }
    .nav-container { padding: 0 20px; }
    .nav-links { gap: 18px; }
    .nav-links a { font-size: 0.82rem; }
    .nav-brand { font-size: 0.85rem; }
    h2 { margin-top: 3.5rem; }
    ul.list-line li { flex-direction: column; gap: 4px; }
    ul.list-line li .li-label { min-width: 0; }
    .reply-box { margin-left: 1.25rem; }
    footer .foot-line { flex-direction: column; gap: 6px; }
}

/* ---------- Print ---------- */
@media print {
    nav, footer { display: none; }
    .container { padding: 0; }
}