/* ============================================================
   Yincheng Zhou — personal site
   Plain HTML + CSS. No JS. No frameworks. ~6 KB.
   ============================================================ */

:root {
    --bg: #fefdfa;          /* almost-white, faint warm tint */
    --text: #1a1a1a;        /* off-black, easier on eyes than pure black */
    --muted: #707070;
    --accent: #8a3324;      /* burnt sienna — links only */
    --accent-soft: rgba(138, 51, 36, 0.35);
    --rule: #e6e1d6;        /* warm rule color */
    --max-w: 640px;
    --serif: 'Source Serif 4', 'Source Serif Pro', 'Charter', Georgia, serif;
    --mono: 'IBM Plex Mono', 'SF Mono', Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }

html {
    font-size: 18px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

body {
    margin: 0;
    font-family: var(--serif);
    font-size: 1rem;
    line-height: 1.72;
    color: var(--text);
    background: var(--bg);
    /* OpenType: kerning, ligatures, contextual alternates, old-style figures */
    font-feature-settings: "kern" 1, "liga" 1, "calt" 1, "onum" 1;
    /* Disable text selection across the site. */
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

main {
    max-width: var(--max-w);
    margin: 0 auto;
    padding: 5.5rem 1.5rem 4rem;
}

/* ---------- Header ---------- */

.site-header {
    margin-bottom: 3rem;
}

.site-header h1 {
    font-size: 1.75rem;
    font-weight: 600;
    margin: 0 0 0.4rem;
    letter-spacing: -0.012em;
    line-height: 1.2;
}

.site-header .subtitle {
    margin: 0;
    color: var(--muted);
    font-style: italic;
    font-size: 0.98rem;
}

/* ---------- Sections ---------- */

section {
    margin: 0 0 2.5rem;
}

h2 {
    font-family: var(--serif);
    font-size: 0.95rem;
    font-weight: 600;
    margin: 0 0 0.85rem;
    color: var(--muted);
    text-transform: lowercase;
    letter-spacing: 0.025em;
    /* Small flourish: hanging indent dot */
    position: relative;
}

p {
    margin: 0 0 1rem;
}

p:last-child {
    margin-bottom: 0;
}

p.meta {
    color: var(--muted);
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
}

p.meta em {
    font-style: italic;
}

/* ---------- Bio dropcap ---------- */

.bio p {
    /* Slightly larger lead paragraph */
    font-size: 1.02rem;
    line-height: 1.75;
}

.dropcap {
    float: left;
    font-family: var(--serif);
    font-size: 3.5rem;
    line-height: 0.88;
    font-weight: 500;
    margin: 0.32rem 0.6rem 0 0;
    color: var(--text);
    /* OpenType stylistic alternates if the font ships them */
    font-feature-settings: "ss01" 1, "kern" 1;
}

/* ---------- Links ---------- */

a {
    color: var(--accent);
    text-decoration: underline;
    text-decoration-thickness: 1px;
    text-underline-offset: 2.5px;
    text-decoration-color: var(--accent-soft);
    transition: text-decoration-color 0.15s ease;
}

a:hover {
    text-decoration-color: var(--accent);
}

a:focus-visible {
    outline: 2px solid var(--accent-soft);
    outline-offset: 3px;
    border-radius: 2px;
}

/* ---------- Typographic touches ---------- */

cite {
    font-style: italic;
}

abbr[title] {
    text-decoration: none;
    border-bottom: 1px dotted var(--muted);
    cursor: help;
}

em {
    font-style: italic;
}

.dot {
    color: var(--muted);
    padding: 0 0.4em;
}

/* ---------- Ornamental section divider ---------- */

hr.ornament {
    border: 0;
    text-align: center;
    margin: 3rem auto;
    height: 1rem;
    width: 100%;
    overflow: visible;
}

hr.ornament::after {
    content: "❦";  /* fleuron */
    display: inline-block;
    color: var(--rule);
    font-size: 1.15rem;
    line-height: 1;
    letter-spacing: 0;
}

/* ---------- Entry lists (writing, etc.) ---------- */

ul.entries {
    list-style: none;
    padding: 0;
    margin: 0;
}

ul.entries li {
    display: flex;
    align-items: baseline;
    gap: 1.25rem;
    margin: 0.5rem 0;
    padding: 0;
}

ul.entries .date {
    flex-shrink: 0;
    color: var(--muted);
    font-family: var(--mono);
    font-size: 0.82rem;
    letter-spacing: 0.01em;
    /* Monospace gives stable column alignment */
    font-variant-numeric: tabular-nums;
}

/* ---------- Plain ul (reading) ---------- */

ul.bare {
    list-style: none;
    padding: 0;
    margin: 0;
}

ul.bare li {
    margin: 0.45rem 0;
    padding-left: 1.1rem;
    position: relative;
}

ul.bare li::before {
    content: "·";
    color: var(--muted);
    position: absolute;
    left: 0.25rem;
    top: 0;
    font-weight: 600;
}

/* ---------- Footer / colophon ---------- */

.colophon {
    margin-top: 5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--rule);
    color: var(--muted);
    font-size: 0.82rem;
    font-style: italic;
    line-height: 1.5;
}

.colophon p {
    margin: 0;
}

/* ============================================================
   Article (essay) pages
   ============================================================ */

article.essay {
    /* Slightly wider for prose */
    max-width: 640px;
    margin: 0 auto;
}

article.essay header {
    margin: 0 0 2.5rem;
}

article.essay h1 {
    font-size: 1.55rem;
    font-weight: 600;
    line-height: 1.25;
    margin: 0 0 0.6rem;
    letter-spacing: -0.012em;
}

article.essay .essay-meta {
    color: var(--muted);
    font-size: 0.88rem;
    font-style: italic;
    margin: 0;
}

article.essay h2 {
    color: var(--text);
    text-transform: none;
    letter-spacing: 0;
    font-size: 1.1rem;
    margin: 2.25rem 0 0.75rem;
}

article.essay h3 {
    font-size: 1rem;
    font-weight: 600;
    margin: 1.5rem 0 0.5rem;
}

article.essay blockquote {
    margin: 1.25rem 0;
    padding: 0 0 0 1.25rem;
    border-left: 2px solid var(--rule);
    color: var(--text);
    font-style: italic;
}

article.essay code {
    font-family: var(--mono);
    font-size: 0.88em;
    background: rgba(138, 51, 36, 0.06);
    padding: 0.08em 0.32em;
    border-radius: 2px;
}

article.essay pre {
    font-family: var(--mono);
    font-size: 0.82rem;
    line-height: 1.55;
    background: #f7f4ec;
    border-left: 2px solid var(--rule);
    padding: 1rem 1.15rem;
    overflow-x: auto;
    margin: 1.25rem 0;
}

article.essay pre code {
    background: transparent;
    padding: 0;
    border-radius: 0;
    font-size: 1em;
}

article.essay hr {
    border: 0;
    text-align: center;
    margin: 2rem 0;
    height: 1rem;
}

article.essay hr::after {
    content: "* * *";
    color: var(--rule);
    letter-spacing: 0.5em;
}

article.essay .footnote-ref {
    font-size: 0.75em;
    vertical-align: super;
    line-height: 0;
}

.essay-nav {
    margin-top: 4rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--rule);
    font-size: 0.88rem;
    color: var(--muted);
}

.essay-nav a {
    color: var(--accent);
}

/* ============================================================
   Project demo pages
   ============================================================ */

.project-links {
    color: var(--muted);
    font-size: 0.9rem;
    margin: 0 0 2.5rem;
}

.demo-step {
    margin: 2.75rem 0;
}

.step-tag {
    font-family: var(--mono);
    font-size: 0.76rem;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    color: var(--muted);
    margin: 0 0 0.3rem;
}

.step-tag .step-no {
    color: var(--accent);
    margin-right: 0.55rem;
}

.demo-step h3 {
    font-size: 1.05rem;
    font-weight: 600;
    margin: 0 0 0.5rem;
    letter-spacing: -0.01em;
}

figure.shot {
    margin: 1.35rem 0 0;
    text-align: center;
}

figure.shot img {
    max-width: 100%;
    height: auto;
    border: 1px solid var(--rule);
    border-radius: 6px;
}

figure.shot-phone img {
    max-width: 290px;
    border-radius: 16px;
}

/* Alternating phone-and-text rows */
.demo-row {
    display: flex;
    align-items: center;
    gap: 2rem;
    margin: 2.75rem 0;
}

.demo-row.reverse { flex-direction: row-reverse; }

.demo-row .demo-copy { flex: 1; }

.demo-row .demo-copy > :last-child { margin-bottom: 0; }

/* Phone mockup */
.phone {
    flex: 0 0 auto;
    width: 218px;
    padding: 9px;
    background: #15120e;
    border-radius: 30px;
    box-shadow: 0 6px 24px rgba(21, 18, 14, 0.16);
    position: relative;
}

.phone .phone-notch {
    position: absolute;
    top: 9px;
    left: 50%;
    transform: translateX(-50%);
    width: 76px;
    height: 16px;
    background: #15120e;
    border-radius: 0 0 11px 11px;
    z-index: 2;
}

.phone .phone-screen {
    border-radius: 22px;
    overflow: hidden;
    background: #000;
    line-height: 0;
}

.phone .phone-screen img {
    display: block;
    width: 100%;
    height: auto;
}

@media (max-width: 540px) {
    figure.shot-phone img { max-width: 230px; }
    .demo-row,
    .demo-row.reverse {
        flex-direction: column;
        align-items: center;
        gap: 1.1rem;
    }
    .demo-row .phone { width: 230px; }
    .demo-row .demo-copy { width: 100%; }
}

/* ============================================================
   Print
   ============================================================ */

@media print {
    body {
        background: white;
        color: black;
        font-size: 11pt;
    }
    main { max-width: 100%; padding: 0; }
    a { color: black; text-decoration: underline; }
    hr.ornament::after { color: #999; }
    .colophon { display: none; }
}

/* ============================================================
   Mobile
   ============================================================ */

@media (max-width: 540px) {
    html { font-size: 17px; }
    main { padding: 3.5rem 1.25rem 3rem; }
    .site-header { margin-bottom: 2.25rem; }
    .site-header h1 { font-size: 1.55rem; }
    .bio p { font-size: 1rem; }
    .dropcap { font-size: 3rem; margin-right: 0.5rem; }
    hr.ornament { margin: 2.25rem auto; }
    ul.entries li {
        flex-direction: column;
        gap: 0.15rem;
        margin: 0.85rem 0;
    }
    ul.entries .date { font-size: 0.78rem; }
    .colophon { margin-top: 3.5rem; }
}

@media (max-width: 380px) {
    main { padding: 2.75rem 1.1rem 2.5rem; }
    .dropcap { font-size: 2.75rem; }
}