/* ==========================================================================
   Andy Chan — portfolio
   Warm editorial design: cream paper, charcoal ink, rust + olive accents.
   Plain CSS, no frameworks.
   ========================================================================== */

:root {
    --cream: #f5f1e9;
    --cream-deep: #ece6d8;
    --ink: #252b28;
    --ink-soft: #545a52;
    --rust: #a4422b;
    --rust-deep: #8c3722;
    --olive: #64684a;
    --line: rgba(37, 43, 40, 0.2);
    --line-faint: rgba(37, 43, 40, 0.1);
    --font-display: "IBM Plex Sans", "Helvetica Neue", sans-serif;
    --font-body: "DM Sans", "Helvetica Neue", Arial, sans-serif;
    --measure: 68ch;
    --gutter: clamp(1.25rem, 4vw, 4rem);
    --section-pad: clamp(4rem, 9vw, 7.5rem);
}

/* ------------------------------------------------------------------ base */

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    margin: 0;
    background-color: var(--cream);
    /* faint paper grain */
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='160' height='160' filter='url(%23n)' opacity='0.055'/%3E%3C/svg%3E");
    color: var(--ink);
    font-family: var(--font-body);
    font-size: 1.0625rem;
    line-height: 1.7;
    overflow-x: hidden;
}

img,
svg {
    max-width: 100%;
    height: auto;
    display: block;
}

h1,
h2,
h3 {
    font-family: var(--font-display);
    font-optical-sizing: auto;
    font-weight: 500;
    line-height: 1.05;
    letter-spacing: -0.01em;
    margin: 0;
    text-wrap: balance;
}

h1 {
    font-size: clamp(2.5rem, 7.2vw, 4.9rem);
    font-weight: 600;
    letter-spacing: -0.02em;
}

h2 {
    font-size: clamp(1.9rem, 4.2vw, 3.1rem);
}

h3 {
    font-size: clamp(1.3rem, 2.2vw, 1.65rem);
}

p {
    margin: 0 0 1.15em;
}

a {
    color: var(--rust);
    text-decoration-thickness: 1px;
    text-underline-offset: 0.18em;
}

a:hover {
    color: var(--rust-deep);
}

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

::selection {
    background: var(--rust);
    color: var(--cream);
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    margin: -1px;
    padding: 0;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
    border: 0;
}

.skip-link {
    position: absolute;
    top: -100%;
    left: var(--gutter);
    z-index: 20;
    padding: 0.75rem 1.25rem;
    background: var(--ink);
    color: var(--cream);
    text-decoration: none;
}

.skip-link:focus-visible {
    top: 0.75rem;
}

/* ------------------------------------------------------------- masthead */

.site-header {
    position: sticky;
    top: 0;
    z-index: 10;
    background: color-mix(in srgb, var(--cream) 92%, transparent);
    -webkit-backdrop-filter: blur(6px);
    backdrop-filter: blur(6px);
    border-bottom: 1px solid var(--line-faint);
}

.site-nav {
    display: flex;
    flex-wrap: wrap;
    align-items: baseline;
    justify-content: space-between;
    gap: 0 1.5rem;
    padding: 0.35rem var(--gutter);
    max-width: 1400px;
    margin: 0 auto;
}

.site-name {
    font-family: var(--font-display);
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--ink);
    text-decoration: none;
    /* keeps a 44px tap target without extra height */
    display: inline-flex;
    align-items: center;
    min-height: 44px;
}

.nav-links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.1rem;
    list-style: none;
    margin: 0;
    padding: 0;
}

.nav-links a {
    display: inline-flex;
    align-items: center;
    min-height: 44px;
    padding: 0 0.85rem;
    color: var(--ink);
    text-decoration: none;
    font-size: 0.95rem;
    letter-spacing: 0.02em;
    position: relative;
}

.nav-links a::after {
    content: "";
    position: absolute;
    left: 0.85rem;
    right: 0.85rem;
    bottom: 0.45rem;
    height: 1px;
    background: var(--rust);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.25s ease;
}

.nav-links a:hover::after,
.nav-links a:focus-visible::after {
    transform: scaleX(1);
}

/* ----------------------------------------------------------------- hero */

.hero {
    position: relative;
    padding: clamp(3rem, 8vw, 7rem) var(--gutter) 0;
    max-width: 1400px;
    margin: 0 auto;
    /* faint column grid over the hero only */
    background-image: repeating-linear-gradient(
        to right,
        var(--line-faint) 0,
        var(--line-faint) 1px,
        transparent 1px,
        transparent 25%
    );
}

.hero-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 0.65fr);
    gap: clamp(2rem, 6vw, 5rem);
    align-items: center;
}

.eyebrow {
    font-size: 0.78rem;
    font-weight: 700;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--rust);
    margin: 0 0 1.1rem;
}

.eyebrow-olive {
    color: var(--olive);
}

.section-no {
    color: var(--olive);
    margin-right: 0.9rem;
    font-weight: 500;
}

.lede {
    font-size: clamp(1.1rem, 1.9vw, 1.3rem);
    line-height: 1.65;
    color: var(--ink-soft);
    max-width: 44ch;
    margin: 1.4rem 0 0;
}

.hero-cta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.9rem;
    margin-top: 2.1rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 0.6rem 1.5rem;
    font-size: 0.98rem;
    font-weight: 500;
    letter-spacing: 0.015em;
    text-decoration: none;
    border: 1px solid var(--ink);
    border-radius: 2px;
    transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.btn-primary {
    background: var(--rust);
    border-color: var(--rust);
    color: var(--cream);
}

.btn-primary:hover {
    background: var(--rust-deep);
    border-color: var(--rust-deep);
    color: var(--cream);
}

.btn-ghost {
    background: transparent;
    color: var(--ink);
}

.btn-ghost:hover {
    background: var(--ink);
    border-color: var(--ink);
    color: var(--cream);
}

/* portrait: framed, offset rules */
.hero-portrait {
    margin: 0;
    justify-self: end;
    position: relative;
    width: min(288px, 100%);
}

.hero-portrait img {
    width: 100%;
    border: 1px solid var(--ink);
    filter: sepia(0.18) saturate(0.92);
    position: relative;
    z-index: 1;
}

.hero-portrait::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    /* image is square, so pad to a square matching just the photo */
    padding-bottom: 100%;
    transform: translate(10px, 10px);
    border: 1px solid var(--rust);
}

.hero-portrait figcaption {
    margin-top: 1.15rem;
    padding-top: 0.6rem;
    border-top: 1px solid var(--line);
    font-size: 0.82rem;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--ink-soft);
}

/* program context strip */
.program-strip {
    display: flex;
    flex-wrap: wrap;
    align-items: baseline;
    gap: 0.5rem 2rem;
    margin-top: clamp(3rem, 6vw, 5rem);
    padding: 1.15rem 0 1.35rem;
    border-top: 1px solid var(--line);
    border-bottom: 1px solid var(--line);
}

.program-label {
    margin: 0;
    font-size: 0.78rem;
    font-weight: 700;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--ink-soft);
}

.program-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem 0;
    list-style: none;
    margin: 0;
    padding: 0;
}

.program-list li {
    font-family: var(--font-display);
    font-size: 1.15rem;
    font-weight: 500;
    color: var(--ink);
}

.program-list li + li::before {
    content: "·";
    margin: 0 0.9rem;
    color: var(--rust);
    font-style: normal;
}

/* -------------------------------------------------------------- sections */

.section {
    padding: var(--section-pad) var(--gutter);
    max-width: 1400px;
    margin: 0 auto;
}

[id] {
    scroll-margin-top: 4.5rem;
}

.anchor-alias {
    display: block;
    height: 0;
}

.section-head {
    max-width: var(--measure);
    margin-bottom: clamp(2.5rem, 6vw, 4.5rem);
}

.section-head h2 {
    margin-bottom: 1rem;
}

.section-intro {
    color: var(--ink-soft);
    font-size: 1.05rem;
    max-width: 56ch;
}

/* ----------------------------------------------------------------- cases */

.case {
    border-top: 1px solid var(--line);
    padding: clamp(1.8rem, 4vw, 2.8rem) 0;
}

.case-meta {
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    color: var(--olive);
    margin-bottom: 0.85rem;
}

/* keep the meta link a >=44px tap target without growing the line box */
.case-meta a {
    display: inline-flex;
    align-items: center;
    min-height: 44px;
    margin-block: -0.7rem;
    vertical-align: middle;
}

.case h3 {
    margin-bottom: 1.15rem;
}

.case p {
    max-width: var(--measure);
}

.fact-label {
    color: var(--ink);
    font-weight: 700;
    padding-right: 0.15em;
}

/* featured split row */
.case-feature {
    display: grid;
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    gap: clamp(2rem, 6vw, 4.5rem);
    align-items: start;
    border-top: 1px solid var(--ink);
}

/* workflow illustration card */
.workflow-fig {
    margin: 0;
    padding: clamp(1.2rem, 3vw, 2rem);
    background: var(--cream-deep);
    border: 1px solid var(--line);
}

.workflow-fig svg {
    width: 100%;
}

.wf-line {
    stroke: var(--ink-soft);
    stroke-width: 1;
    stroke-dasharray: 3 5;
}

.wf-node circle {
    fill: var(--cream);
    stroke: var(--ink);
    stroke-width: 1.25;
}

.wf-ring {
    fill: none !important;
    stroke: var(--rust) !important;
    stroke-dasharray: 4 4;
}

.wf-dot {
    fill: var(--rust) !important;
    stroke: none !important;
}

.wf-glyph {
    fill: none;
    stroke: var(--rust);
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.wf-node text {
    font-family: var(--font-body);
    font-size: 0.82rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    fill: var(--ink);
    text-anchor: middle;
}

.workflow-fig figcaption {
    margin-top: 0.4rem;
    font-size: 0.82rem;
    letter-spacing: 0.05em;
    color: var(--ink-soft);
}

/* three supporting cases: context left, story right */
.case-list {
    display: block;
}

.case-row {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 2fr);
    gap: clamp(2rem, 5vw, 4rem);
    align-items: start;
}

.case-heading h3 {
    font-size: clamp(1.5rem, 2.5vw, 2rem);
}

.source-link {
    margin: 0;
    font-size: 0.95rem;
}

/* >=44px tap target without loosening surrounding spacing */
.source-link a {
    display: inline-flex;
    align-items: center;
    min-height: 44px;
    margin-block: -0.65rem;
    font-weight: 500;
}

.case-body {
    max-width: var(--measure);
    border-left: 1px solid var(--line);
    padding-left: clamp(1.5rem, 3vw, 2.5rem);
}

/* tags */
.tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.45rem;
    list-style: none;
    margin: 1.4rem 0 0;
    padding: 0;
}

.tags li {
    font-size: 0.75rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--ink-soft);
    border: 1px solid var(--line);
    border-radius: 999px;
    padding: 0.28rem 0.75rem;
}

/* details / summary */
.case-more {
    margin-top: 1.35rem;
    max-width: var(--measure);
}

.case-more summary {
    display: inline-flex;
    align-items: center;
    min-height: 44px;
    cursor: pointer;
    font-size: 0.88rem;
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--rust);
    list-style: none;
}

.case-more summary::-webkit-details-marker {
    display: none;
}

.case-more summary::after {
    content: "+";
    margin-left: 0.6rem;
    font-family: var(--font-display);
    font-size: 1.15rem;
    line-height: 1;
    transition: transform 0.2s ease;
}

.case-more[open] summary::after {
    transform: rotate(45deg);
}

.case-more summary:hover {
    color: var(--rust-deep);
}

.case-more p {
    margin-top: 0.4rem;
    color: var(--ink-soft);
    font-size: 0.98rem;
}

/* learning tile */
.learning {
    margin-top: clamp(2.5rem, 6vw, 4rem);
    padding: clamp(1.6rem, 3.5vw, 2.4rem);
    border: 1px solid var(--line);
    border-left: 3px solid var(--olive);
    background: var(--cream-deep);
    display: grid;
    grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.4fr);
    gap: 0.5rem clamp(1.5rem, 4vw, 3rem);
    align-items: start;
}

.learning p {
    margin: 0;
    color: var(--ink-soft);
}

.learning .tags {
    grid-column: 2;
    margin-top: 0;
}

/* ----------------------------------------------------------------- about */

.about {
    border-top: 1px solid var(--ink);
}

.about-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
    gap: clamp(2.5rem, 7vw, 6rem);
    align-items: start;
}

.about-bio p:first-child {
    font-size: 1.2rem;
    line-height: 1.65;
}

.edu-note {
    margin-top: 1.8rem;
    padding-top: 1.1rem;
    border-top: 1px solid var(--line);
    font-size: 0.95rem;
    color: var(--ink-soft);
}

.about-side {
    display: grid;
    gap: 2.5rem;
}

.about-side h3 {
    font-size: 1.15rem;
    margin-bottom: 1rem;
}

.skill-groups {
    margin: 0;
}

.skill-group {
    padding: 0.85rem 0;
    border-top: 1px solid var(--line);
}

.skill-group:last-child {
    border-bottom: 1px solid var(--line);
}

.skill-group dt {
    font-size: 0.78rem;
    font-weight: 700;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--rust);
    margin-bottom: 0.3rem;
}

.skill-group dd {
    margin: 0;
    color: var(--ink);
    font-size: 0.98rem;
}

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

.earlier-list li {
    display: flex;
    flex-wrap: wrap;
    align-items: baseline;
    justify-content: space-between;
    gap: 0 1rem;
    border-top: 1px solid var(--line-faint);
}

/* padding on the anchor keeps each link a >=44px tap target */
.earlier-list li a,
.earlier-list li span {
    padding: 0.65rem 0;
}

.earlier-list li span {
    font-size: 0.85rem;
    color: var(--ink-soft);
}

.earlier-note {
    margin: 0.9rem 0 0;
    font-size: 0.85rem;
    color: var(--ink-soft);
    font-style: italic;
}

/* --------------------------------------------------------------- contact */

.contact {
    border-top: 1px solid var(--ink);
}

.contact h2 {
    max-width: 14ch;
}

.contact-lede {
    margin-top: 1.3rem;
    max-width: 46ch;
    color: var(--ink-soft);
    font-size: 1.1rem;
}

.contact-links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.9rem;
    margin-top: 2rem;
}

/* ---------------------------------------------------------------- footer */

.site-footer {
    border-top: 1px solid var(--line);
    padding: 1.5rem var(--gutter) 2rem;
    max-width: 1400px;
    margin: 0 auto;
}

.site-footer p {
    margin: 0;
    font-size: 0.85rem;
    color: var(--ink-soft);
}

/* ---------------------------------------------------------------- motion */

/* entry stagger: pure CSS, honored only when motion is allowed */
@media (prefers-reduced-motion: no-preference) {
    .rise {
        animation: rise 0.75s cubic-bezier(0.2, 0.6, 0.2, 1) both;
    }

    .hero-copy .rise:nth-child(2) { animation-delay: 0.08s; }
    .hero-copy .rise:nth-child(3) { animation-delay: 0.16s; }
    .hero-copy .rise:nth-child(4) { animation-delay: 0.24s; }
    .hero-portrait.rise { animation-delay: 0.3s; }

    @keyframes rise {
        from {
            opacity: 0;
            transform: translateY(18px);
        }
        to {
            opacity: 1;
            transform: none;
        }
    }
}

/* scroll reveals: only hidden when JS is running; content never depends on JS */
html.js [data-reveal] {
    opacity: 0;
    transform: translateY(14px);
}

html.js [data-reveal].is-visible {
    opacity: 1;
    transform: none;
    transition: opacity 0.7s ease, transform 0.7s cubic-bezier(0.2, 0.6, 0.2, 1);
}

/* never keep content invisible while keyboard focus is inside it */
html.js [data-reveal]:focus-within {
    opacity: 1;
    transform: none;
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    *,
    *::before,
    *::after {
        animation: none !important;
        transition: none !important;
    }

    html.js [data-reveal],
    html.js [data-reveal].is-visible {
        opacity: 1;
        transform: none;
    }
}

/* ------------------------------------------------------------ responsive */

@media (max-width: 48em) {
    .case-row {
        grid-template-columns: minmax(0, 1fr);
        gap: 1.25rem;
    }

    .case-body {
        border-left: 0;
        padding-left: 0;
        max-width: none;
    }
}

@media (max-width: 64em) {
    .hero-grid,
    .case-feature,
    .about-grid,
    .learning {
        grid-template-columns: minmax(0, 1fr);
    }

    .hero-portrait {
        justify-self: start;
        width: min(220px, 70%);
    }

    .learning .tags {
        grid-column: auto;
    }
}

@media (max-width: 40em) {
    body {
        font-size: 1rem;
    }

    .site-nav {
        padding: 0.25rem var(--gutter);
    }

    .nav-links a {
        padding: 0 0.55rem;
    }

    .hero {
        padding-top: 2.5rem;
    }

    .program-strip {
        gap: 0.4rem 1.2rem;
    }
}