/* ==========================================================================
   Lucky Sah — portfolio styles
   One stylesheet for the whole site. Colours and sizes live in :root.
   ========================================================================== */

:root {
  --bg: #ffffff;
  --bg-soft: #f6f7f9;
  --text: #16181d;
  --muted: #5b6270;
  --border: #e3e6eb;
  --accent: #1f4fd1;
  --accent-dark: #173c9f;

  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --width: 960px;
  --width-article: 720px;
  --radius: 8px;
}

/* ---------- Base ---------- */

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

@media (prefers-reduced-motion: no-preference) {
  html {
    scroll-behavior: smooth;
  }
}

html {
  scroll-padding-top: 80px; /* keeps headings clear of the sticky header */
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

h1,
h2,
h3 {
  line-height: 1.25;
  letter-spacing: -0.01em;
}

h1 {
  font-size: clamp(2.2rem, 5vw, 3rem);
  margin: 0 0 12px;
}

h2 {
  font-size: 1.6rem;
  margin: 0 0 24px;
}

h3 {
  font-size: 1.15rem;
  margin: 0 0 6px;
}

p {
  margin: 0 0 16px;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

a:focus-visible,
.button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

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

.container {
  max-width: var(--width);
  margin: 0 auto;
  padding: 0 24px;
}

.muted {
  color: var(--muted);
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.95);
  border-bottom: 1px solid var(--border);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 64px;
}

.logo {
  font-weight: 700;
  color: var(--text);
}

.logo:hover {
  text-decoration: none;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 24px;
}

.site-nav a {
  color: var(--muted);
  font-size: 15px;
}

.site-nav a:hover {
  color: var(--text);
  text-decoration: none;
}

/* ---------- Buttons ---------- */

.button {
  display: inline-block;
  padding: 10px 18px;
  border: 1px solid var(--accent);
  border-radius: var(--radius);
  background: var(--accent);
  color: #fff;
  font-size: 15px;
  font-weight: 600;
}

.button:hover {
  background: var(--accent-dark);
  border-color: var(--accent-dark);
  text-decoration: none;
}

.button-outline {
  background: transparent;
  color: var(--accent);
}

.button-outline:hover {
  background: var(--bg-soft);
  color: var(--accent-dark);
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

/* ---------- Home: two-column layout ---------- */

.layout {
  max-width: 1160px;
  margin: 0 auto;
  padding: 64px 32px;
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 72px;
}

/* Left column. Stays in view while scrolling, but only on screens tall
   enough to show all of it. */
.sidebar {
  align-self: start;
}

@media (min-height: 960px) {
  .sidebar {
    position: sticky;
    top: 64px;
  }
}

.photo {
  position: relative;
  width: 100%;
  max-width: 240px;
  aspect-ratio: 4 / 5;
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 24px;
}

.photo span {
  font-size: 48px;
  font-weight: 700;
  color: var(--border);
}

.photo img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.name {
  font-size: 1.75rem;
  margin: 0 0 4px;
}

.role {
  color: var(--muted);
  margin-bottom: 24px;
}

.side-info {
  margin: 0;
  padding: 24px 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  font-size: 15px;
}

.side-info dt {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  margin-top: 16px;
}

.side-info dt:first-child {
  margin-top: 0;
}

.side-info dd {
  margin: 2px 0 0;
  line-height: 1.5;
}

.side-links {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 16px;
}

.side-nav {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding-top: 24px;
}

.side-nav a {
  color: var(--muted);
  font-size: 15px;
}

.side-nav a:hover {
  color: var(--text);
  text-decoration: none;
}

/* Right column */
.content {
  min-width: 0;
}

.section {
  padding: 48px 0;
  border-top: 1px solid var(--border);
}

.section:first-child {
  padding-top: 0;
  border-top: none;
}

.content p {
  max-width: 680px;
}

.content-footer {
  border-top: 1px solid var(--border);
  padding-top: 24px;
  font-size: 14px;
  color: var(--muted);
}

/* Two-column "label | content" rows used for experience and education */
.entry {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0 24px;
  margin-bottom: 32px;
}

.entry.education {
  margin-top: 32px;
}

.entry:last-child {
  margin-bottom: 0;
}

.entry .org {
  color: var(--muted);
  margin-bottom: 8px;
}

.entry .date {
  color: var(--muted);
  font-size: 15px;
  white-space: nowrap;
}

.entry ul {
  grid-column: 1 / -1;
  margin: 0;
  padding-left: 20px;
  color: var(--muted);
}

.entry li {
  margin-bottom: 4px;
}

/* "What I work on": one clickable card per area (one per page in the work folder) */
.area-cards {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.area-card {
  display: flex;
  flex-direction: column;
  padding: 22px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  transition: border-color 0.15s ease, background 0.15s ease;
}

.area-card:hover {
  border-color: var(--accent);
  background: var(--bg-soft);
  text-decoration: none;
}

.area-card h3 {
  font-size: 1.05rem;
  margin: 0 0 6px;
}

.area-card p {
  margin: 0 0 14px;
  font-size: 15px;
  color: var(--muted);
  flex: 1;
}

.area-card .chips {
  margin-bottom: 14px;
}

/* Small rounded labels for tools and skills */
.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.chips li {
  padding: 3px 10px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--bg);
  font-size: 13px;
  color: var(--text);
}

/* Links under an experience entry to the related area pages */
.entry-tags {
  grid-column: 1 / -1;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 10px;
}

.entry-tags a {
  padding: 2px 10px;
  border-radius: 999px;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  font-size: 13px;
  color: var(--muted);
}

.entry-tags a:hover {
  border-color: var(--accent);
  color: var(--accent);
  text-decoration: none;
}

/* Area of work pages */
.area-page {
  padding: 40px 0 80px;
}

.area-page .lead {
  font-size: 1.15rem;
  color: var(--muted);
  max-width: 680px;
}

.area-section {
  padding: 40px 0;
  border-top: 1px solid var(--border);
  margin-top: 32px;
}

.area-section + .area-section {
  margin-top: 0;
}

.area-section h2 {
  font-size: 1.3rem;
  margin: 0 0 20px;
}

.area-section .section-head h2 {
  margin: 0;
}

.area-section .chips li {
  font-size: 14px;
  padding: 5px 12px;
}

.area-text h2 {
  margin-top: 0;
}

.muted {
  color: var(--muted);
}

.area-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 28px;
  font-weight: 600;
}

/* Awards & activities: two short lists side by side */
.columns-2 {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px 40px;
  margin-bottom: 40px;
}

.columns-2 h3 {
  font-size: 1rem;
  margin: 0 0 10px;
}

.plain-list {
  margin: 0;
  padding-left: 20px;
  color: var(--muted);
}

.plain-list li {
  margin-bottom: 4px;
}

/* Section heading with a link on the right ("View all projects →") */
.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px 24px;
  margin-bottom: 24px;
}

.section-head h2 {
  margin: 0;
}

.section-head a {
  font-size: 15px;
  font-weight: 600;
}

/* All projects page */
.projects-page {
  padding: 56px 0 80px;
}

.projects-page .lead {
  color: var(--muted);
  font-size: 1.15rem;
  margin-bottom: 40px;
}

/* Project cards */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  align-items: start; /* a card without a photo doesn't stretch to match one with */
  gap: 20px;
}

.card {
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  color: var(--text);
  transition: border-color 0.15s ease;
}

.card:hover {
  border-color: var(--accent);
  text-decoration: none;
}

.card img {
  aspect-ratio: 16 / 10;
  object-fit: cover;
  background: var(--bg-soft);
  border-bottom: 1px solid var(--border);
}

.card-body {
  padding: 20px;
  display: flex;
  flex-direction: column;
  flex: 1;
}

.card-body p {
  color: var(--muted);
  font-size: 15px;
  flex: 1;
}

.card-link {
  color: var(--accent);
  font-size: 15px;
  font-weight: 600;
}

.tag {
  display: block;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 8px;
}

/* Publications */
.publication {
  margin: 0;
  color: var(--muted);
}

.publication strong {
  color: var(--text);
}

/* Skills */
.skills {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 12px 24px;
  margin: 0;
}

.skills dt {
  font-weight: 600;
}

.skills dd {
  margin: 0;
  color: var(--muted);
}

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

.site-footer {
  border-top: 1px solid var(--border);
  padding: 28px 0;
  font-size: 14px;
  color: var(--muted);
}

.site-footer .container {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px 24px;
}

.site-footer nav {
  display: flex;
  gap: 20px;
}

.site-footer a {
  color: var(--muted);
}

/* ---------- Project / tutorial pages ---------- */

.article {
  max-width: var(--width-article);
  margin: 0 auto;
  padding: 40px 24px 80px;
}

.back {
  display: inline-block;
  font-size: 15px;
  margin-bottom: 32px;
}

.article .lead {
  font-size: 1.15rem;
  color: var(--muted);
}

.meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 32px;
  margin: 24px 0 0;
  padding: 16px 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  font-size: 15px;
}

.meta div {
  display: flex;
  flex-direction: column;
}

.meta dt {
  color: var(--muted);
  font-size: 13px;
}

.meta dd {
  margin: 0;
}

.article h2 {
  font-size: 1.4rem;
  margin: 48px 0 16px;
}

.article h3 {
  margin: 32px 0 12px;
}

.article ul,
.article ol {
  padding-left: 22px;
}

.article li {
  margin-bottom: 6px;
}

.article figure {
  margin: 32px 0;
}

.article figcaption {
  margin-top: 8px;
  font-size: 14px;
  color: var(--muted);
}

.article figure img {
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.article table {
  width: 100%;
  border-collapse: collapse;
  font-size: 15px;
  margin: 16px 0;
}

.article th,
.article td {
  text-align: left;
  padding: 8px 12px;
  border-bottom: 1px solid var(--border);
}

.article th {
  background: var(--bg-soft);
}

code {
  font-family: var(--mono);
  font-size: 0.9em;
  background: var(--bg-soft);
  padding: 2px 5px;
  border-radius: 4px;
}

pre {
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  overflow-x: auto;
  font-size: 14px;
  line-height: 1.5;
}

pre code {
  background: none;
  padding: 0;
}

/* Content written in Markdown (each project index.md) */
.article .cover {
  margin-top: 32px;
}

.article img,
.article video,
.article iframe {
  width: 100%;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  margin: 24px 0 8px;
}

.article iframe {
  aspect-ratio: 16 / 9;
  height: auto;
}

/* Shown where a project's demo video will go, until the file is added */
.media-placeholder {
  aspect-ratio: 16 / 9;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 32px 0 8px;
  border: 1px dashed var(--border);
  border-radius: var(--radius);
  background: var(--bg-soft);
  color: var(--muted);
  font-size: 15px;
}

/* Photos in the text: tall (portrait) ones are capped so they don't fill the screen */
.article img:not(.cover) {
  width: auto;
  max-width: 100%;
  max-height: 560px;
  margin-left: auto;
  margin-right: auto;
}

/* Diagrams (SVG) always fill the column so their text stays readable */
.article img[src$=".svg"] {
  width: 100%;
  max-height: none;
  background: #fff;
}

/* *Caption* written on the line right after an image */
.article img + em {
  display: block;
  font-size: 14px;
  color: var(--muted);
  text-align: center;
  margin-bottom: 24px;
}

.article blockquote {
  margin: 24px 0;
  padding: 14px 18px;
  background: var(--bg-soft);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
  color: var(--muted);
}

.article blockquote p:last-child {
  margin-bottom: 0;
}

.article .highlight {
  background: none;
}

/* Wide tables scroll sideways on phones instead of squashing */
.article table {
  display: block;
  overflow-x: auto;
}

/* Collapsible sections: <details markdown="1"><summary>Title</summary> ... </details> */
.article details {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0 18px;
  margin: 20px 0;
}

.article summary {
  cursor: pointer;
  font-weight: 600;
  padding: 14px 0;
}

.article details[open] summary {
  border-bottom: 1px solid var(--border);
  margin-bottom: 8px;
}

.note {
  background: var(--bg-soft);
  border-left: 3px solid var(--accent);
  padding: 14px 18px;
  border-radius: 0 var(--radius) var(--radius) 0;
  color: var(--muted);
  margin: 24px 0;
}

/* ---------- Tablets and phones: stack the two columns ---------- */

@media (max-width: 900px) {
  .layout {
    grid-template-columns: 1fr;
    gap: 48px;
    padding: 40px 24px;
  }

  .sidebar {
    position: static;
  }

  .photo {
    max-width: 180px;
  }

  .side-nav {
    flex-direction: row;
    flex-wrap: wrap;
    gap: 6px 20px;
  }
}

/* ---------- Small screens ---------- */

@media (max-width: 680px) {
  body {
    font-size: 16px;
  }

  .site-header {
    position: static;
  }

  .site-header .container {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
    padding-top: 16px;
    padding-bottom: 16px;
  }

  .section {
    padding: 48px 0;
  }

  .entry {
    grid-template-columns: 1fr;
  }

  .entry .date {
    margin-bottom: 8px;
  }

  .skills {
    grid-template-columns: 1fr;
    gap: 2px;
  }

  .area-cards,
  .columns-2 {
    grid-template-columns: 1fr;
  }

  .skills dd {
    margin-bottom: 12px;
  }
}

/* ==========================================================================
   Wide project pages ("wide: true" in a project's index.md)
   Full-width layout: title beside the cover photo, an "On this page" menu,
   and photos placed beside their text.
   ========================================================================== */

.wide-page {
  --width-wide: 1320px;
}

.wide-page .site-header .container,
.wide-page .site-footer .container {
  max-width: var(--width-wide);
}

.article.wide {
  max-width: var(--width-wide);
  padding: 32px 40px 80px;
}

/* Title and details on the left, cover photo on the right */
.wide .article-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 48px;
  align-items: center;
  padding-bottom: 40px;
  border-bottom: 1px solid var(--border);
}

.wide .article-head h1 {
  font-size: clamp(2rem, 3.2vw, 2.8rem);
  line-height: 1.15;
  margin: 12px 0 16px;
}

.wide .article-head .meta {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px 24px;
  border-bottom: none;
}

.wide .article-head .cover {
  margin: 0;
  max-height: 460px;
  object-fit: cover;
}

/* Menu on the left, content on the right */
.article-body {
  display: grid;
  grid-template-columns: 220px minmax(0, 1fr);
  gap: 56px;
  margin-top: 8px;
}

.toc {
  position: sticky;
  top: 88px;
  align-self: start;
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding-top: 48px;
  font-size: 14px;
}

.toc-title {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 8px;
}

.toc a {
  color: var(--muted);
  padding: 5px 0 5px 12px;
  border-left: 2px solid var(--border);
}

.toc a:hover {
  color: var(--accent);
  border-left-color: var(--accent);
  text-decoration: none;
}

.prose h2 {
  scroll-margin-top: 88px;
  padding-top: 8px;
}

.prose h2:first-child {
  margin-top: 48px;
}

/* Photo (or video) beside its text. Add "reverse" to put the photo on the right. */
.split {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 40px;
  align-items: center;
  margin: 32px 0;
}

.split.reverse > :first-child {
  order: 2;
}

.split > * > :first-child {
  margin-top: 0;
}

.split > * > :last-child {
  margin-bottom: 0;
}

.split h3 {
  margin-top: 0;
}

/* Small photo + text, used for links to related projects */
.split.compact {
  grid-template-columns: 220px minmax(0, 1fr);
  gap: 28px;
}

.wide .split.compact figure img {
  aspect-ratio: 1;
}

/* Two blocks of text or tables side by side, aligned at the top */
.columns {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 40px;
  align-items: start;
  margin: 24px 0;
}

.columns > * > :first-child {
  margin-top: 0;
}

/* Code shown beside text: slightly smaller so typical lines fit */
.columns pre {
  font-size: 13px;
}

/* Boxed panel, used for "the problem / the solution" and settings */
.panel {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 24px;
  background: var(--bg-soft);
}

.panel h3,
.panel h4 {
  margin: 0 0 10px;
}

/* Photos in a row, each with its caption */
.gallery {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
  margin: 24px 0;
}

.wide figure {
  margin: 0;
}

.wide figure img,
.wide figure video {
  width: 100%;
  max-height: none;
  margin: 0;
  object-fit: cover;
}

/* Photos and a phone video in one row, all the same height.
   Column widths match the shapes: 3:4 photos, 9:16 video. */
.media-row {
  display: grid;
  grid-template-columns: 4fr 4fr 3fr;
  gap: 20px;
  margin: 24px 0;
}

.media-row img,
.media-row video {
  aspect-ratio: 3 / 4;
}

.media-row .tall video {
  aspect-ratio: 9 / 16;
  background: #000;
  object-fit: contain;
}

.panel > :first-child {
  margin-top: 0;
}

.panel > :last-child {
  margin-bottom: 0;
}

.wide .split figure img {
  max-height: 520px;
}

.wide .panel table {
  background: var(--bg);
}

/* Tables fill their column on big screens (they scroll sideways on phones) */
@media (min-width: 801px) {
  .wide table {
    display: table;
  }
}

.wide figcaption {
  text-align: left;
}

@media (max-width: 1000px) {
  .article-body {
    grid-template-columns: minmax(0, 1fr);
    gap: 0;
  }

  .toc {
    display: none;
  }
}

@media (max-width: 800px) {
  .article.wide {
    padding: 32px 20px 64px;
  }

  .wide .article-head,
  .split,
  .split.compact,
  .columns {
    grid-template-columns: minmax(0, 1fr);
    gap: 24px;
  }

  .wide .article-head .head-media {
    order: -1;
  }

  .split.reverse > :first-child {
    order: 0;
  }

  .media-row {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  }

  .media-row .tall {
    grid-column: 1 / -1;
    max-width: 320px;
  }
}

.wide h4 {
  font-size: 1.05rem;
  margin: 28px 0 12px;
}