/* =========================================================
   Aditya Bikram Thakur, portfolio
   Plain CSS shared by every page. No build step.
   Colors are tokens at the top: change one and the whole site follows,
   in both light and dark mode.
   ========================================================= */

/* Italic serif for the "tech stack" lines: KaTeX's Computer Modern, the font of math papers. */
@font-face {
  font-family: "KaTeX_Main";
  font-style: italic;
  font-weight: 400;
  font-display: swap;
  src: url("https://cdnjs.cloudflare.com/ajax/libs/KaTeX/0.16.9/fonts/KaTeX_Main-Italic.woff2") format("woff2");
}

/* ---------- Color tokens: light ---------- */
:root {
  --background: #ffffff;
  --foreground: #0a0a0a;
  --card: #ffffff;
  --muted: #f5f5f5;
  --muted-foreground: #6e6e6e;
  --border: #e5e5e5;
  --nav-bg: rgba(255, 255, 255, 0.8);
  --dot: 10, 10, 10;        /* pixel background color, as R, G, B */
  --dot-alpha: 0.2;

  --sans: "Geist", ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "Geist Mono", ui-monospace, "SF Mono", Menlo, monospace;
  --math: "KaTeX_Main", "Latin Modern Roman", "Iowan Old Style", Georgia, serif;

  color-scheme: light;
}

/* ---------- Color tokens: dark ---------- */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --background: #151618;
    --foreground: #dedede;
    --card: #1c1d1f;
    --muted: #232426;
    --muted-foreground: #9e9e9e;
    --border: rgba(255, 255, 255, 0.08);
    --nav-bg: rgba(21, 22, 24, 0.8);
    --dot: 222, 222, 222;
    --dot-alpha: 0.24;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --background: #151618;
  --foreground: #dedede;
  --card: #1c1d1f;
  --muted: #232426;
  --muted-foreground: #9e9e9e;
  --border: rgba(255, 255, 255, 0.08);
  --nav-bg: rgba(21, 22, 24, 0.8);
  --dot: 222, 222, 222;
  --dot-alpha: 0.24;
  color-scheme: dark;
}

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

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

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--background);
  color: var(--foreground);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

h1, h2, h3, p, figure, ul, ol { margin: 0; }
img { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
::selection { background: var(--foreground); color: var(--background); }

a:focus-visible, button:focus-visible, [tabindex]:focus-visible {
  outline: 2px solid var(--foreground);
  outline-offset: 3px;
  border-radius: 4px;
}

.container {
  width: 100%;
  max-width: 768px;
  margin-inline: auto;
  padding-inline: 24px;
}
@media (min-width: 768px) { .container { padding-inline: 32px; } }

.skip-link {
  position: absolute;
  left: 12px;
  top: -48px;
  z-index: 100;
  padding: 8px 14px;
  border-radius: 6px;
  background: var(--foreground);
  color: var(--background);
  font-size: 14px;
}
.skip-link:focus { top: 12px; }

/* ---------- Header ---------- */
.site-header {
  position: relative;
  z-index: 2; /* above the pixel background */
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-block: 32px;
}

.wordmark {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.35em;
}

.header-nav { display: flex; align-items: center; gap: 24px; }

.nav-links {
  display: none;
  gap: 24px;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.25em;
  text-transform: uppercase;
}
@media (min-width: 768px) { .nav-links { display: flex; } }

.nav-links a { color: var(--muted-foreground); transition: color 0.2s ease; }
.nav-links a:hover, .nav-links a[aria-current="page"] { color: var(--foreground); }

.theme-btn {
  display: flex;
  align-items: center;
  padding: 0;
  border: 0;
  background: none;
  color: var(--muted-foreground);
  cursor: pointer;
  transition: color 0.2s ease;
}
.theme-btn:hover { color: var(--foreground); }
.theme-btn svg { width: 16px; height: 16px; }
.theme-btn svg:not(.on) { display: none; }

.icon {
  fill: none;
  stroke: currentColor;
  stroke-width: 1.6;
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* ---------- Main ---------- */
main {
  flex-grow: 1;
  width: 100%;
  padding-top: 64px;
  padding-bottom: 112px; /* room for the phone tab bar */
}
@media (min-width: 768px) { main { padding-bottom: 96px; } }

.page { position: relative; z-index: 1; }

.page-title {
  font-size: 30px;
  font-weight: 600;
  letter-spacing: -0.025em;
  line-height: 1.2;
}
.page-head { margin-bottom: 40px; }

.section { margin-top: 72px; }
.section-title {
  margin-bottom: 28px;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  color: var(--muted-foreground);
}

/* ---------- About (home) ---------- */
.name {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 4px 14px;
  font-size: 36px;
  font-weight: 600;
  letter-spacing: -0.025em;
  line-height: 1.15;
  text-align: center;
}
@media (min-width: 640px) { .name { font-size: 48px; } }
@media (min-width: 768px) { .name { justify-content: flex-start; text-align: left; } }

.name-links { display: inline-flex; gap: 12px; }
.name-links a { color: var(--muted-foreground); transition: color 0.2s ease; }
.name-links a:hover { color: var(--foreground); }
.name-links svg { width: 26px; height: 26px; fill: currentColor; }
@media (min-width: 640px) { .name-links svg { width: 30px; height: 30px; } }

.figure { margin-top: 40px; }
.figure-frame {
  position: relative;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: var(--muted);
}
.figure-frame img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.figure figcaption {
  margin-top: 10px;
  font-size: 14px;
  line-height: 1.6;
  text-align: center;
  color: var(--muted-foreground);
  opacity: 0.85;
}

/* Shown until a real photo is dropped into assets/ */
.figure-empty {
  display: none;
  position: absolute;
  inset: 0;
  place-items: center;
  border: 1px dashed var(--border);
  color: var(--muted-foreground);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  text-align: center;
  padding: 16px;
}
.figure-frame.is-empty img { display: none; }
.figure-frame.is-empty .figure-empty { display: grid; }

.bio {
  margin-top: 40px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--muted-foreground);
}
.bio p + p { margin-top: 24px; }

/* Dashed-underline phrases. They link somewhere and show a note on hover. */
.term {
  text-decoration: underline dashed;
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
  transition: color 0.2s ease;
}
.term:hover, .term:focus-visible { color: var(--foreground); }

.bio .plain-link {
  color: var(--foreground);
  text-decoration: underline;
  text-underline-offset: 4px;
  text-decoration-thickness: 1px;
}

.status {
  display: inline-flex;
  align-items: center;
  gap: 10px;
}
.status::before {
  content: "";
  width: 7px;
  height: 7px;
  flex: none;
  border-radius: 50%;
  background: #3fa66b;
  box-shadow: 0 0 0 3px rgba(63, 166, 107, 0.18);
}

/* Floating note for .term (built by site.js) */
.tip {
  position: fixed;
  z-index: 60;
  max-width: min(300px, calc(100vw - 16px));
  padding: 8px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--card);
  color: var(--foreground);
  font-size: 13px;
  line-height: 1.5;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.18);
  pointer-events: none;
  opacity: 0;
  transform: translateY(4px);
  transition: opacity 0.15s ease, transform 0.15s ease;
}
.tip.show { opacity: 1; transform: none; }

/* ---------- Entries (projects, experience, education) ---------- */
.entries > * + * { margin-top: 48px; }

.entry { scroll-margin-top: 24px; }

.entry-head {
  display: flex;
  flex-direction: column;
  gap: 6px;
}
@media (min-width: 768px) {
  .entry-head { flex-direction: row; align-items: baseline; justify-content: space-between; gap: 24px; }
}
.entry-title {
  font-size: 18px;
  font-weight: 600;
  line-height: 1.4;
}
.entry-title .sub { font-weight: 400; color: var(--muted-foreground); }
.entry-date {
  flex: none;
  font-size: 12px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--muted-foreground);
}

.stack {
  margin-top: 8px;
  font-family: var(--math);
  font-style: italic;
  font-size: 16px;
  color: var(--muted-foreground);
}

.entry .figure { margin-top: 20px; }
.entry .figure figcaption { text-align: left; }

.bullets {
  margin-top: 14px;
  padding-left: 20px;
  list-style: disc;
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted-foreground);
}
.bullets li + li { margin-top: 4px; }
.bullets li::marker { color: var(--muted-foreground); }

.entry-note + .entry-note { margin-top: 2px; }
.entry-note {
  margin-top: 6px;
  font-size: 14px;
  color: var(--muted-foreground);
}

.entry-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 22px;
  margin-top: 16px;
}
.entry-links a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  font-weight: 500;
  text-decoration: underline;
  text-underline-offset: 4px;
  text-decoration-thickness: 1px;
  transition: color 0.2s ease;
}
.entry-links a:hover { color: var(--muted-foreground); }
.entry-links svg { width: 14px; height: 14px; }


/* ---------- Contact ---------- */
.contact-intro {
  max-width: 56ch;
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted-foreground);
}
.channels {
  list-style: none;
  padding: 0;
  margin-top: 32px;
}
.channels li + li { margin-top: 20px; }
.channels a {
  display: inline-flex;
  flex-direction: column;
  gap: 4px;
  transition: color 0.2s ease;
}
.channels a:hover { color: var(--muted-foreground); }
.channel-label {
  font-size: 12px;
  letter-spacing: 0.25em;
  text-transform: uppercase;
  color: var(--muted-foreground);
}
.channel-value {
  font-size: 16px;
  font-weight: 500;
  letter-spacing: 0.02em;
  overflow-wrap: anywhere;
}

/* ---------- Phone tab bar ---------- */
.tabbar {
  position: fixed;
  inset-inline: 0;
  bottom: 0;
  z-index: 50;
  border-top: 1px solid var(--border);
  background: var(--nav-bg);
  -webkit-backdrop-filter: blur(16px);
  backdrop-filter: blur(16px);
  padding-bottom: env(safe-area-inset-bottom);
}
@media (min-width: 768px) { .tabbar { display: none; } }

.tabbar ul {
  display: flex;
  max-width: 768px;
  margin-inline: auto;
  padding: 0;
  list-style: none;
}
.tabbar li { flex: 1; }
.tabbar a {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  min-height: 56px;
  padding-block: 8px;
  color: var(--muted-foreground);
  font-size: 10px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  transition: color 0.2s ease;
}
.tabbar a[aria-current="page"], .tabbar a:hover { color: var(--foreground); }
.tabbar svg { width: 22px; height: 22px; }

/* ---------- Pixel background ---------- */
/* Each page places one or two of these. pixels.js draws into them. */
.pixels {
  position: fixed;
  z-index: 0;
  pointer-events: none;
  overflow: hidden;
}
.pixels canvas { display: block; width: 100%; height: 100%; }

.pixels--top {
  inset-inline: 0;
  top: 0;
  height: 50vh;
  -webkit-mask-image: linear-gradient(to bottom, #000 35%, transparent);
  mask-image: linear-gradient(to bottom, #000 35%, transparent);
}
.pixels--bottom {
  inset-inline: 0;
  bottom: 0;
  height: 50vh;
  -webkit-mask-image: linear-gradient(to top, #000 72%, transparent);
  mask-image: linear-gradient(to top, #000 72%, transparent);
}
.pixels--left, .pixels--right {
  top: 0;
  bottom: 0;
  width: 25%;
  display: none;
}
.pixels--left {
  left: 0;
  -webkit-mask-image: linear-gradient(to right, #000 30%, transparent);
  mask-image: linear-gradient(to right, #000 30%, transparent);
}
.pixels--right {
  right: 0;
  -webkit-mask-image: linear-gradient(to left, #000 30%, transparent);
  mask-image: linear-gradient(to left, #000 30%, transparent);
}
@media (min-width: 1100px) {
  .pixels--left, .pixels--right { display: block; }
}

/* A figure that keeps the image's own shape instead of 16:9 */
.figure-frame--auto { aspect-ratio: auto; background: none; }
.figure-frame--auto img { position: static; height: auto; }

/* Website screenshots get a hairline border, so a white page doesn't melt into a white background */
.figure-frame--shot img {
  border: 1px solid var(--border);
  border-radius: 8px;
}

.figure-frame--shot { border-radius: 8px; background: none; }


/* Certificates: image cards that open the official verification page */
.cert-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 28px 20px;
  padding: 0;
  list-style: none;
}
.cert-grid li { display: flex; }
.cert-card { display: flex; flex-direction: column; gap: 4px; flex: 1; }
.cert-card img {
  width: 100%;
  height: auto;
  margin-bottom: 10px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: #fff;
  transition: transform 0.2s ease, border-color 0.2s ease;
}
.cert-card:hover img { transform: translateY(-3px); border-color: var(--muted-foreground); }
.cert-name { font-size: 14px; font-weight: 500; line-height: 1.4; }
.cert-meta { font-size: 12px; line-height: 1.5; color: var(--muted-foreground); }
.cert-verify {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: auto;
  padding-top: 6px;
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--muted-foreground);
  transition: color 0.2s ease;
}
.cert-card:hover .cert-verify { color: var(--foreground); }
.cert-verify svg { width: 12px; height: 12px; }