/* ==========================================================================
   Computational Portfolio — single stylesheet
   Layer order: tokens, reset/base, layout primitives, components,
   responsive refinements, motion and contrast overrides.
   ========================================================================== */

/* ------------------------------ 1. TOKENS ------------------------------- */

:root {
  --color-bg: #ffffff;
  --color-surface: #f4f6fb;
  --color-text: #111827;
  --color-muted: #4b5563;
  --color-accent: #1d4ed8;
  --color-accent-contrast: #ffffff;
  --color-border: #7d8896;
  --color-hairline: #dde3ec;
  --color-shadow: 15 23 42;

  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 3rem;
  --space-8: 4.5rem;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;

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

  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.5rem;
  --text-3xl: clamp(2rem, 1.4rem + 2.6vw, 3.25rem);

  --shadow-1: 0 1px 2px rgb(var(--color-shadow) / 0.06),
    0 1px 3px rgb(var(--color-shadow) / 0.08);
  --shadow-2: 0 4px 12px rgb(var(--color-shadow) / 0.07),
    0 12px 28px rgb(var(--color-shadow) / 0.08);

  --container: 68rem;
  --header-h: 4rem;
  --speed: 180ms;
}

[data-theme="dark"] {
  --color-bg: #0b1120;
  --color-surface: #131d33;
  --color-text: #e8eefb;
  --color-muted: #a8b6cf;
  --color-accent: #7dabff;
  --color-accent-contrast: #0b1120;
  --color-border: #64748b;
  --color-hairline: #232f4a;
  --color-shadow: 0 0 0;
}

/* --------------------------- 2. RESET / BASE --------------------------- */

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

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

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

h1,
h2,
h3 {
  margin: 0 0 var(--space-3);
  line-height: 1.2;
  font-weight: 700;
  letter-spacing: -0.015em;
}

h1 {
  font-size: var(--text-3xl);
}

h2 {
  font-size: var(--text-xl);
}

h3 {
  font-size: var(--text-lg);
}

p {
  margin: 0 0 var(--space-4);
}

ul,
ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

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

img {
  height: auto;
}

a {
  color: var(--color-accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
}

a:hover {
  text-decoration-thickness: 2px;
}

:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

::selection {
  background: var(--color-accent);
  color: var(--color-accent-contrast);
}

/* ------------------------ 3. LAYOUT PRIMITIVES ------------------------- */

.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--space-5);
}

.main {
  display: block;
}

.main:focus {
  outline: none;
}

.section {
  padding-block: var(--space-8);
  scroll-margin-top: var(--header-offset, calc(var(--header-h) + 1rem));
}

.section--alt {
  background: var(--color-surface);
}

.section__title {
  margin-bottom: var(--space-5);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  top: var(--space-2);
  left: var(--space-2);
  z-index: 100;
  padding: var(--space-2) var(--space-4);
  background: var(--color-accent);
  color: var(--color-accent-contrast);
  border-radius: var(--radius-sm);
  font-weight: 600;
  text-decoration: none;
  transform: translateY(-200%);
}

.skip-link:focus {
  transform: translateY(0);
}

/* ---------------------------- 4. COMPONENTS ---------------------------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 0.7em 1.3em;
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  font: inherit;
  font-weight: 600;
  line-height: 1.2;
  text-decoration: none;
  cursor: pointer;
  transition: background-color var(--speed) ease, color var(--speed) ease,
    border-color var(--speed) ease, transform var(--speed) ease;
}

.btn--primary {
  background: var(--color-accent);
  color: var(--color-accent-contrast);
}

.btn--primary:hover {
  background: color-mix(in srgb, var(--color-accent) 85%, black);
}

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

.btn--ghost:hover {
  background: var(--color-surface);
}

.btn--quiet {
  padding-inline: 0;
  color: var(--color-accent);
  font-weight: 600;
  text-decoration: underline;
}

.badge {
  display: inline-block;
  padding: 0.15em 0.65em;
  border: 1px solid var(--color-hairline);
  border-radius: 999px;
  background: var(--color-bg);
  color: var(--color-muted);
  font-size: var(--text-sm);
  line-height: 1.7;
  white-space: nowrap;
}

.badges {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.card {
  display: flex;
  flex-direction: column;
  padding: var(--space-5);
  border: 1px solid var(--color-hairline);
  border-radius: var(--radius-lg);
  background: var(--color-bg);
  box-shadow: var(--shadow-1);
}

.cards {
  display: grid;
  gap: var(--space-5);
}

.cards--3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.cards--4 {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

/* -- header -- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--color-bg) 82%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--speed) ease;
}

.site-header.is-scrolled {
  border-bottom-color: var(--color-hairline);
}

.site-header__inner {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  min-height: var(--header-h);
}

.site-header__brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-weight: 700;
  color: var(--color-text);
  text-decoration: none;
  white-space: nowrap;
}

.site-header__controls {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-left: auto;
}

.lang-group {
  display: flex;
  padding: 2px;
  border: 1px solid var(--color-hairline);
  border-radius: 999px;
  background: var(--color-surface);
}

.lang-group button {
  padding: 0.15em 0.6em;
  border: 0;
  border-radius: 999px;
  background: transparent;
  color: var(--color-muted);
  font: inherit;
  font-size: var(--text-sm);
  font-weight: 600;
  cursor: pointer;
  transition: background-color var(--speed) ease, color var(--speed) ease;
}

.lang-group button[aria-pressed="true"] {
  background: var(--color-accent);
  color: var(--color-accent-contrast);
}

.theme-toggle {
  display: grid;
  place-items: center;
  width: 2.4rem;
  height: 2.4rem;
  padding: 0;
  border: 1px solid var(--color-hairline);
  border-radius: 50%;
  background: var(--color-surface);
  color: var(--color-text);
  cursor: pointer;
  transition: background-color var(--speed) ease;
}

.theme-toggle:hover {
  background: var(--color-surface);
  border-color: var(--color-border);
}

.theme-toggle svg {
  grid-area: 1 / 1;
  width: 1.15rem;
  height: 1.15rem;
}

.theme-toggle__moon {
  display: none;
}

[data-theme="dark"] .theme-toggle__sun {
  display: none;
}

[data-theme="dark"] .theme-toggle__moon {
  display: block;
}

  .nav-toggle {
    display: none;
    width: 2.4rem;
    height: 2.4rem;
    padding: 0;
    border: 1px solid var(--color-hairline);
    border-radius: var(--radius-sm);
    background: var(--color-surface);
    color: var(--color-text);
    cursor: pointer;
  }

.nav-toggle__bars,
.nav-toggle__bars::before,
.nav-toggle__bars::after {
  display: block;
  width: 1.1rem;
  height: 2px;
  margin-inline: auto;
  background: currentColor;
  border-radius: 2px;
}

.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: relative;
}

.nav-toggle__bars::before {
  top: -6px;
}

.nav-toggle__bars::after {
  top: 4px;
}

.site-nav__list {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.site-nav__list a {
  position: relative;
  padding-block: var(--space-1);
  color: var(--color-muted);
  font-weight: 500;
  text-decoration: none;
}

.site-nav__list a:hover {
  color: var(--color-text);
}

.site-nav__list a[aria-current="true"] {
  color: var(--color-text);
  font-weight: 700;
}

.site-nav__list a[aria-current="true"]::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -2px;
  height: 2px;
  background: var(--color-accent);
}

/* -- hero -- */

.hero {
  position: relative;
  padding-block: var(--space-8) var(--space-7);
  overflow: hidden;
  scroll-margin-top: var(--header-offset, calc(var(--header-h) + 1rem));
}

.hero__backdrop {
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    radial-gradient(60rem 30rem at 15% -10%,
      color-mix(in srgb, var(--color-accent) 16%, transparent), transparent 60%),
    radial-gradient(45rem 28rem at 95% 0%,
      color-mix(in srgb, var(--color-accent) 9%, transparent), transparent 55%),
    repeating-linear-gradient(to right,
      color-mix(in srgb, var(--color-text) 5%, transparent) 0 1px, transparent 1px 32px),
    repeating-linear-gradient(to bottom,
      color-mix(in srgb, var(--color-text) 5%, transparent) 0 1px, transparent 1px 32px);
}

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

.hero__availability {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
  padding: 0.3em 0.9em;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  color: var(--color-muted);
  font-size: var(--text-sm);
  font-weight: 500;
}

.dot {
  width: 0.5rem;
  height: 0.5rem;
  border-radius: 50%;
  background: var(--color-accent);
}

.hero__name {
  margin-bottom: var(--space-2);
}

.hero__role {
  margin-bottom: var(--space-4);
  color: var(--color-muted);
  font-size: var(--text-lg);
  font-weight: 500;
}

.hero__intro {
  max-width: 44ch;
  color: var(--color-muted);
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  align-items: center;
  margin-top: var(--space-5);
}

/* -- about -- */

.about {
  display: grid;
  grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr);
  gap: var(--space-6);
  align-items: start;
}

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

.stats {
  display: grid;
  gap: var(--space-3);
  margin: 0;
  padding: var(--space-5);
  border: 1px solid var(--color-hairline);
  border-radius: var(--radius-lg);
  background: var(--color-surface);
}

.stats__item {
  color: var(--color-muted);
  font-weight: 600;
}

/* -- skills -- */

.skill {
  gap: var(--space-3);
}

.skill__title {
  order: 2;
  margin: 0;
}

.skill__icon {
  order: 1;
  width: 1.75rem;
  height: 1.75rem;
  color: var(--color-accent);
}

.skill__desc {
  order: 3;
  margin: 0;
  color: var(--color-muted);
  font-size: var(--text-sm);
}

.skill .badges {
  order: 4;
  margin-top: auto;
  padding-top: var(--space-2);
}

[hidden] {
  display: none !important;
}

/* -- project -- */

.project {
  padding: 0;
  overflow: hidden;
}

.project__media {
  width: 100%;
  aspect-ratio: 16 / 9;
  /* The six cards mix real photographs (1:1, 1.26, 1.87) with the SVG
   * placeholders (16:9). A fixed box plus cover keeps the row aligned whatever
   * the source aspect ratio is, instead of leaving ragged card tops. */
  object-fit: cover;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-hairline);
}

.project__body {
  display: flex;
  flex-direction: column;
  flex: 1;
  gap: var(--space-3);
  padding: var(--space-5);
}

.project__body p {
  margin: 0;
}

.project__text {
  color: var(--color-muted);
  font-size: var(--text-sm);
}

.project__links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  margin-top: auto;
  padding-top: var(--space-2);
  font-size: var(--text-sm);
  font-weight: 600;
}

/* Institutional attribution on work that has no public link. Sits in the footer
 * slot so the card keeps its links-or-note aligned across the grid. */
.project__note {
  margin-top: auto;
  padding-top: var(--space-2);
  color: var(--color-muted);
  font-size: var(--text-sm);
}

/* -- research -- */

.entries {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-5);
}

.entry__title {
  margin-bottom: var(--space-1);
}

.entry__meta {
  margin-bottom: var(--space-3);
  color: var(--color-muted);
  font-size: var(--text-sm);
}

.entry__abstract {
  color: var(--color-muted);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.entry__actions {
  margin: 0;
  margin-top: auto;
}

/* Stands in for a download button on work that cannot be shared, so the reader
 * is told why there is no link rather than left wondering. */
.entry__note {
  margin-top: auto;
  padding-top: var(--space-3);
  color: var(--color-muted);
  font-size: var(--text-sm);
  font-style: italic;
}

/* -- contact -- */

.contact__lead {
  max-width: 50ch;
  color: var(--color-muted);
}

.contact {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.4fr);
  gap: var(--space-6);
  align-items: start;
}

.contact__aside {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  align-items: flex-start;
}

.contact__social {
  display: flex;
  gap: var(--space-4);
  margin: 0;
}

.contact__form {
  display: grid;
  gap: var(--space-4);
}

.field {
  display: grid;
  gap: var(--space-2);
}

.field label {
  font-size: var(--text-sm);
  font-weight: 600;
}

.field input,
.field textarea {
  width: 100%;
  padding: 0.65em 0.85em;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg);
  color: var(--color-text);
  font: inherit;
}

.field textarea {
  resize: vertical;
}

.field :is(input, textarea):focus-visible {
  border-color: var(--color-accent);
}

/* -- legal pages -- */

.legal {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-5);
  margin-bottom: var(--space-6);
}

.legal h2 {
  font-size: var(--text-base);
  letter-spacing: 0;
}

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

/* -- footer -- */

.site-footer {
  padding-block: var(--space-6);
  border-top: 1px solid var(--color-hairline);
  background: var(--color-surface);
}

.site-footer__inner {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  align-items: center;
  justify-content: space-between;
}

.site-footer__copy {
  margin: 0;
  color: var(--color-muted);
  font-size: var(--text-sm);
}

.site-footer__nav {
  display: flex;
  gap: var(--space-4);
}

/* ------------------- 5. RESPONSIVE REFINEMENTS ------------------------ */

@media (max-width: 60rem) {
  .cards--4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .cards--3 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

  .about,
  .contact,
  .legal {
    grid-template-columns: minmax(0, 1fr);
  }
}

@media (max-width: 54rem) {
  :root {
    --header-h: 3.5rem;
  }

  .site-header__brand {
    order: 1;
    /* Let the brand truncate rather than grow, so the row never overflows. */
    min-width: 0;
  }

  /* The hamburger only works with JS, so it stays hidden without it, and it
   * only exists at all in the narrow layout. */
  .js .nav-toggle {
    display: block;
    order: 3;
  }

  .site-header__brand span:last-child {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .site-header__controls {
    order: 2;
    margin-left: auto;
    margin-right: var(--space-2);
  }

  /* Without JS the menu cannot be collapsed, so the default is expanded and
   * only a JS-enabled page opts into the disclosure. This keeps the in-page
   * navigation working at every width with scripting disabled, instead of
   * leaving a permanently dead hamburger button. */
  .site-nav {
    order: 4;
    display: block;
    width: 100%;
    padding-block: var(--space-3);
    border-top: 1px solid var(--color-hairline);
  }

  .js .site-nav {
    display: none;
  }

  .js .site-nav.is-open {
    display: block;
  }

  .site-header__inner {
    flex-wrap: wrap;
  }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .site-nav__list a {
    display: block;
    padding: var(--space-3) 0;
    border-bottom: 1px solid var(--color-hairline);
  }

  .site-nav__list a[aria-current="true"]::after {
    left: 0;
    right: auto;
    width: 3px;
    top: 0;
    bottom: 0;
    height: auto;
  }
}

@media (max-width: 30rem) {
  .container {
    padding-inline: var(--space-4);
  }

  .cards--3,
  .cards--4,
  .stats {
    grid-template-columns: minmax(0, 1fr);
  }

  .hero__actions .btn {
    width: 100%;
  }

  .site-footer__inner {
    flex-direction: column;
    align-items: flex-start;
  }
}

/* --------------- 6. MOTION AND CONTRAST OVERRIDES --------------------- */

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

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}

@media (prefers-contrast: more) {
  :root {
    --color-muted: #374151;
    --color-border: #5f6d80;
    --color-hairline: #7d8896;
  }

  [data-theme="dark"] {
    --color-muted: #dbe4f5;
    --color-border: #9aa9c2;
    --color-hairline: #748399;
  }

  :focus-visible {
    outline-width: 3px;
  }
}