/* Site styles for avtarfr.github.io
   Dark theme is the default; [data-theme="light"] overrides the color tokens.
   Fonts are loaded from Google Fonts in _includes/head.html. */

:root, [data-theme="dark"] {
  color-scheme: dark;
  --bg: #151913;
  --bg-alt: #1A2017;
  --surface: #21281E;
  --surface-raised: #2A3326;
  --inset-bg: #10140E;
  --border: #364231;
  --border-soft: #2B3427;
  --border-focus: #9DB56E;

  --text-bright: #F5EFEB;
  --text: #E0D8CE;
  --text-muted: #A3B38D;

  --accent: #88A059;
  --accent-text: #B8CC8F;
  --accent-contrast: #11160C;
  --accent-hover: #A5BC74;
  --accent-light: rgba(136, 160, 89, 0.14);
  --accent-badge-border: rgba(136, 160, 89, 0.55);
  --glow: rgba(136, 160, 89, 0.10);

  --header-bg: rgba(21, 25, 19, 0.82);
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.25);
  --shadow-md: 0 10px 30px -12px rgba(0, 0, 0, 0.55);

  --font-sans: "Plus Jakarta Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;

  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 10px;
  --ease: cubic-bezier(0.2, 0.7, 0.2, 1);
}

[data-theme="light"] {
  color-scheme: light;
  --bg: #F5F3EF;
  --bg-alt: #ECE8E1;
  --surface: #FFFFFF;
  --surface-raised: #F0EBE3;
  --inset-bg: #EFEAE2;
  --border: #D8D0C3;
  --border-soft: #E4DDD2;
  --border-focus: #5E733B;

  --text-bright: #1F2617;
  --text: #35402B;
  --text-muted: #56664A;

  --accent: #5E733B;
  --accent-text: #495B2D;
  --accent-contrast: #FFFFFF;
  --accent-hover: #405027;
  --accent-light: #E9EFE0;
  --accent-badge-border: #A9B892;
  --glow: rgba(94, 115, 59, 0.08);

  --header-bg: rgba(245, 243, 239, 0.85);
  --shadow-sm: 0 1px 2px rgba(31, 38, 23, 0.06);
  --shadow-md: 0 12px 28px -14px rgba(31, 38, 23, 0.22);
}

/* Base */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 5.5rem;
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  background-color: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 0.95rem;
  line-height: 1.68;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: clip;
  width: 100%;
}

main {
  flex: 1 0 auto;
}

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

h1, h2, h3, h4 {
  font-family: var(--font-sans);
  font-weight: 700;
  color: var(--text-bright);
  text-wrap: balance;
}

p {
  text-wrap: pretty;
}

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

a {
  color: var(--accent-text);
  text-decoration: none;
  transition: color 0.15s ease;
}

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

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

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

.skip-link {
  position: absolute;
  left: 1rem;
  top: -100px;
  z-index: 200;
  background: var(--accent);
  color: var(--accent-contrast);
  font-weight: 600;
  font-size: 0.88rem;
  padding: 0.55rem 1rem;
  border-radius: var(--radius-md);
}

.skip-link:focus {
  top: 0.75rem;
  color: var(--accent-contrast);
}

.container {
  width: 100%;
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

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

/* Header & Navigation */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--header-bg);
  backdrop-filter: saturate(140%) blur(12px);
  -webkit-backdrop-filter: saturate(140%) blur(12px);
  border-bottom: 1px solid var(--border-soft);
}

.nav-container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0.7rem 1.5rem;
  display: flex;
  align-items: center;
  gap: 1.2rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 700;
  font-size: 1rem;
  color: var(--text-bright);
  white-space: nowrap;
  min-width: 0;
}

.brand:hover {
  color: var(--text-bright);
}

.brand-mark {
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  border-radius: 7px;
  display: grid;
  place-items: center;
  background: var(--accent);
  color: var(--accent-contrast);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.brand-name {
  overflow: hidden;
  text-overflow: ellipsis;
}

.site-nav {
  margin-left: auto;
  min-width: 0;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.2rem;
  list-style: none;
}

.nav-links a {
  display: block;
  font-size: 0.86rem;
  font-weight: 500;
  color: var(--text-muted);
  padding: 0.3rem 0.65rem;
  border-radius: var(--radius-md);
  transition: color 0.15s ease, background-color 0.15s ease;
}

.nav-links a:hover {
  color: var(--text-bright);
  background: var(--accent-light);
}

.nav-links a[aria-current] {
  color: var(--text-bright);
  background: var(--accent-light);
}

.theme-toggle-btn {
  flex-shrink: 0;
  width: 34px;
  height: 34px;
  display: inline-grid;
  place-items: center;
  background: var(--surface-raised);
  border: 1px solid var(--border);
  color: var(--text-bright);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: border-color 0.15s ease, background-color 0.15s ease;
}

.theme-toggle-btn:hover {
  border-color: var(--border-focus);
}

.theme-toggle-btn svg {
  width: 16px;
  height: 16px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

/* Show the icon for the theme the button switches to */
[data-theme="dark"] .icon-moon,
[data-theme="light"] .icon-sun {
  display: none;
}

/* Sections */
.section {
  padding: 4.5rem 0;
}

.section-alt {
  background-color: var(--bg-alt);
  border-top: 1px solid var(--border-soft);
  border-bottom: 1px solid var(--border-soft);
}

.section-alt + .section-alt {
  border-top: none;
}

.section-head {
  margin-bottom: 2.2rem;
}

.section-headline {
  font-size: 1.75rem;
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin-bottom: 0.55rem;
}

.section-subtitle {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.6;
  max-width: 62ch;
}

/* Hero */
.hero-section {
  position: relative;
  padding: 5rem 0 4.5rem;
  isolation: isolate;
}

.hero-section::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(600px 320px at 85% 10%, var(--glow), transparent 70%),
    radial-gradient(480px 280px at 0% 100%, var(--glow), transparent 70%);
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 260px;
  gap: 3.5rem;
  align-items: center;
}

.hero-content {
  min-width: 0;
}

.hero-name {
  font-size: clamp(2.1rem, 1.4rem + 2.6vw, 3.1rem);
  letter-spacing: -0.03em;
  line-height: 1.08;
  margin-bottom: 0.7rem;
}

.hero-role {
  font-size: 1.05rem;
  font-weight: 500;
  color: var(--accent-text);
  margin-bottom: 1.3rem;
}

.hero-bio {
  font-size: 1rem;
  line-height: 1.72;
  color: var(--text);
  margin-bottom: 1.6rem;
  max-width: 62ch;
}

.hero-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  list-style: none;
  margin-bottom: 1.8rem;
}

.hero-links a {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  font-size: 0.84rem;
  font-weight: 500;
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 0.38rem 0.8rem;
  border-radius: 999px;
  transition: border-color 0.15s ease, color 0.15s ease, transform 0.2s var(--ease);
}

.hero-links a:hover {
  color: var(--text-bright);
  border-color: var(--border-focus);
  transform: translateY(-1px);
}

.hero-links svg,
.icon {
  width: 15px;
  height: 15px;
  flex-shrink: 0;
  fill: none;
  stroke: var(--accent);
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.hero-actions {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.hero-photo {
  position: relative;
  justify-self: end;
  width: 100%;
  max-width: 260px;
}

.hero-photo picture {
  display: block;
}

.hero-photo img {
  width: 100%;
  height: auto;
  aspect-ratio: 4 / 5;
  object-fit: cover;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-md);
  background: var(--surface);
}

.hero-photo figcaption {
  margin-top: 0.7rem;
  font-size: 0.78rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  line-height: 1.25;
  padding: 0.65rem 1.15rem;
  font-size: 0.88rem;
  font-weight: 600;
  font-family: var(--font-sans);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background-color 0.15s ease, border-color 0.15s ease, color 0.15s ease, transform 0.2s var(--ease);
  white-space: nowrap;
}

.btn:active {
  transform: translateY(1px);
}

.btn-primary {
  background: var(--accent);
  color: var(--accent-contrast);
  border: 1px solid var(--accent);
}

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

.btn-outline {
  background: transparent;
  color: var(--text-bright);
  border: 1px solid var(--border);
}

.btn-outline:hover {
  background: var(--surface-raised);
  border-color: var(--border-focus);
  color: var(--text-bright);
}

.btn-sm {
  padding: 0.42rem 0.8rem;
  font-size: 0.8rem;
}

.arrow {
  display: inline-block;
  transition: transform 0.2s var(--ease);
}

a:hover > .arrow {
  transform: translateX(3px);
}

a:hover > .arrow-ne {
  transform: translate(2px, -2px);
}

/* Interests */
.interests-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1.25rem;
}

.interest-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.8rem 1.6rem;
  transition: border-color 0.2s ease, transform 0.25s var(--ease), box-shadow 0.25s ease;
}

.interest-card:hover {
  border-color: var(--border-focus);
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.interest-num {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--accent-text);
  display: inline-block;
  margin-bottom: 1.1rem;
  padding: 0.15rem 0.5rem;
  border: 1px solid var(--accent-badge-border);
  border-radius: var(--radius-sm);
  background: var(--accent-light);
}

.interest-title {
  font-size: 1.12rem;
  font-weight: 600;
  line-height: 1.35;
  margin-bottom: 0.6rem;
}

.interest-desc {
  font-size: 0.9rem;
  line-height: 1.65;
}

/* Projects split layout */
.works-split {
  display: grid;
  grid-template-columns: 270px minmax(0, 1fr);
  gap: 3.5rem;
}

.works-sidebar {
  position: sticky;
  top: 6rem;
  align-self: start;
  min-width: 0;
}

.works-sidebar .section-subtitle {
  margin-bottom: 1.4rem;
}

.works-count {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  margin-bottom: 1.4rem;
  padding-top: 1.2rem;
  border-top: 1px solid var(--border);
}

.works-count strong {
  font-size: 2.1rem;
  font-weight: 700;
  color: var(--text-bright);
  letter-spacing: -0.03em;
  line-height: 1;
}

.works-count span {
  font-size: 0.8rem;
  color: var(--text-muted);
  line-height: 1.4;
}

.works-list {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.work-item {
  padding: 2rem 0;
  border-top: 1px solid var(--border);
  min-width: 0;
}

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

.work-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin-bottom: 0.7rem;
}

.tag,
.work-tag {
  display: inline-block;
  font-size: 0.74rem;
  font-weight: 600;
  line-height: 1.5;
  color: var(--accent-text);
  background: var(--accent-light);
  border: 1px solid var(--accent-badge-border);
  padding: 0.1rem 0.55rem;
  border-radius: var(--radius-sm);
}

.work-period,
.project-card-period {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--text-muted);
  white-space: nowrap;
}

.work-title {
  font-size: 1.22rem;
  font-weight: 600;
  line-height: 1.35;
  margin-bottom: 0.5rem;
}

.work-title a {
  color: var(--text-bright);
  background-image: linear-gradient(var(--accent), var(--accent));
  background-size: 0% 1px;
  background-position: 0 100%;
  background-repeat: no-repeat;
  transition: background-size 0.3s var(--ease), color 0.15s ease;
}

.work-title a:hover {
  color: var(--text-bright);
  background-size: 100% 1px;
}

.work-desc {
  font-size: 0.93rem;
  line-height: 1.68;
  margin-bottom: 0.9rem;
}

.work-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 1.4rem;
  align-items: center;
}

.work-action-link {
  font-size: 0.86rem;
  font-weight: 600;
  color: var(--accent-text);
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

/* Equations */
.equation-container {
  position: relative;
  background: var(--inset-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1rem 1rem 0.8rem;
  margin: 0.7rem 0 1rem;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  max-width: 100%;
}

.equation-container.has-copy {
  padding-top: 2.1rem;
}

.equation-container .katex-display {
  margin: 0.25rem 0;
}

.copy-latex {
  position: absolute;
  top: 6px;
  right: 6px;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text-muted);
  font-family: var(--font-sans);
  font-size: 0.72rem;
  font-weight: 500;
  padding: 2px 8px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: color 0.15s ease, border-color 0.15s ease;
}

.copy-latex:hover {
  color: var(--text-bright);
  border-color: var(--border-focus);
}

/* Links inside running text are underlined so they don't rely on color alone */
.entry-bullets a,
.project-detail-card > p a,
.deepdive-section p a,
.deepdive-section li a {
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

/* Coursework */
.coursework-quad-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(230px, 100%), 1fr));
  gap: 1.25rem;
}

.course-panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.35rem;
  min-width: 0;
}

.course-panel-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.5rem;
  margin-bottom: 0.6rem;
  padding-bottom: 0.6rem;
  border-bottom: 1px solid var(--border);
}

.course-panel-header h3 {
  font-size: 0.95rem;
  font-weight: 600;
}

.course-panel-header .count {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-muted);
}

.course-entries {
  list-style: none;
  font-size: 0.88rem;
}

.course-entries li {
  padding: 0.42rem 0;
  border-bottom: 1px solid var(--border-soft);
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  line-height: 1.45;
}

.course-entries li:last-child {
  border-bottom: none;
}

.course-entries .code {
  font-family: var(--font-mono);
  color: var(--text-muted);
  font-size: 0.72rem;
  flex-shrink: 0;
  min-width: 6ch;
}

.section-foot {
  margin-top: 1.75rem;
}

/* Repositories */
.repo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(300px, 100%), 1fr));
  gap: 1.25rem;
}

.repo-card {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.35rem;
  display: flex;
  flex-direction: column;
  min-width: 0;
  transition: border-color 0.2s ease, transform 0.25s var(--ease), box-shadow 0.25s ease;
}

.repo-card:hover {
  border-color: var(--border-focus);
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.repo-card:focus-within {
  border-color: var(--border-focus);
}

.repo-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}

.repo-title {
  font-family: var(--font-mono);
  font-size: 0.92rem;
  font-weight: 600;
  min-width: 0;
  overflow-wrap: anywhere;
}

.repo-title a {
  color: var(--text-bright);
}

/* Whole card is clickable via the title link */
.repo-title a::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
}

.repo-title a:focus-visible {
  outline: none;
}

.repo-arrow {
  color: var(--text-muted);
  font-size: 0.85rem;
  transition: transform 0.2s var(--ease), color 0.15s ease;
}

.repo-card:hover .repo-arrow {
  color: var(--accent-text);
  transform: translate(2px, -2px);
}

.repo-desc {
  font-size: 0.87rem;
  line-height: 1.6;
  margin-bottom: 1.1rem;
  flex: 1;
}

.repo-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 1rem;
  font-size: 0.75rem;
  color: var(--text-muted);
  align-items: center;
  border-top: 1px solid var(--border-soft);
  padding-top: 0.7rem;
}

.lang-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

.lang-dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--accent);
}

.repo-updated {
  margin-left: auto;
  font-family: var(--font-mono);
}

/* Contact */
.contact-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 2.5rem;
}

.contact-info {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.6rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 1.2rem;
  min-width: 0;
}

.contact-address-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-bright);
  margin-bottom: 0.5rem;
}

.contact-address-text {
  font-style: normal;
  font-size: 0.93rem;
  line-height: 1.65;
}

.email-box {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--inset-bg);
  border: 1px solid var(--border);
  padding: 0.55rem 0.55rem 0.55rem 0.9rem;
  border-radius: var(--radius-md);
  margin-top: 1rem;
}

.email-box a {
  flex: 1;
  min-width: 0;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-bright);
  overflow-wrap: break-word;
}

.email-box a:hover {
  color: var(--accent-text);
}

.copy-btn {
  flex-shrink: 0;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text-muted);
  font-family: var(--font-sans);
  font-size: 0.74rem;
  font-weight: 600;
  padding: 0.3rem 0.65rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: color 0.15s ease, border-color 0.15s ease;
}

.copy-btn:hover {
  color: var(--text-bright);
  border-color: var(--border-focus);
}

.contact-footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 1.2rem;
  font-size: 0.84rem;
  border-top: 1px solid var(--border);
  padding-top: 0.9rem;
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.form-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 1rem;
}

.form-field {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  min-width: 0;
}

.form-field label {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.form-field input,
.form-field textarea {
  width: 100%;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text-bright);
  font-family: var(--font-sans);
  font-size: 1rem;
  padding: 0.65rem 0.85rem;
  border-radius: var(--radius-md);
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.form-field textarea {
  resize: vertical;
  min-height: 7.5rem;
}

.form-field input::placeholder,
.form-field textarea::placeholder {
  color: var(--text-muted);
  opacity: 0.75;
}

.form-field input:focus,
.form-field textarea:focus {
  outline: none;
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px var(--accent-light);
}

.form-note {
  font-size: 0.78rem;
  color: var(--text-muted);
  text-align: center;
}

.btn-block {
  width: 100%;
}

/* Inner pages */
.page-wrapper {
  padding-top: 3.5rem;
  padding-bottom: 4.5rem;
}

.page-header {
  margin-bottom: 2.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border);
}

.page-header-split {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  flex-wrap: wrap;
  gap: 1rem;
}

.page-header-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.page-title {
  font-size: clamp(1.7rem, 1.3rem + 1.4vw, 2.2rem);
  letter-spacing: -0.025em;
  line-height: 1.2;
  margin-bottom: 0.45rem;
}

.page-subtitle {
  font-size: 0.97rem;
  color: var(--text-muted);
  max-width: 65ch;
}

/* Project catalog */
.project-index {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  list-style: none;
  margin-bottom: 2rem;
}

.project-index a {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-muted);
  border: 1px solid var(--border);
  padding: 0.3rem 0.75rem;
  border-radius: 999px;
  transition: color 0.15s ease, border-color 0.15s ease;
}

.project-index a:hover {
  color: var(--text-bright);
  border-color: var(--border-focus);
}

.project-detail-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin-bottom: 1.5rem;
  min-width: 0;
  scroll-margin-top: 5.5rem;
  transition: border-color 0.3s ease, box-shadow 0.3s ease;
}

.project-detail-card:target {
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px var(--accent-light);
}

.project-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.75rem 1rem;
  margin-bottom: 0.9rem;
  flex-wrap: wrap;
}

.tech-tags {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  list-style: none;
}

.tech-tags li {
  font-size: 0.74rem;
  font-weight: 600;
  color: var(--accent-text);
  background: var(--accent-light);
  border: 1px solid var(--accent-badge-border);
  padding: 0.1rem 0.55rem;
  border-radius: var(--radius-sm);
}

.tech-tags.plain li {
  color: var(--text-muted);
  background: transparent;
  border-color: var(--border);
  font-weight: 500;
}

.project-detail-card h2 {
  font-size: 1.32rem;
  line-height: 1.3;
  letter-spacing: -0.01em;
  margin-bottom: 0.75rem;
}

.project-detail-card > p {
  max-width: 72ch;
}

.entry-bullets {
  margin: 1rem 0 0;
  padding-left: 1.2rem;
  max-width: 72ch;
}

.entry-bullets li {
  margin-bottom: 0.4rem;
  font-size: 0.93rem;
  line-height: 1.6;
}

.entry-bullets li::marker {
  color: var(--accent);
}

.project-card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 1.4rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
}

.project-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}

/* Writeup */
.deepdive-nav {
  margin-bottom: 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem 1rem;
  max-width: 800px;
  margin-inline: auto;
}

.link-back {
  font-size: 0.88rem;
  font-weight: 600;
  display: inline-flex;
  gap: 0.35rem;
}

.link-back:hover .arrow {
  transform: translateX(-3px);
}

.deepdive-context {
  font-size: 0.78rem;
  color: var(--text-muted);
}

.deepdive-article {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2.5rem 2.75rem;
  max-width: 800px;
  margin: 0 auto;
  min-width: 0;
}

.deepdive-header {
  padding-bottom: 1.5rem;
  margin-bottom: 2rem;
  border-bottom: 1px solid var(--border);
}

.deepdive-header .page-title {
  margin-bottom: 0.9rem;
}

.deepdive-meta {
  display: flex;
  gap: 0.4rem 1.5rem;
  flex-wrap: wrap;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.deepdive-meta dt {
  display: inline;
  font-weight: 600;
  color: var(--text);
}

.deepdive-meta dd {
  display: inline;
}

.deepdive-meta div {
  display: inline;
}

.deepdive-section {
  margin-bottom: 2.2rem;
}

.deepdive-section:last-child {
  margin-bottom: 0;
}

.deepdive-section h2 {
  font-size: 1.22rem;
  margin-bottom: 0.8rem;
  display: flex;
  gap: 0.6rem;
  align-items: baseline;
}

.deepdive-section h2 .sec-num {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--accent-text);
}

.deepdive-section p {
  margin-bottom: 1rem;
  max-width: 70ch;
}

.deepdive-section ul {
  padding-left: 1.3rem;
  margin-bottom: 1rem;
}

.deepdive-section li {
  margin-bottom: 0.5rem;
  line-height: 1.65;
}

.deepdive-section li::marker {
  color: var(--accent);
}

.callout-quote {
  background: var(--surface-raised);
  border: 1px solid var(--border);
  padding: 1.1rem 1.4rem;
  border-radius: var(--radius-md);
  margin: 1.2rem 0;
}

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

/* CV page */
.pdf-viewer-module {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin-bottom: 3.5rem;
}

.pdf-module-header {
  background: var(--surface-raised);
  padding: 0.6rem 1.2rem;
  border-bottom: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--text-muted);
}

.pdf-frame {
  width: 100%;
  height: 860px;
  border: none;
  display: block;
}

.pdf-fallback-box {
  padding: 3rem 1.5rem;
  text-align: center;
}

.pdf-fallback-box p {
  margin-bottom: 1rem;
  color: var(--text-muted);
}

.cv-section {
  margin-bottom: 3.5rem;
}

.cv-section:last-child {
  margin-bottom: 0;
}

.dual-feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(280px, 100%), 1fr));
  gap: 1.25rem;
}

.service-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
}

.service-card h3 {
  font-size: 1.08rem;
  font-weight: 600;
  margin-bottom: 0.2rem;
}

.service-card .service-meta {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--text-muted);
  margin-bottom: 0.7rem;
}

.service-card p {
  font-size: 0.92rem;
  line-height: 1.62;
}

/* 404 */
.notfound {
  padding-top: 6rem;
  padding-bottom: 6rem;
}

.notfound-code {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--accent-text);
  margin-bottom: 0.8rem;
}

.notfound .hero-actions {
  margin-top: 1.8rem;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border-soft);
  padding: 2.25rem 0;
  font-size: 0.86rem;
  color: var(--text-muted);
  background: var(--bg);
}

.footer-layout {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-meta {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}

.footer-meta small {
  font-size: 0.76rem;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.4rem;
  list-style: none;
}

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

.footer-links a:hover {
  color: var(--text-bright);
}

/* Responsive */
@media (max-width: 900px) {
  .hero-grid {
    grid-template-columns: minmax(0, 1fr) 200px;
    gap: 2.5rem;
  }

  .works-split {
    grid-template-columns: minmax(0, 1fr);
    gap: 2rem;
  }

  .works-sidebar {
    position: static;
  }

  .works-count {
    display: none;
  }

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

  .contact-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 2rem;
  }

  /* Inline PDF viewers are unreliable on touch devices; the header buttons remain */
  .pdf-viewer-module {
    display: none;
  }
}

@media (max-width: 760px) {
  .nav-container {
    flex-wrap: wrap;
    padding: 0.6rem 1rem 0.35rem;
    gap: 0.35rem 0.75rem;
  }

  .brand {
    flex: 1;
    font-size: 0.95rem;
  }

  .theme-toggle-btn {
    order: 2;
    width: 32px;
    height: 32px;
  }

  .site-nav {
    order: 3;
    width: 100%;
    margin-left: 0;
  }

  .nav-links {
    margin: 0 -0.65rem;
    width: calc(100% + 1.3rem);
    gap: 0;
    overflow-x: auto;
    scrollbar-width: none;
    -webkit-overflow-scrolling: touch;
    mask-image: linear-gradient(to right, #000 calc(100% - 24px), transparent);
    -webkit-mask-image: linear-gradient(to right, #000 calc(100% - 24px), transparent);
  }

  .nav-links::-webkit-scrollbar {
    display: none;
  }

  .nav-links li:last-child {
    padding-right: 1.2rem;
  }

  .nav-links a {
    font-size: 0.83rem;
    white-space: nowrap;
    padding: 0.35rem 0.65rem;
  }

  html {
    scroll-padding-top: 7rem;
  }

  .project-detail-card {
    scroll-margin-top: 7rem;
  }

  .hero-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 1.6rem;
  }

  .hero-photo {
    order: -1;
    justify-self: start;
    width: 112px;
  }

  .hero-photo img {
    aspect-ratio: 1 / 1;
    border-radius: 50%;
  }

  .hero-photo figcaption {
    display: none;
  }
}

@media (max-width: 420px) {
  /* The brand already links home; keeps every other nav item on screen */
  .nav-links li:first-child {
    display: none;
  }

  .nav-links a {
    padding: 0.35rem 0.55rem;
  }

  .equation-container {
    padding-left: 0.75rem;
    padding-right: 0.75rem;
  }

  .equation-container .katex-display > .katex {
    font-size: 0.9em;
  }
}

@media (max-width: 600px) {
  .container {
    padding: 0 1rem;
  }

  .section {
    padding: 3rem 0;
  }

  .section-head {
    margin-bottom: 1.6rem;
  }

  .section-headline {
    font-size: 1.5rem;
  }

  .section-subtitle {
    font-size: 0.9rem;
  }

  .hero-section {
    padding: 2.25rem 0 2.75rem;
  }

  .hero-role {
    font-size: 0.95rem;
    margin-bottom: 1rem;
  }

  .hero-bio {
    font-size: 0.94rem;
    line-height: 1.66;
  }

  .hero-links {
    margin-bottom: 1.4rem;
  }

  .hero-actions {
    flex-direction: column;
  }

  .hero-actions .btn {
    width: 100%;
  }

  .interest-card {
    padding: 1.35rem;
  }

  .work-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.4rem;
  }

  .work-title {
    font-size: 1.1rem;
  }

  .equation-container {
    font-size: 0.88rem;
  }

  .course-panel {
    padding: 1.15rem;
  }

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

  .contact-info {
    padding: 1.25rem;
  }

  .page-wrapper {
    padding-top: 2rem;
    padding-bottom: 3rem;
  }

  .project-detail-card {
    padding: 1.3rem;
  }

  .project-detail-card h2 {
    font-size: 1.15rem;
  }

  .project-card-footer {
    flex-direction: column;
    align-items: stretch;
  }

  .project-actions {
    flex-direction: column;
  }

  .project-actions .btn,
  .page-header-actions .btn {
    width: 100%;
  }

  .page-header-actions {
    width: 100%;
    flex-direction: column;
  }

  .deepdive-article {
    padding: 1.4rem 1.2rem;
  }

  .deepdive-meta {
    flex-direction: column;
  }

  .callout-quote {
    padding: 0.9rem 1rem;
  }

  .site-footer {
    padding: 1.75rem 0;
  }

  .footer-layout {
    flex-direction: column;
    align-items: flex-start;
  }

  .footer-links {
    gap: 0.5rem 1.1rem;
  }
}

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

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

  .interest-card:hover,
  .repo-card:hover,
  .hero-links a:hover {
    transform: none;
  }
}

@media print {
  .site-header,
  .site-footer,
  .theme-toggle-btn,
  .copy-latex,
  .contact-form,
  .skip-link {
    display: none !important;
  }

  body {
    background: #fff;
    color: #000;
  }
}