/* ==========================================================================
   1. CSS custom properties / design tokens
   ========================================================================== */

:root {
  /* Colors — OKLCH palette */
  --color-bg: oklch(0.992 0.008 235);
  --color-surface-warm: oklch(0.975 0.014 82);
  --color-surface-footer: oklch(0.30 0.045 245);
  --color-text: oklch(0.28 0.04 250);
  --color-text-secondary: oklch(0.48 0.03 250);
  --color-text-muted: oklch(0.58 0.025 250);
  --color-text-footer: oklch(0.94 0.015 90);
  --color-accent: oklch(0.56 0.11 230);
  --color-accent-strong: oklch(0.46 0.13 230);
  --color-accent-subtle: oklch(0.93 0.04 230);
  --color-accent-line: oklch(0.87 0.035 235);
  --color-border: oklch(0.88 0.02 240);
  --color-border-subtle: oklch(0.92 0.018 245);
  --color-focus: oklch(0.42 0.14 230);
  --color-skip-bg: oklch(0.24 0.05 250);
  --color-skip-text: oklch(0.97 0.01 90);
  --color-skip-border: oklch(0.42 0.04 245);

  --color-heading: oklch(0.27 0.055 248);

  /* Typography */
  --font-sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --text-base: clamp(1rem, 0.96rem + 0.2vw, 1.0625rem);
  --text-sm: clamp(0.875rem, 0.85rem + 0.15vw, 0.9375rem);
  --text-lg: clamp(1.125rem, 1.05rem + 0.35vw, 1.25rem);
  --text-brand: clamp(1.25rem, 1.1rem + 0.5vw, 1.5rem);
  --text-h2: clamp(1.5rem, 1.3rem + 0.8vw, 2rem);
  --text-h3: clamp(1.125rem, 1.05rem + 0.4vw, 1.375rem);
  --text-hero: clamp(2.25rem, 1.6rem + 2.8vw, 3.75rem);
  --line-height-body: 1.65;
  --line-height-heading: 1.25;
  --line-height-hero: 1.15;

  /* Spacing */
  --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: 4rem;
  --space-9: clamp(4rem, 3rem + 4vw, 6rem);
  --space-10: clamp(5rem, 3.5rem + 5vw, 7rem);

  /* Layout */
  --content-max: 72rem;
  --reading-max: 65ch;
  --gutter: clamp(1.25rem, 0.75rem + 2vw, 2rem);
  --touch-min: 2.75rem;
}


/* ==========================================================================
   2. Reset / sensible defaults
   ========================================================================== */

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

* {
  margin: 0;
}

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

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


/* ==========================================================================
   3. Base typography and body styles
   ========================================================================== */

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-body);
  color: var(--color-text);
  background-color: var(--color-bg);
  min-height: 100vh;
  overflow-x: hidden;
}

h1,
h2,
h3,
h4 {
  line-height: var(--line-height-heading);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text);
}

h1 {
  font-size: var(--text-hero);
  line-height: var(--line-height-hero);
  letter-spacing: -0.02em;
}

h2 {
  font-size: var(--text-h2);
  letter-spacing: -0.01em;
}

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

h4 {
  font-size: var(--text-base);
  font-weight: var(--font-weight-semibold);
}

p {
  max-width: var(--reading-max);
}

p + p {
  margin-block-start: var(--space-4);
}

ul {
  list-style: none;
  padding: 0;
}

main {
  max-width: var(--content-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}


/* ==========================================================================
   4. Global links and focus styles
   ========================================================================== */

a {
  color: var(--color-accent-strong);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.15em;
}

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

:focus {
  outline: none;
}

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

a:focus-visible {
  border-radius: 2px;
}


/* ==========================================================================
   5. Skip link
   ========================================================================== */

body > a[href="#main-content"] {
  position: fixed;
  inset-inline-start: var(--gutter);
  inset-block-start: var(--space-2);
  z-index: 100;
  padding: var(--space-1) var(--space-2);
  font-size: 0.8125rem;
  line-height: 1.3;
  background-color: var(--color-skip-bg);
  color: var(--color-skip-text);
  font-weight: var(--font-weight-medium);
  text-decoration: none;
  border: 1px solid var(--color-skip-border);
  border-radius: 3px;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  overflow: hidden;
  white-space: nowrap;
}

body > a[href="#main-content"]:focus {
  clip: auto;
  clip-path: none;
  overflow: visible;
}


/* ==========================================================================
   6. Header and navigation
   ========================================================================== */

header {
  max-width: var(--content-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
  padding-block: var(--space-5);
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: var(--space-4);
}

header > a {
  display: inline-flex;
  align-items: center;
  color: var(--color-text);
  font-size: var(--text-brand);
  font-weight: 700;
  line-height: 1;
  text-decoration: none;
}

header > a:hover {
  color: var(--color-accent-strong);
  text-decoration: none;
}

nav {
  display: flex;
  align-items: center;
}

nav ul {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2) var(--space-4);
  max-inline-size: 100%;
}

nav a {
  display: inline-flex;
  align-items: center;
  min-block-size: var(--touch-min);
  padding-inline: var(--space-1);
  color: var(--color-text-secondary);
  font-weight: var(--font-weight-medium);
  text-decoration: none;
}

nav a:hover {
  color: var(--color-accent-strong);
  text-decoration: underline;
}

.menu-toggle {
  display: none;
}

html.js .menu-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-block-size: var(--touch-min);
  padding-inline: var(--space-3);
  padding-block: var(--space-2);
  font-family: inherit;
  font-size: var(--text-base);
  font-weight: var(--font-weight-medium);
  line-height: 1;
  color: var(--color-text-secondary);
  background: none;
  border: 1px solid var(--color-border-subtle);
  border-radius: 4px;
  cursor: pointer;
}

html.js .menu-toggle:hover {
  color: var(--color-accent-strong);
  border-color: var(--color-accent-line);
}

html.js header {
  flex-direction: row;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
}

html.js #primary-navigation {
  flex-basis: 100%;
}

html.js #primary-navigation[hidden] {
  display: none;
}

html.js #primary-navigation ul {
  flex-direction: column;
  gap: var(--space-1);
  width: 100%;
}

/* Selected nav state when a section is targeted */
body:has(#about:target) nav a[href="#about"],
body:has(#skills:target) nav a[href="#skills"],
body:has(#projects:target) nav a[href="#projects"],
body:has(#education:target) nav a[href="#education"],
body:has(#contact:target) nav a[href="#contact"] {
  color: var(--color-accent-strong);
  text-decoration: underline;
  text-decoration-thickness: 2px;
}


/* ==========================================================================
   7. Hero
   ========================================================================== */

#hero {
  padding-block: var(--space-10) var(--space-9);
}

#hero h1 {
  max-width: 18ch;
  padding-block-end: var(--space-4);
}

#hero h1::after {
  content: "";
  display: block;
  inline-size: 3rem;
  block-size: 3px;
  margin-block-start: var(--space-4);
  background-color: var(--color-accent);
  border-radius: 2px;
}

#hero p:first-of-type {
  margin-block-start: var(--space-5);
  font-size: var(--text-lg);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
  max-width: var(--reading-max);
}

#hero p:last-of-type {
  margin-block-start: var(--space-6);
  color: var(--color-text);
}


/* ==========================================================================
   8. Shared section styles
   ========================================================================== */

main > section {
  padding-block: var(--space-8);
  border-block-start: 1px solid var(--color-border-subtle);
}

main > section:first-of-type {
  border-block-start: none;
}

main > section > h2 {
  margin-block-end: var(--space-6);
  color: var(--color-heading);
}


/* ==========================================================================
   9. Skills
   ========================================================================== */

#skills {
  display: grid;
  gap: var(--space-5);
}

#skills > h2 {
  grid-column: 1 / -1;
}

#skills > section {
  padding-block: var(--space-3);
  padding-inline-start: var(--space-4);
  border-inline-start: 2px solid var(--color-border);
  border-block-start: 1px solid var(--color-border-subtle);
}

#skills > section:first-of-type {
  border-block-start: none;
  padding-block-start: 0;
}

#skills > section > h3 {
  margin-block-end: var(--space-2);
  font-size: var(--text-sm);
  font-weight: var(--font-weight-semibold);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--color-accent-strong);
}

#skills ul {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-1);
  line-height: 1.5;
}

#skills li {
  color: var(--color-text-secondary);
  font-size: var(--text-sm);
}

#skills li:not(:last-child)::after {
  content: " ·";
  color: var(--color-accent);
  font-weight: var(--font-weight-normal);
}


/* ==========================================================================
   10. Projects
   ========================================================================== */

#projects article {
  padding-block: var(--space-7);
  border-block-start: 1px solid var(--color-border-subtle);
}

#projects article:first-of-type {
  padding-block-start: 0;
  border-block-start: none;
}

#projects article:last-of-type {
  padding-block-end: 0;
}

#projects article h3 {
  margin-block-end: var(--space-2);
  color: var(--color-text);
}

#projects article h3 + p {
  font-size: var(--text-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
  margin-block-end: var(--space-4);
}

#projects article p {
  color: var(--color-text);
}

#projects article h4 {
  margin-block-start: var(--space-5);
  margin-block-end: var(--space-3);
  color: var(--color-text);
}

#projects article h4 ~ p {
  color: var(--color-text-secondary);
}

#projects article h4 ~ a {
  display: inline-flex;
  align-items: center;
  padding-inline: var(--space-1);
  color: var(--color-accent-strong);
  font-weight: var(--font-weight-medium);
  text-decoration: none;
}

#projects article h4 ~ a:hover {
  color: var(--color-accent-strong);
  text-decoration: underline;
}




/* ==========================================================================
   11. Education
   ========================================================================== */

#education article {
  padding-block: var(--space-4);
}

#education article:first-of-type {
  padding-block-start: 0;
}

#education article:last-of-type {
  padding-block-end: 0;
}

#education article + article {
  border-block-start: 1px solid var(--color-border-subtle);
  margin-block-start: var(--space-2);
}

#education article h3 {
  margin-block-end: var(--space-4);
  font-size: var(--text-base);
  font-weight: var(--font-weight-semibold);
}

#education dl {
  display: grid;
  grid-template-columns: minmax(6rem, auto) 1fr;
  gap: var(--space-2) var(--space-5);
  max-width: var(--reading-max);
}

#education dt {
  font-size: var(--text-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-muted);
}

#education dd {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin: 0;
}


/* ==========================================================================
   12. Contact
   ========================================================================== */

#contact ul {
  display: flex;
  flex-direction: row;
  gap: var(--space-3);
  max-width: var(--reading-max);
  padding-inline-start: var(--space-4);
  border-inline-start: 2px solid var(--color-accent-line);
}

#contact a {
  display: inline-flex;
  align-items: center;
  min-block-size: var(--touch-min);
  padding-block: var(--space-2);
  padding-inline: var(--space-1);
  color: var(--color-accent-strong);
  font-weight: var(--font-weight-medium);
  text-decoration: none;
}

#contact a:hover {
  color: var(--color-accent-strong);
  text-decoration: underline;
}

#contact li:not(:last-child)::after {
    content: " ·";
    color: var(--color-accent);
    font-weight: var(--font-weight-normal);
}

@media (max-width: 39.999rem) {
  #contact ul {
    gap: var(--space-2);
  }

  #contact a {
    padding-block: var(--space-1);
  }
}


/* ==========================================================================
   13. Footer
   ========================================================================== */

footer {
  background-color: var(--color-surface-footer);
  padding-block: var(--space-5);
  padding-inline: var(--gutter);
}

footer p {
  max-width: var(--content-max);
  margin-inline: auto;
  font-size: var(--text-sm);
  color: var(--color-text-footer);
  text-align: center;
}


/* ==========================================================================
   14. Responsive media queries
   ========================================================================== */

/* Tablet — horizontal header, two-column skills */
@media (min-width: 40rem) {
  header {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    padding-block: var(--space-6);
  }

  html.js .menu-toggle {
    display: none;
  }

  html.js header {
    flex-wrap: nowrap;
  }

  html.js #primary-navigation {
    flex-basis: auto;
  }

  html.js #primary-navigation ul {
    flex-direction: row;
    flex-wrap: wrap;
    gap: var(--space-2) var(--space-4);
    width: auto;
  }

  header > a {
    min-block-size: var(--touch-min);
  }

  nav ul {
    align-items: center;
  }

  #skills {
    grid-template-columns: repeat(2, 1fr);
    column-gap: var(--space-7);
    row-gap: var(--space-6);
  }

  #skills > section:nth-of-type(-n + 2) {
    border-block-start: none;
    padding-block-start: 0;
  }

  #skills > section:nth-of-type(n + 3) {
    border-block-start: 1px solid var(--color-border-subtle);
    padding-block-start: var(--space-5);
  }

  #contact ul {
    flex-direction: row;
    flex-wrap: wrap;
    align-items: center;
    gap: var(--space-1);
  }
}

/* Desktop — generous spacing, optional four-column skills */
@media (min-width: 64rem) {
  #hero {
    padding-block: var(--space-10) var(--space-9);
  }

  main > section {
    padding-block: var(--space-9);
  }

  #projects article {
    padding-block: var(--space-8);
  }
}