/* ----------------------------------------------------------------------------
   Base styles for the site. Plain CSS, no preprocessor.
   Design tokens live in :root; tweak those first to re-skin the site.
---------------------------------------------------------------------------- */

/* ----------------------------------------------------------------------------
   Color scheme: follows the OS/browser preference.
     - OS set to dark   -> dark
     - OS set to light  -> light
     - OS unset/unknown -> light

   Note on the "unset" case: browsers do not expose a separate "no preference"
   signal; a user who hasn't chosen reports as light (prefers-color-scheme:
   no-preference was removed from the spec and never matches). So light is the
   base, and an explicit dark preference overrides it. Pure CSS, no JS.

   `color-scheme: light dark` themes native form controls, scrollbars, and the
   canvas to match, and Safari/WebKit requires it to render dark controls.
---------------------------------------------------------------------------- */

:root {
  /* Palettes, each value defined once. */
  --light-bg: #ffffff;
  --light-surface: #f6f7f9;
  --light-text: #1a1d21;
  --light-muted: #5b636c;
  --light-accent: #2f6df0;
  --light-accent-strong: #1f4fc2;
  --light-border: #e4e7eb;

  --dark-bg: #0f1115;
  --dark-surface: #181b22;
  --dark-text: #e7e9ee;
  --dark-muted: #9aa3af;
  --dark-accent: #5b8cff;
  --dark-accent-strong: #7aa2ff;
  --dark-border: #2a2f37;

  /* Active theme: light base (also covers the unset case). */
  --color-bg: var(--light-bg);
  --color-surface: var(--light-surface);
  --color-text: var(--light-text);
  --color-muted: var(--light-muted);
  --color-accent: var(--light-accent);
  --color-accent-dark: var(--light-accent-strong);
  --color-border: var(--light-border);

  color-scheme: light dark;

  --font-sans: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial,
    sans-serif;

  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 2rem;
  --space-lg: 4rem;

  --maxw: 64rem;
  --radius: 0.625rem;
}

/* Explicit dark preference. */
@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: var(--dark-bg);
    --color-surface: var(--dark-surface);
    --color-text: var(--dark-text);
    --color-muted: var(--dark-muted);
    --color-accent: var(--dark-accent);
    --color-accent-dark: var(--dark-accent-strong);
    --color-border: var(--dark-border);
  }
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

a:hover {
  text-decoration: underline;
}

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

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

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--color-bg); /* fallback where color-mix is unsupported */
  background: color-mix(in srgb, var(--color-bg) 88%, transparent);
  -webkit-backdrop-filter: blur(8px); /* Safari */
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 3.75rem;
}

.brand {
  font-weight: 700;
  font-size: 1.125rem;
  color: var(--color-text);
}

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

.nav {
  display: flex;
  gap: var(--space-sm);
}

.nav a {
  color: var(--color-muted);
  font-weight: 500;
  padding: var(--space-xs) 0;
}

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

.nav a[aria-current="page"] {
  color: var(--color-text);
  border-bottom: 2px solid var(--color-accent);
}

/* Hamburger button: hidden on desktop, shown under the breakpoint. */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 2.5rem;
  height: 2.5rem;
  padding: 0;
  background: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  cursor: pointer;
}

.nav-toggle-bar {
  display: block;
  width: 1.25rem;
  height: 2px;
  margin-inline: auto;
  background: var(--color-text);
  transition: transform 0.2s ease, opacity 0.2s ease;
}

/* ---- Layout primitives -------------------------------------------------- */

main {
  min-height: 60vh;
}

.section {
  padding-block: var(--space-lg);
}

.hero {
  padding-block: var(--space-lg);
  text-align: center;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3.25rem);
  line-height: 1.1;
  margin: 0 0 var(--space-sm);
}

.hero p {
  font-size: 1.125rem;
  color: var(--color-muted);
  max-width: 36rem;
  margin: 0 auto var(--space-md);
}

.button {
  display: inline-block;
  background: var(--color-accent);
  color: #fff;
  font-weight: 600;
  padding: 0.7rem 1.4rem;
  border-radius: var(--radius);
  transition: background 0.15s ease;
}

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

.button.secondary {
  background: transparent;
  color: var(--color-accent);
  border: 1px solid var(--color-border);
}

.button.secondary:hover {
  background: var(--color-surface);
}

.button-row {
  display: flex;
  gap: var(--space-sm);
  justify-content: center;
  flex-wrap: wrap;
}

.page-title {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  margin: 0 0 var(--space-xs);
}

.lead {
  color: var(--color-muted);
  font-size: 1.125rem;
  margin-top: 0;
}

/* ---- Article list ------------------------------------------------------- */

.article-list {
  list-style: none;
  padding: 0;
  margin: var(--space-md) 0 0;
  display: grid;
  gap: var(--space-sm);
}

.article-card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: var(--space-sm) var(--space-md);
  transition: border-color 0.15s ease, transform 0.15s ease;
}

.article-card:hover {
  border-color: var(--color-accent);
  transform: translateY(-2px);
}

.article-card h2 {
  margin: 0 0 0.25rem;
  font-size: 1.25rem;
}

.article-card h2 a {
  color: var(--color-text);
}

.article-card time {
  color: var(--color-muted);
  font-size: 0.875rem;
}

.article-card p {
  margin: 0.5rem 0 0;
  color: var(--color-muted);
}

/* ---- Article body ------------------------------------------------------- */

.prose {
  max-width: 42rem;
}

.prose h1 {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  margin-bottom: var(--space-xs);
}

.prose .meta {
  color: var(--color-muted);
  font-size: 0.9rem;
  margin-bottom: var(--space-md);
}

.prose p {
  margin: 0 0 var(--space-sm);
}

/* ---- Contact ------------------------------------------------------------ */

.contact-grid {
  display: grid;
  gap: var(--space-sm);
  margin-top: var(--space-md);
}

.contact-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: var(--space-sm) var(--space-md);
}

.contact-item h2 {
  margin: 0 0 0.25rem;
  font-size: 1rem;
}

.contact-item p {
  margin: 0;
  color: var(--color-muted);
}

/* ---- Resume ------------------------------------------------------------- */

.download-row {
  margin-top: var(--space-md);
}

.resume-embed {
  display: block;
  width: 100%;
  height: 80vh;
  min-height: 32rem;
  margin-top: var(--space-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}

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

.site-footer {
  border-top: 1px solid var(--color-border);
  margin-top: var(--space-lg);
  padding-block: var(--space-md);
  color: var(--color-muted);
  font-size: 0.9rem;
  text-align: center;
}

/* ---- Mobile nav --------------------------------------------------------- */

@media (max-width: 40rem) {
  .nav-toggle {
    display: flex;
  }

  .brand {
    font-size: 1rem;
  }

  .nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-xs) var(--space-sm);

    /* Animated open/close, driven by the .is-open class toggled in main.ts */
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    transition: max-height 0.25s ease, opacity 0.25s ease;
  }

  .nav.is-open {
    max-height: 16rem;
    opacity: 1;
  }

  .nav a {
    padding: var(--space-xs) 0;
  }
}