/* ===== Design Tokens ===== */
:root {
  --color-bg: #e6e6e6;
  --color-surface: #fff;
  --color-text: #333;
  --color-text-light: #555;
  --color-link: #2a6496;
  --color-link-hover: #1a4a6e;
  --color-nav-bg: #222;
  --color-nav-text: #9d9d9d;
  --color-nav-text-hover: #fff;
  --color-footer-bg: #111;
  --color-footer-text: #ccc;
  --color-overlay-light: rgba(250, 250, 255, 0.92);
  --color-overlay-dark: rgba(51, 51, 51, 0.75);
  --color-overlay-mid: rgba(150, 148, 154, 0.5);
  --max-width: 960px;
  --nav-height: 3.25rem;
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 2rem;
  --spacing-lg: 4rem;
  --spacing-xl: 6rem;
  --radius: 4px;
}

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

body, h1, h2, h3, h4, h5, h6, p, ul, ol, figure {
  margin: 0;
  padding: 0;
}

img { max-width: 100%; height: auto; display: block; }
ul { list-style: none; }
a { color: var(--color-link); text-decoration: none; }
a:hover { color: var(--color-link-hover); text-decoration: underline; }

/* ===== Base ===== */
html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

main {
  flex: 1;
  width: 100%;
}

h1 { font-size: 2rem; line-height: 1.2; }
h2 { font-size: 1.5rem; line-height: 1.3; margin-top: var(--spacing-md); }
h3 { font-size: 1.25rem; line-height: 1.3; margin-top: var(--spacing-sm); }
h4, h5, h6 { font-size: 1rem; line-height: 1.4; }

p { margin-top: var(--spacing-sm); }
ul { list-style: disc; padding-left: 1.5em; }
code { background: #f4f4f4; padding: 0.15em 0.4em; border-radius: var(--radius); font-size: 0.9em; }
pre code { display: block; padding: var(--spacing-sm); overflow-x: auto; }

.container {
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: var(--spacing-sm);
}

/* ===== Skip Link ===== */
.skip-link {
  position: absolute;
  top: -100%;
  left: var(--spacing-sm);
  background: var(--color-nav-bg);
  color: var(--color-nav-text-hover);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius);
  z-index: 1000;
}
.skip-link:focus {
  top: var(--spacing-xs);
  text-decoration: none;
  color: var(--color-nav-text-hover);
}

/* ===== Navigation ===== */
.site-nav {
  background: var(--color-nav-bg);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  padding: 0 var(--spacing-sm);
  position: sticky;
  top: 0;
  z-index: 100;
}

.site-nav__brand {
  color: var(--color-nav-text-hover);
  font-weight: 700;
  font-size: 1.125rem;
  padding: var(--spacing-xs) 0;
  text-decoration: none;
  margin-right: auto;
}
.site-nav__brand:hover {
  color: var(--color-nav-text-hover);
  text-decoration: none;
}

/* Hamburger toggle — hidden checkbox drives mobile menu */
.site-nav__toggle {
  display: none;
}

.site-nav__hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  cursor: pointer;
  padding: var(--spacing-xs);
}
.site-nav__hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-nav-text);
  border-radius: 1px;
  transition: transform 0.2s, opacity 0.2s;
}

.site-nav__menu {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.site-nav__menu a {
  color: var(--color-nav-text);
  padding: var(--spacing-xs) var(--spacing-sm);
  display: block;
  text-decoration: none;
  white-space: nowrap;
}
.site-nav__menu a:hover,
.site-nav__menu a:focus {
  color: var(--color-nav-text-hover);
  text-decoration: none;
}
.site-nav__menu a[aria-current="page"] {
  color: var(--color-nav-text-hover);
}

/* Dropdown */
.site-nav__dropdown {
  position: relative;
}
.site-nav__dropdown-trigger {
  cursor: pointer;
}
.site-nav__dropdown-trigger::after {
  content: " \25BE"; /* small down triangle */
  font-size: 0.75em;
}
.site-nav__dropdown-menu {
  display: none;
  position: absolute;
  top: 100%;
  right: 0;
  background: var(--color-nav-bg);
  min-width: 200px;
  padding: var(--spacing-xs) 0;
  border-radius: var(--radius);
  box-shadow: 0 4px 12px rgba(0,0,0,0.3);
}
.site-nav__dropdown-menu a {
  padding: var(--spacing-xs) var(--spacing-sm);
}
.site-nav__dropdown:hover .site-nav__dropdown-menu,
.site-nav__dropdown:focus-within .site-nav__dropdown-menu {
  display: block;
}

/* Mobile nav */
@media (max-width: 768px) {
  .site-nav__hamburger {
    display: flex;
  }
  .site-nav__menu {
    display: none;
    flex-direction: column;
    width: 100%;
    padding-bottom: var(--spacing-xs);
  }
  .site-nav__menu a {
    padding: var(--spacing-xs) 0;
  }
  .site-nav__toggle:checked ~ .site-nav__menu {
    display: flex;
  }
  /* Animate hamburger to X */
  .site-nav__toggle:checked ~ .site-nav__hamburger span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }
  .site-nav__toggle:checked ~ .site-nav__hamburger span:nth-child(2) {
    opacity: 0;
  }
  .site-nav__toggle:checked ~ .site-nav__hamburger span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }
  /* Dropdown on mobile: show inline */
  .site-nav__dropdown-menu {
    position: static;
    box-shadow: none;
    padding-left: var(--spacing-sm);
  }
}

/* ===== Footer ===== */
.site-footer {
  background: var(--color-footer-bg);
  color: var(--color-footer-text);
  padding: var(--spacing-md) var(--spacing-sm);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-lg);
}

.site-footer a {
  color: var(--color-footer-text);
  margin-left: var(--spacing-sm);
}
.site-footer a:hover {
  color: var(--color-nav-text-hover);
}

/* ===== Page: Project detail (shared) ===== */
.page-header {
  text-align: center;
  padding: var(--spacing-lg) var(--spacing-sm) var(--spacing-md);
}
.page-header h1 { margin-bottom: var(--spacing-xs); }
.page-header p { color: var(--color-text-light); }

.content-section {
  padding-bottom: var(--spacing-md);
}

/* ===== Page: Home ===== */
.hero {
  text-align: center;
  padding: var(--spacing-xl) var(--spacing-sm);
  background: var(--color-nav-bg);
  color: var(--color-nav-text-hover);
}
.hero h1 { font-size: 2.5rem; margin-bottom: var(--spacing-xs); }
.hero p { color: var(--color-nav-text); font-size: 1.125rem; }

.project-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: var(--spacing-md);
  padding: var(--spacing-md) 0;
}

.project-card {
  background: var(--color-surface);
  border-radius: var(--radius);
  overflow: hidden;
  transition: box-shadow 0.2s;
}
.project-card:hover {
  box-shadow: 0 4px 16px rgba(0,0,0,0.12);
}
.project-card img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
}
.project-card__body {
  padding: var(--spacing-sm);
}
.project-card__body h3 { font-size: 1.125rem; }
.project-card__body h3 a { color: var(--color-text); }
.project-card__body h3 a:hover { color: var(--color-link); text-decoration: none; }
.project-card__body p {
  font-size: 0.875rem;
  color: var(--color-text-light);
}

/* ===== Page: Resume ===== */
.resume-header {
  text-align: center;
  padding: var(--spacing-lg) var(--spacing-sm) var(--spacing-sm);
}
.resume-header h1 { margin-bottom: var(--spacing-xs); }
.resume-contact { color: var(--color-text-light); }

.resume-section {
  padding: var(--spacing-md) 0;
  border-top: 1px solid #ccc;
}
.resume-section h2 {
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-light);
  margin: 0 0 var(--spacing-sm);
}

.resume-entry { margin-bottom: var(--spacing-md); }
.resume-entry:last-child { margin-bottom: 0; }

.resume-entry-header {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  align-items: baseline;
}
.resume-entry-header h3 { font-size: 1rem; margin: 0; }
.resume-location { font-weight: normal; color: var(--color-text-light); font-size: 0.875rem; }
.resume-dates {
  font-style: italic;
  color: var(--color-text-light);
  font-size: 0.875rem;
}
.resume-title {
  font-style: italic;
  margin-top: 0.25rem;
}
.resume-section ul { margin-top: var(--spacing-xs); }
.resume-section li { margin-bottom: var(--spacing-xs); }
.resume-section li ul { margin-top: var(--spacing-xs); }

@media (min-width: 768px) {
  .resume-section {
    display: grid;
    grid-template-columns: 160px 1fr;
    gap: var(--spacing-md);
  }
  .resume-section h2 {
    text-align: right;
    border-top: none;
    margin: 0;
  }
}

/* ===== Page: Arduino Projects hub ===== */
.arduino-hero-img {
  width: 100%;
  max-height: 400px;
  object-fit: cover;
}

.arduino-overlay {
  background: var(--color-overlay-light);
  padding: var(--spacing-md) var(--spacing-sm);
}

.arduino-project-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--spacing-md);
  text-align: center;
  padding: var(--spacing-md) 0;
  max-width: var(--max-width);
  margin-inline: auto;
}

.arduino-project-card {
  position: relative;
  display: block;
}
.arduino-project-card img {
  border-radius: var(--radius);
  margin-inline: auto;
  max-width: 80%;
}
.arduino-project-card::after {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--color-overlay-mid);
  border-radius: var(--radius);
  opacity: 1;
  transition: opacity 0.2s;
  pointer-events: none;
}
.arduino-project-card:hover::after {
  opacity: 0;
}

/* ===== Page: Project with side media ===== */
.media-text {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-md);
  align-items: flex-start;
}
.media-text > * { flex: 1 1 300px; }
.media-text img { border-radius: var(--radius); }

.side-image-right {
  float: right;
  max-width: 35%;
  margin: 0 0 var(--spacing-sm) var(--spacing-sm);
  border-radius: var(--radius);
}

/* ===== Page: Graphing Application ===== */
.interactive-screenshot {
  position: relative;
  text-align: center;
  padding-bottom: var(--spacing-xl);
  margin-bottom: 15%;
}
.interactive-screenshot img {
  position: relative;
  max-width: 85%;
  height: auto;
  margin-inline: auto;
}
.interactive-screenshot .overlay-box {
  background: rgba(0,0,0,0);
  transition: background 0.2s;
}
.interactive-screenshot .overlay-box:hover {
  background: var(--color-overlay-dark);
}
.overlay-description {
  font-size: 0.875rem;
  position: relative;
  top: 35%;
  margin-inline: 10%;
  color: #fff;
  visibility: hidden;
}
.overlay-box:hover .overlay-description {
  visibility: visible;
}
.overlay-row {
  background: rgba(0,0,0,0) !important;
}
.overlay-row:hover {
  background: rgba(0,0,0,0) !important;
}
.overlay-row > div:hover .overlay-description {
  visibility: visible;
}

/* ===== Page: Dead embed placeholder ===== */
.embed-placeholder {
  background: #ddd;
  border-radius: var(--radius);
  padding: var(--spacing-lg);
  text-align: center;
  color: var(--color-text-light);
  font-style: italic;
}

/* ===== Utilities ===== */
.text-center { text-align: center; }
.text-bold { font-weight: 600; }