/* =========================================================
   Dave Knight — personal site
   Theming knobs live in :root. Re-skin here later.
   ========================================================= */

:root {
  /* Color */
  --color-bg: #f4f3f1;
  --color-surface: #ffffff;
  --color-tile: #e4e2de;
  --color-tile-hover: #d9d6d1;
  --color-text: #1a1a1a;
  --color-text-muted: #6b6864;
  --color-border: #e2e0dc;
  --color-accent: #1a1a1a;
  --color-accent-contrast: #ffffff;
  --color-link: #1a1a1a;

  /* Type */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica,
    Arial, sans-serif;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-bold: 700;
  --line-height: 1.6;

  /* Spacing & layout */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2.5rem;
  --space-xl: 4rem;
  --intro-width: 38%;
  --content-max: 1500px;
  --radius: 10px;
  --transition: 0.3s ease;
}

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

html {
  scroll-behavior: smooth;
}

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

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

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

a:hover {
  text-decoration: underline;
}

h1,
h2,
h3 {
  font-weight: var(--font-weight-bold);
  line-height: 1.2;
  margin: 0 0 var(--space-sm);
}

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

/* ---------- Skip link (a11y) ---------- */
.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--color-accent);
  color: var(--color-accent-contrast);
  padding: var(--space-xs) var(--space-sm);
  z-index: 1000;
}
.skip-link:focus {
  left: var(--space-sm);
  top: var(--space-sm);
}

/* ---------- Top nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(244, 243, 241, 0.85);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--color-border);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--content-max);
  margin: 0 auto;
  padding: var(--space-sm) var(--space-lg);
}

.nav__brand {
  font-weight: var(--font-weight-bold);
  font-size: 1.05rem;
  letter-spacing: 0.02em;
}
.nav__brand:hover {
  text-decoration: none;
}

.nav__links {
  display: flex;
  gap: var(--space-md);
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav__link {
  position: relative;
  color: var(--color-text-muted);
  font-size: 0.95rem;
  padding: var(--space-xs) 0;
  transition: color var(--transition);
}
.nav__link:hover {
  color: var(--color-text);
  text-decoration: none;
}
.nav__link.is-active {
  color: var(--color-text);
}
.nav__link.is-active::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -2px;
  width: 100%;
  height: 2px;
  background: var(--color-accent);
}

.nav__toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
}
.nav__toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  transition: transform var(--transition), opacity var(--transition);
  margin: 0 auto;
}
.nav__toggle.is-open span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.nav__toggle.is-open span:nth-child(2) {
  opacity: 0;
}
.nav__toggle.is-open span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ---------- Layout: fixed intro + scrolling content ---------- */
.layout {
  display: flex;
  max-width: var(--content-max);
  margin: 0 auto;
  align-items: flex-start;
}

.intro {
  width: var(--intro-width);
  position: sticky;
  top: 64px;
  align-self: flex-start;
  padding: var(--space-xl) var(--space-lg);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.intro__eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.18em;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  margin: 0;
}

.intro__name {
  font-size: clamp(2.2rem, 4vw, 3.4rem);
  margin: 0;
  letter-spacing: -0.02em;
}

.intro__role {
  font-size: clamp(1.1rem, 1.6vw, 1.4rem);
  font-weight: var(--font-weight-medium);
  color: var(--color-text);
  margin: 0;
}

.intro__bio {
  color: var(--color-text-muted);
  max-width: 42ch;
}

.intro__meta {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  margin-top: var(--space-xs);
  font-size: 0.95rem;
  color: var(--color-text-muted);
}

.intro__meta a {
  color: var(--color-text);
  align-self: flex-start;
  width: fit-content;
}

.content {
  width: calc(100% - var(--intro-width));
  padding: var(--space-xl) var(--space-lg);
  min-height: 70vh;
}

/* ---------- Work tiles ---------- */
.tiles {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-md);
}

.tile {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.tile__media {
  aspect-ratio: 4 / 3;
  background: var(--color-tile);
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-muted);
  font-size: 0.85rem;
  overflow: hidden;
  transition: transform var(--transition), background var(--transition),
    box-shadow var(--transition);
}
.tile__media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.tile:hover .tile__media {
  transform: translateY(-4px);
  background: var(--color-tile-hover);
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.08);
}

.tile--wide {
  grid-column: span 2;
}
.tile--wide .tile__media {
  aspect-ratio: 16 / 9;
}

.tile__caption {
  font-size: 0.9rem;
  color: var(--color-text-muted);
}
.tile__caption strong {
  color: var(--color-text);
  font-weight: var(--font-weight-medium);
}

/* ---------- Generic content sections ---------- */
.page-section {
  max-width: 760px;
  margin-bottom: var(--space-xl);
}

.page-title {
  font-size: clamp(1.8rem, 3vw, 2.6rem);
  margin-bottom: var(--space-md);
}

.section-label {
  text-transform: uppercase;
  letter-spacing: 0.16em;
  font-size: 0.78rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}

.lead {
  font-size: 1.15rem;
  color: var(--color-text);
}

/* ---------- About ---------- */
.about-grid {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: var(--space-lg);
  align-items: start;
}
.about-photo {
  aspect-ratio: 1 / 1;
  background: var(--color-tile);
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-muted);
  font-size: 0.85rem;
}

/* ---------- Buttons ---------- */
.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.7rem 1.3rem;
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-weight: var(--font-weight-medium);
  border: 1px solid var(--color-accent);
  background: var(--color-accent);
  color: var(--color-accent-contrast);
  cursor: pointer;
  transition: opacity var(--transition), transform var(--transition);
}
.btn:hover {
  text-decoration: none;
  opacity: 0.85;
  transform: translateY(-2px);
}
.btn--ghost {
  background: transparent;
  color: var(--color-text);
}

/* ---------- Resume ---------- */
.resume-block {
  margin-bottom: var(--space-lg);
}
.resume-job {
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-md);
  border-bottom: 1px solid var(--color-border);
}
.resume-job:last-child {
  border-bottom: none;
}
.resume-job__head {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: baseline;
  gap: var(--space-xs);
}
.resume-job__title {
  font-size: 1.15rem;
  margin: 0;
}
.resume-job__period {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  white-space: nowrap;
}
.resume-job ul {
  margin: var(--space-xs) 0 0;
  padding-left: 1.2rem;
  color: var(--color-text-muted);
}
.resume-job li {
  margin-bottom: 0.35rem;
}

.skills-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-md);
}
.skill-group h3 {
  font-size: 1rem;
  margin-bottom: 0.4rem;
}
.skill-group p {
  color: var(--color-text-muted);
  font-size: 0.95rem;
  margin: 0;
}

.patent-category {
  font-size: 1rem;
  font-weight: var(--font-weight-bold);
  margin: var(--space-md) 0 var(--space-sm);
}
.patent-category:first-of-type {
  margin-top: 0;
}

.patent {
  margin-bottom: var(--space-md);
}
.patent__title {
  font-size: 1rem;
  font-weight: var(--font-weight-normal);
  margin: 0 0 0.2rem;
}
.patent__meta {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin: 0 0 0.3rem;
}
.patent__desc {
  color: var(--color-text-muted);
  font-size: 0.95rem;
  margin: 0;
}

/* ---------- Contact / form ---------- */
.contact-wrap {
  max-width: 520px;
}

.form-field {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  margin-bottom: var(--space-sm);
}
.form-field label {
  font-size: 0.9rem;
  font-weight: var(--font-weight-medium);
}
.form-field input,
.form-field textarea {
  font-family: inherit;
  font-size: 1rem;
  padding: 0.7rem 0.85rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  color: var(--color-text);
  transition: border-color var(--transition);
}
.form-field input:focus,
.form-field textarea:focus {
  outline: none;
  border-color: var(--color-accent);
}
.form-field textarea {
  resize: vertical;
  min-height: 140px;
}

/* honeypot — hidden from humans */
.hp-field {
  position: absolute;
  left: -5000px;
  width: 1px;
  height: 1px;
  overflow: hidden;
}

.form-status {
  margin-top: var(--space-sm);
  font-size: 0.95rem;
  min-height: 1.4em;
}
.form-status.is-success {
  color: #1f7a44;
}
.form-status.is-error {
  color: #b3261e;
}

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--color-border);
  margin-top: var(--space-xl);
}
.site-footer__inner {
  max-width: var(--content-max);
  margin: 0 auto;
  padding: var(--space-lg);
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  justify-content: space-between;
  align-items: center;
  color: var(--color-text-muted);
  font-size: 0.9rem;
}
.site-footer__links {
  display: flex;
  gap: var(--space-md);
}

/* ---------- Scroll reveal ---------- */
.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal.is-visible {
  opacity: 1;
  transform: none;
}

/* ---------- Responsive ---------- */
@media (max-width: 1024px) {
  .tiles {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 880px) {
  .nav {
    padding: var(--space-sm) var(--space-md);
    position: relative;
  }
  .nav__toggle {
    display: flex;
  }
  .nav__links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-xs) var(--space-md);
    transform: scaleY(0);
    transform-origin: top;
    opacity: 0;
    pointer-events: none;
    transition: transform var(--transition), opacity var(--transition);
  }
  .nav__links.is-open {
    transform: scaleY(1);
    opacity: 1;
    pointer-events: auto;
  }
  .nav__link {
    padding: var(--space-sm) 0;
    border-bottom: 1px solid var(--color-border);
  }
  .nav__link:last-child {
    border-bottom: none;
  }
  .nav__link.is-active::after {
    display: none;
  }

  .layout {
    flex-direction: column;
  }
  .intro,
  .content {
    width: 100%;
    position: static;
    padding: var(--space-lg) var(--space-md);
  }
  .intro {
    padding-bottom: 0;
  }
  .content {
    padding-top: var(--space-md);
  }

  .contact-wrap {
    max-width: none;
  }
  .about-grid {
    grid-template-columns: 1fr;
  }
  .about-photo {
    max-width: 200px;
  }
}

@media (max-width: 560px) {
  .tiles {
    grid-template-columns: 1fr;
  }
  .tile--wide {
    grid-column: span 1;
  }
  .skills-grid {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    scroll-behavior: auto !important;
  }
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
}