/* ============================================================
   KEVIN KRILL — PORTFOLIO STYLESHEET
   Structure:
   1. Design Tokens (CSS variables — change these to retheme)
   2. Reset & Base
   3. Utilities
   4. Navigation
   5. Hero
   6. About
   7. Projects
   8. Skills
   9. Experience / Timeline
   10. Contact
   11. Footer
   12. Animations
   ============================================================ */


/* ============================================================
   1. DESIGN TOKENS
   All colors, sizes, and spacing live here.
   Change a value here and it updates the entire site.
   ============================================================ */
:root {
  /* Color palette — Modern Professional (blue/navy) */
  --color-bg:           #0a0f1e;   /* Deep navy background */
  --color-surface:      #111827;   /* Card / nav surface */
  --color-surface-2:    #1e293b;   /* Elevated surface (tags, hover) */
  --color-primary:      #6366f1;   /* Indigo accent */
  --color-primary-h:    #818cf8;   /* Lighter indigo on hover */
  --color-text:         #e2e8f0;   /* Primary text */
  --color-text-muted:   #94a3b8;   /* Secondary / subdued text */
  --color-border:       #1e293b;   /* Subtle borders */

  /* Typography */
  --font-display: 'Plus Jakarta Sans', -apple-system, sans-serif;
  --font-body:    'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono:    'SF Mono', 'Fira Code', 'Roboto Mono', Consolas, monospace;

  /* Type scale */
  --text-xs:   0.75rem;    /* 12px */
  --text-sm:   0.875rem;   /* 14px */
  --text-base: 1rem;       /* 16px */
  --text-lg:   1.125rem;   /* 18px */
  --text-xl:   1.25rem;    /* 20px */
  --text-2xl:  1.5rem;     /* 24px */
  --text-3xl:  1.875rem;   /* 30px */
  --text-4xl:  2.25rem;    /* 36px */
  --text-5xl:  3rem;       /* 48px */

  /* Spacing (base-8 system — multiples of 8px) */
  --space-1:  0.25rem;   /* 4px */
  --space-2:  0.5rem;    /* 8px */
  --space-3:  0.75rem;   /* 12px */
  --space-4:  1rem;      /* 16px */
  --space-6:  1.5rem;    /* 24px */
  --space-8:  2rem;      /* 32px */
  --space-12: 3rem;      /* 48px */
  --space-16: 4rem;      /* 64px */
  --space-24: 6rem;      /* 96px */

  /* Layout */
  --max-width:  1100px;
  --nav-height: 4rem;     /* Used to offset section scroll position */

  /* Borders */
  --radius-sm:   0.375rem;
  --radius-md:   0.5rem;
  --radius-lg:   1rem;
  --radius-xl:   1.5rem;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-card:       0 4px 24px rgba(0, 0, 0, 0.35);
  --shadow-card-hover: 0 8px 40px rgba(99, 102, 241, 0.25);

  /* Transitions */
  --t-fast:   150ms ease;
  --t-normal: 250ms ease;
  --t-slow:   400ms ease;
}


/* ============================================================
   2. RESET & BASE
   ============================================================ */

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
  color-scheme: dark;
}

/* Kill all animations for users who prefer reduced motion */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.7;
  background-color: var(--color-bg);
  color: var(--color-text);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img, picture, video, canvas, svg {
  display: block;
  max-width: 100%;
  height: auto;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--t-fast);
}

a:hover { color: var(--color-primary-h); }

/* Keyboard focus ring — visible only when navigating with keyboard */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}


/* ============================================================
   3. UTILITIES
   ============================================================ */

/* Sections: consistent vertical rhythm + scroll-margin so sticky nav
   doesn't cover the heading when you click a nav anchor */
.section {
  padding: var(--space-24) var(--space-6);
  scroll-margin-top: var(--nav-height);
  max-width: var(--max-width);
  margin-inline: auto;
}

.section__title {
  font-family: var(--font-display);
  font-size: var(--text-3xl);
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-12);
  position: relative;
  display: inline-block;
}

/* Accent underline on section headings */
.section__title::after {
  content: '';
  display: block;
  width: 3rem;
  height: 3px;
  background: var(--color-primary);
  margin-top: var(--space-3);
  border-radius: var(--radius-full);
}

/* Skill/tech tag pill */
.tag {
  display: inline-block;
  padding: var(--space-1) var(--space-3);
  background-color: var(--color-surface-2);
  color: var(--color-primary);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  border-radius: var(--radius-full);
  white-space: nowrap;
}

/* Accessibility: skip-to-content link */
.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-4);
  padding: var(--space-3) var(--space-6);
  background: var(--color-primary);
  color: #fff;
  font-weight: 600;
  border-radius: 0 0 var(--radius-md) var(--radius-md);
  z-index: 1000;
  transition: top var(--t-fast);
}
.skip-link:focus { top: 0; }


/* ============================================================
   4. BUTTONS
   ============================================================ */

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: 600;
  border-radius: var(--radius-md);
  border: 2px solid transparent;
  cursor: pointer;
  transition:
    background-color var(--t-fast),
    color var(--t-fast),
    border-color var(--t-fast),
    transform var(--t-fast),
    box-shadow var(--t-fast);
  text-decoration: none;
  white-space: nowrap;
}

.btn:hover  { transform: translateY(-2px); }
.btn:active { transform: translateY(0); }

.btn--primary {
  background-color: var(--color-primary);
  color: #fff;
}
.btn--primary:hover {
  background-color: var(--color-primary-h);
  color: #fff;
  box-shadow: 0 4px 20px rgba(99, 102, 241, 0.4);
}

.btn--secondary {
  background-color: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}
.btn--secondary:hover {
  background-color: var(--color-primary);
  color: #fff;
}

.btn--sm  { padding: var(--space-2) var(--space-4); font-size: var(--text-sm); }
.btn--lg  { padding: var(--space-4) var(--space-8); font-size: var(--text-lg); }


/* ============================================================
   5. NAVIGATION
   ============================================================ */

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-height);
  background-color: rgba(10, 15, 30, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: var(--space-6);
  gap: var(--space-6);
}

.nav__logo {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 800;
  color: var(--color-text);
  letter-spacing: -0.02em;
  flex-shrink: 0;
}
.nav__logo:hover { color: var(--color-primary); }

.nav__menu {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  list-style: none;
}

.nav__link {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  font-weight: 500;
  letter-spacing: 0.04em;
  transition: color var(--t-fast);
}

.nav__link:hover,
.nav__link.active {
  color: var(--color-primary);
}

/* Hamburger toggle — hidden on desktop */
.nav__toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-2);
  flex-shrink: 0;
}

.hamburger-bar {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--color-text);
  border-radius: var(--radius-full);
  transition: transform var(--t-normal), opacity var(--t-normal);
}

/* Animate bars into an × when menu is open */
.nav__toggle[aria-expanded="true"] .hamburger-bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.nav__toggle[aria-expanded="true"] .hamburger-bar:nth-child(2) {
  opacity: 0;
}
.nav__toggle[aria-expanded="true"] .hamburger-bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Mobile menu */
@media (max-width: 768px) {
  .nav__toggle { display: flex; }

  .nav__menu {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: center;
    gap: var(--space-8);
    padding: var(--space-12) var(--space-6);
    background-color: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    /* Hidden state */
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: transform var(--t-normal), opacity var(--t-normal);
  }

  .nav__menu.is-open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .nav__link { font-size: var(--text-lg); }
}


/* ============================================================
   6. HERO
   ============================================================ */

.hero {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: var(--space-12);
  min-height: calc(100svh - var(--nav-height));
  padding: var(--space-16) var(--space-6);
  max-width: var(--max-width);
  margin-inline: auto;
  justify-content: center;
}

@media (min-width: 768px) {
  .hero {
    flex-direction: row;
    text-align: left;
    justify-content: space-between;
  }
}

.hero__content {
  max-width: 600px;
}

.hero__eyebrow {
  font-family: var(--font-mono);
  font-size: var(--text-base);
  color: var(--color-primary);
  margin-bottom: var(--space-3);
}

.hero__name {
  font-family: var(--font-display);
  /* clamp(min, fluid, max) — fluid type that scales with viewport, no media queries */
  font-size: clamp(var(--text-4xl), 8vw, var(--text-5xl));
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: var(--space-4);
  color: var(--color-text);
}

.hero__title {
  font-size: clamp(var(--text-xl), 4vw, var(--text-2xl));
  color: var(--color-text-muted);
  font-weight: 500;
  margin-bottom: var(--space-4);
}

.hero__tagline {
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  line-height: 1.7;
  max-width: 44ch;
  margin-bottom: var(--space-8);
}

.hero__actions {
  display: flex;
  gap: var(--space-4);
  flex-wrap: wrap;
  justify-content: center;
}

@media (min-width: 768px) {
  .hero__actions { justify-content: flex-start; }
}

/* Avatar — real photo or placeholder initials */
.avatar {
  width: min(280px, 60vw);
  height: min(280px, 60vw);
  border-radius: var(--radius-full);
  border: 3px solid var(--color-primary);
  box-shadow: 0 0 60px rgba(99, 102, 241, 0.3);
  object-fit: cover;
  flex-shrink: 0;
}

/* Placeholder shown until a real photo is added */
.avatar--placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-surface-2);
  color: var(--color-primary);
  font-family: var(--font-display);
  font-size: var(--text-4xl);
  font-weight: 800;
  letter-spacing: -0.02em;
  user-select: none;
}


/* ============================================================
   7. ABOUT
   ============================================================ */

.about__content {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  max-width: 65ch;
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  line-height: 1.8;
}


/* ============================================================
   8. PROJECTS
   ============================================================ */

.projects__grid {
  display: grid;
  /* auto-fill: browser creates as many columns as fit.
     minmax(300px, 1fr): each column is at least 300px, at most equal share.
     Result: responsive grid with zero media queries. */
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--space-8);
}

.project-card {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition:
    transform var(--t-normal),
    box-shadow var(--t-normal),
    border-color var(--t-normal);

  /* Scroll-reveal starting state — JS adds .is-visible */
  opacity: 0;
  transform: translateY(24px);
}

.project-card.is-visible {
  opacity: 1;
  transform: translateY(0);
  transition:
    opacity var(--t-slow),
    transform var(--t-slow),
    box-shadow var(--t-normal),
    border-color var(--t-normal);
}

.project-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-card-hover);
  border-color: var(--color-primary);
}

/* Image area */
.project-card__image-wrap {
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: var(--color-surface-2);
}

.project-card__image-wrap--placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary);
  font-family: var(--font-mono);
  font-size: var(--text-3xl);
  font-weight: 700;
  letter-spacing: 0.1em;
}

.project-card__img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--t-slow);
}
.project-card:hover .project-card__img { transform: scale(1.04); }

/* Card body */
.project-card__body {
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  flex: 1;
}

.project-card__title {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-text);
}

.project-card__desc {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: 1.75;
  flex: 1;
}

.project-card__tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  list-style: none;
}

.project-card__links {
  display: flex;
  gap: var(--space-3);
  margin-top: auto;
  padding-top: var(--space-2);
}

/* Muted style for placeholder/coming-soon card */
.project-card--coming-soon {
  opacity: 0.6;
  border-style: dashed;
}
.project-card--coming-soon.is-visible {
  opacity: 0.6;
}


/* ============================================================
   9. SKILLS
   ============================================================ */

.skills__groups {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: var(--space-8);
}

.skills__group-title {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-primary);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-2);
  border-bottom: 1px solid var(--color-border);
}

.skills__list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.skill-item {
  font-size: var(--text-base);
  color: var(--color-text-muted);
  display: flex;
  align-items: center;
  gap: var(--space-2);
  transition: color var(--t-fast);
}

/* Decorative arrow bullet via CSS pseudo-element */
.skill-item::before {
  content: '▸';
  color: var(--color-primary);
  font-size: var(--text-sm);
  flex-shrink: 0;
}

.skill-item:hover { color: var(--color-text); }


/* ============================================================
   10. EXPERIENCE / TIMELINE
   ============================================================ */

.timeline {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: var(--space-12);
  padding-left: var(--space-8);
}

/* The vertical line */
.timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 8px;
  bottom: 0;
  width: 2px;
  background: var(--color-border);
  border-radius: var(--radius-full);
}

.timeline__entry {
  position: relative;
}

/* The dot on the line */
.timeline__marker {
  position: absolute;
  left: calc(-1 * var(--space-8) - 5px);
  top: 8px;
  width: 12px;
  height: 12px;
  border-radius: var(--radius-full);
  background: var(--color-primary);
  border: 2px solid var(--color-bg);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.3);
}

.timeline__content {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.timeline__header {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.timeline__role {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-text);
}

.timeline__company {
  font-size: var(--text-base);
  color: var(--color-primary);
  font-weight: 500;
}

.timeline__dates {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.timeline__bullets {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  padding-left: var(--space-4);
}

.timeline__bullets li {
  color: var(--color-text-muted);
  font-size: var(--text-base);
  position: relative;
}

.timeline__bullets li::before {
  content: '–';
  position: absolute;
  left: calc(-1 * var(--space-4));
  color: var(--color-primary);
}


/* ============================================================
   11. CONTACT
   ============================================================ */

.contact {
  text-align: center;
}

.contact__lead {
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  max-width: 52ch;
  margin-inline: auto;
  margin-bottom: var(--space-8);
  line-height: 1.8;
}

.contact__socials {
  display: flex;
  justify-content: center;
  gap: var(--space-6);
  list-style: none;
  margin-top: var(--space-8);
}

.contact__socials a {
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
  transition: color var(--t-fast);
}
.contact__socials a:hover { color: var(--color-primary); }


/* ============================================================
   12. FOOTER
   ============================================================ */

.site-footer {
  text-align: center;
  padding: var(--space-8) var(--space-6);
  border-top: 1px solid var(--color-border);
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  font-family: var(--font-mono);
}


/* ============================================================
   13. SCROLL-REVEAL ANIMATIONS
   Elements start invisible (set on the element itself for project
   cards; this handles other animated elements if added later).
   ============================================================ */

.fade-up {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity var(--t-slow), transform var(--t-slow);
}

.fade-up.is-visible {
  opacity: 1;
  transform: translateY(0);
}