/* =============================================
   DESIGN TOKENS
   ============================================= */
:root {
  --bg: #f4f3f0;
  --ink: #111110;
  --muted: #706e69;
  --accent: #1a56db;
  --surface: #eceae6;
  --line: #dcdad6;

  --font-head: "Syne", system-ui, sans-serif;
  --font-body: "Inter", system-ui, sans-serif;
  --font-mono: "Fragment Mono", "Courier New", mono;

  --max: 740px;
  --max-wide: 980px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.7;
  font-weight: 300;
  -webkit-font-smoothing: antialiased;
}

img {
  display: block;
  max-width: 100%;
  border-radius: 3px;
}

p {
  margin-bottom: 1.15em;
}

p:last-child {
  margin-bottom: 0;
}

.wrap {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.wrap-wide {
  max-width: var(--max-wide);
  margin: 0 auto;
  padding: 0 1.5rem;
}

section {
  padding: 5.5rem 0;
}

/* =============================================
   TYPOGRAPHY
   ============================================= */
h1 {
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(2.6rem, 6vw, 4rem);
  line-height: 1.05;
  letter-spacing: -0.02em;
}

h2 {
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(1.6rem, 3.5vw, 2.2rem);
  line-height: 1.1;
  letter-spacing: -0.015em;
}

/* mono label */
.mono {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--accent);
  letter-spacing: 0.04em;
}

/* section label */
.label {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin-bottom: 1rem;
}

.label .mono {
  color: var(--accent);
}

.label::before {
  content: "";
  display: block;
  width: 8px;
  height: 8px;
  background: var(--accent);
  border-radius: 1px;
  flex-shrink: 0;
}

/* tag */
.tag {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  padding: 3px 8px;
  border: 1px solid var(--line);
  color: var(--muted);
  border-radius: 2px;
  letter-spacing: 0.04em;
}

.tag-accent {
  border-color: var(--accent);
  color: var(--accent);
}

/* fade-in animation */
.fade {
  opacity: 0;
  transform: translateY(18px);
  transition:
    opacity 0.6s ease,
    transform 0.6s ease;
}

.fade.in {
  opacity: 1;
  transform: none;
}

/* =============================================
   NAV
   ============================================= */
nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: var(--bg);
  border-bottom: 1px solid var(--line);
}

nav .wrap-wide {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 0.9rem;
  padding-bottom: 0.9rem;
}

.nav-name {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  text-decoration: none;
  color: var(--accent);
  display: flex;
  align-items: center;
}

.nav-name svg {
  height: 18px;
  width: auto;
  display: block;
}

.nav-links {
  display: flex;
  gap: 2rem;
  list-style: none;
}

.nav-links a {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--muted);
  text-decoration: none;
  transition: color 0.2s;
}

.nav-links a:hover {
  color: var(--accent);
}

/* =============================================
   HERO
   ============================================= */
.hero {
  padding-top: calc(5rem + 56px);
  padding-bottom: 5rem;
  border-bottom: 1px solid var(--line);
}

.hero-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 2rem;
  flex-wrap: wrap;
  gap: 1rem;
}

.hero-index {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--muted);
  padding: 4px 10px;
  border: 1px solid var(--line);
  border-radius: 2px;
  white-space: nowrap;
  align-self: flex-start;
}

.hero h1 {
  margin-bottom: 1.2rem;
  max-width: 580px;
}

.hero h1 span {
  color: var(--accent);
}

.hero-desc {
  color: var(--muted);
  max-width: 440px;
  font-size: 0.95rem;
  margin-bottom: 2.5rem;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

/* =============================================
   LETTER
   ============================================= */
#dopis {
  background: var(--surface);
}

.letter-head {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 2rem;
  align-items: start;
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--line);
  margin-bottom: 2.5rem;
  flex-wrap: wrap;
}

.letter-date {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--muted);
  line-height: 2;
  text-align: right;
  white-space: nowrap;
}

.letter-body p {
  font-size: 0.94rem;
  margin-bottom: 1.4em;
  text-align: justify;
  hyphens: auto;
}

.letter-sign {
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--muted);
}

.letter-sign strong {
  display: block;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.2rem;
  color: var(--ink);
  margin-top: 0.5rem;
  letter-spacing: -0.01em;
}

/* =============================================
   PORTFOLIO
   ============================================= */
.portfolio-head {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: end;
  margin-bottom: 4rem;
}

.portfolio-head p {
  color: var(--muted);
  font-size: 0.88rem;
}

/* case study */
.case {
  border-top: 2px solid var(--ink);
  padding-top: 3rem;
  margin-bottom: 5rem;
  position: relative;
}

.case:last-child {
  margin-bottom: 0;
}

.case-num {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--muted);
  position: absolute;
  top: 3rem;
  right: 0;
}

.case-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 1.2rem;
}

.case h2 {
  margin-bottom: 2rem;
  max-width: 780px;
}

.case-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2.5rem;
  margin-bottom: 2.5rem;
}

.case-grid p {
  font-size: 0.87rem;
}

.detail {
  margin-bottom: 1.4rem;
}

.detail-label {
  font-family: var(--font-mono);
  font-size: 0.67rem;
  color: var(--muted);
  margin-bottom: 5px;
  letter-spacing: 0.04em;
}

/* process steps */
.process {
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  margin: 1.5rem 0;
}

.step {
  display: flex;
  align-items: center;
  gap: 5px;
  font-family: var(--font-mono);
  font-size: 0.67rem;
  color: var(--muted);
}

.step.done {
  color: var(--accent);
}

.step::after {
  content: "→";
  color: var(--line);
  margin: 0 5px;
}

.step:last-child::after {
  display: none;
}

.step-dot {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--line);
  flex-shrink: 0;
}

.step.done .step-dot {
  background: var(--accent);
}

/* image grid */
.img-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin-top: 2rem;
}

.img-box {
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 3px;
  aspect-ratio: 4/3;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
}

.img-box::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 24px 24px;
  opacity: 0.2;
}

.img-box img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: 1;
}

.img-box span {
  position: relative;
  z-index: 2;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--muted);
  letter-spacing: 0.04em;
}

/* =============================================
   FOOTER
   ============================================= */
footer {
  border-top: 1px solid var(--line);
  padding: 1.5rem 0;
}

.footer-row {
  display: flex;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--muted);
}

/* =============================================
   LIGHTBOX
   ============================================= */
.lightbox {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 200;
  background: rgba(17, 17, 16, 0.92);
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
  cursor: zoom-out;
}

.lightbox.open {
  display: flex;
}

.lightbox-img {
  max-width: 100%;
  max-height: 90vh;
  width: auto;
  height: auto;
  border-radius: 4px;
  box-shadow: 0 8px 48px rgba(0, 0, 0, 0.5);
  cursor: default;
}

.lightbox-close {
  position: fixed;
  top: 1.25rem;
  right: 1.5rem;
  background: none;
  border: 1px solid rgba(255, 255, 255, 0.2);
  color: #fff;
  font-size: 1.4rem;
  line-height: 1;
  width: 2.2rem;
  height: 2.2rem;
  border-radius: 3px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s;
}

.lightbox-close:hover {
  background: rgba(255, 255, 255, 0.12);
}

.img-box img {
  cursor: zoom-in;
}

/* =============================================
   RESPONSIVE
   ============================================= */
@media (max-width: 600px) {
  /* Nav */
  nav .wrap-wide {
    padding-top: 0.7rem;
    padding-bottom: 0.7rem;
  }

  .nav-links {
    gap: 1.2rem;
  }

  .nav-name svg {
    height: 14px;
  }

  /* Hero */
  h1 {
    font-size: clamp(1.7rem, 7vw, 2.6rem);
  }

  .hero {
    padding-top: calc(3.5rem + 46px);
    padding-bottom: 3rem;
  }

  .hero-top {
    flex-direction: column;
  }

  .hero-desc {
    font-size: 0.88rem;
  }

  /* Layout */
  .portfolio-head,
  .case-grid,
  .img-grid {
    grid-template-columns: 1fr;
  }

  .case-num {
    display: none;
  }

  .letter-head {
    grid-template-columns: 1fr;
  }

  .letter-date {
    text-align: left;
  }

  /* Footer */
  .footer-row {
    flex-direction: column;
    gap: 0.4rem;
  }
}