/* ── Custom Properties ── */
:root {
  --gap: 84px;
  --gutter: max(64px, 12vw);
  --font-body: "Nanum Myeongjo", serif;
  --color-bg: #fff;
  --color-text: #111;
  --header-height: 60px;
}

/* ── Base ── */
body {
  font-family: var(--font-body);
  color: var(--color-text);
  background: var(--color-bg);
}

/* ── Header ── */
.site-header {
  position: relative;
  z-index: 100;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 2.5rem var(--gutter) 0.5rem;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.site-title {
  font-size: 1.5rem;
  font-weight: 400;
  letter-spacing: 0.02em;
  text-decoration: none;
}

/* ── Navigation ── */
.nav-links {
  display: flex;
  gap: 2.5rem;
}

.nav-links a {
  font-size: 1.1rem;
  letter-spacing: 0.02em;
  text-decoration: none;
  opacity: 0.45;
  transition: opacity 0.2s;
}

.nav-links a:hover,
.nav-links a.active {
  opacity: 1;
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  flex-direction: column;
  gap: 5px;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 1.5px;
  background: var(--color-text);
  transition: transform 0.3s, opacity 0.3s;
}

/* ── Page Title ── */
.page-title {
  font-size: 3rem;
  font-weight: 400;
  padding: 6rem var(--gutter) 7rem;
  opacity: 0;
  transform: translateY(20px);
  animation: fadeSlideIn 1s ease forwards;
}

@keyframes fadeSlideIn {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ── Photo Grid (masonry via CSS columns) ── */
.photo-grid {
  columns: 1;
  column-gap: var(--gap);
  padding: 0 var(--gutter) var(--gutter);
}

.photo-item {
  break-inside: avoid;
  overflow: hidden;
  cursor: pointer;
  position: relative;
  padding-bottom: var(--gap);
}

.photo-item {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 1s ease, transform 1s ease;
}

.photo-item.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.photo-item img {
  width: 100%;
  height: auto;
  display: block;
}

@media (min-width: 768px) {
  .photo-grid {
    columns: 2;
  }
}

@media (min-width: 1200px) {
  .photo-grid {
    columns: 3;
  }
}

/* ── Lightbox ── */
.lightbox {
  position: fixed;
  inset: 0;
  z-index: 1000;
  background: rgb(245, 245, 243);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity 0.4s ease;
  pointer-events: none;
  overflow: hidden;
  -webkit-overflow-scrolling: touch;
  height: 100%;
  height: 100dvh;
}

.lightbox.is-open {
  opacity: 1;
  pointer-events: auto;
}

body.lightbox-open .photo-grid,
body.lightbox-open .page-title,
body.lightbox-open .site-header {
  visibility: hidden;
}

.lightbox-img {
  max-width: 88vw;
  max-height: 88vh;
  object-fit: contain;
  opacity: 1;
  transition: opacity 0.35s ease;
}

.lightbox-img.is-fading {
  opacity: 0;
}

.lightbox-close,
.lightbox-prev,
.lightbox-next {
  position: absolute;
  background: none;
  border: none;
  color: rgba(0, 0, 0, 0.6);
  padding: 1.5rem;
  transition: color 0.2s;
  line-height: 0;
}

.lightbox-close svg,
.lightbox-prev svg,
.lightbox-next svg {
  width: 24px;
  height: 24px;
}

.lightbox-close:hover,
.lightbox-prev:hover,
.lightbox-next:hover {
  color: rgba(0, 0, 0, 0.7);
}

.lightbox-close {
  top: 0.8rem;
  right: 1rem;
}

.lightbox-prev {
  left: 1rem;
  top: 50%;
  transform: translateY(-50%);
}

.lightbox-next {
  right: 1rem;
  top: 50%;
  transform: translateY(-50%);
}

.lightbox-counter {
  display: none;
}

/* ── Mobile Lightbox ── */
@media (max-width: 767px) {
  .lightbox {
    display: grid;
    grid-template-columns: 1fr 1fr;
    grid-template-rows: 1fr auto;
    place-items: center;
  }

  .lightbox-img {
    grid-column: 1 / -1;
    grid-row: 1;
    max-width: 92vw;
    max-height: 70vh;
  }

  .lightbox-close {
    grid-column: 1 / -1;
    grid-row: 1;
    align-self: start;
    justify-self: end;
  }

  .lightbox-prev,
  .lightbox-next {
    position: static;
    transform: none;
    grid-row: 2;
  }

  .lightbox-prev {
    justify-self: end;
  }

  .lightbox-next {
    justify-self: start;
  }
}

/* ── Mobile Navigation ── */
@media (max-width: 767px) {
  .nav-toggle {
    display: flex;
    z-index: 200;
    position: relative;
  }

  .nav-links {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    width: 100vw;
    height: 100vh;
    background: #fff;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 2.5rem;
    z-index: 150;
    margin: 0;
    padding: 0;
  }

  .nav-links.is-open {
    display: flex;
  }

  .page-title {
    padding: 4rem var(--gutter) 5rem;
  }

  .nav-links a {
    font-size: 1.2rem;
    opacity: 0.7;
  }

  .nav-toggle.is-open span:nth-child(1) {
    transform: translateY(6.5px) rotate(45deg);
  }

  .nav-toggle.is-open span:nth-child(2) {
    opacity: 0;
  }

  .nav-toggle.is-open span:nth-child(3) {
    transform: translateY(-6.5px) rotate(-45deg);
  }
}