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

:root {
  --sidebar-width: 240px;
  --gap: 6px;
  --font: "Helvetica Neue", Helvetica, Arial, sans-serif;
}

:root,
[data-theme="light"] {
  --bg: #f8f8f8;
  --text: #1a1a1a;
  --text-muted: #777;
  --accent: #111;
  --border: #e5e5e5;
  --text-body: #444;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0a0a0a;
    --text: #f0f0f0;
    --text-muted: #888;
    --accent: #fff;
    --border: #1a1a1a;
    --text-body: #ccc;
    color-scheme: dark;
  }
}

[data-theme="dark"] {
  --bg: #0a0a0a;
  --text: #f0f0f0;
  --text-muted: #888;
  --accent: #fff;
  --border: #1a1a1a;
  --text-body: #ccc;
  color-scheme: dark;
}

html {
  font-size: 14px;
}

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
}

a {
  color: inherit;
  text-decoration: none;
}

/* ── Sidebar ── */

.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-width);
  height: 100vh;
  background: var(--bg);
  display: flex;
  flex-direction: column;
  padding: 48px 32px 32px;
  z-index: 100;
  border-right: 1px solid var(--border);
}

.brand h1 {
  font-size: 0.95rem;
  font-weight: 400;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  line-height: 1.5;
}

.nav {
  margin-top: 48px;
  flex: 1;
}

.nav ul {
  list-style: none;
}

.nav li {
  margin-bottom: 2px;
}

.nav a {
  display: block;
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  padding: 8px 0 8px 16px;
  color: var(--text-muted);
  transition: color 0.2s;
  position: relative;
}

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

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

.nav a.active::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 2px;
  height: 14px;
  background: var(--accent);
}

.nav-section {
  margin-top: 24px;
}

.nav-section-label {
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  padding: 8px 0 8px 16px;
  color: var(--text);
  font-weight: 400;
}

.sidebar-footer {
  margin-top: auto;
  padding-top: 32px;
}

.theme-toggle {
  display: flex;
  align-items: center;
  gap: 10px;
  background: none;
  border: none;
  color: var(--text-muted);
  font-family: var(--font);
  font-size: 0.65rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  cursor: pointer;
  padding: 0 0 20px;
  transition: color 0.2s;
}

.theme-toggle:hover {
  color: var(--text);
}

.theme-toggle-icon {
  width: 14px;
  height: 14px;
  fill: currentColor;
  flex-shrink: 0;
}

.social-links {
  display: flex;
  gap: 16px;
  margin-bottom: 20px;
}

.social-links a {
  color: var(--text-muted);
  transition: color 0.2s;
}

.social-links a:hover {
  color: var(--text);
}

.social-links svg {
  width: 16px;
  height: 16px;
  fill: currentColor;
}

.copyright {
  font-size: 0.6rem;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ── Main content ── */

.main {
  margin-left: var(--sidebar-width);
  flex: 1;
  min-height: 100vh;
}

/* ── Text pages (home, about) ── */

.text-content {
  max-width: 640px;
  padding: 64px 48px;
}

.text-content h2 {
  font-size: 0.75rem;
  letter-spacing: 0.25em;
  text-transform: uppercase;
  font-weight: 400;
  margin-bottom: 32px;
  color: var(--text-muted);
}

.text-content p {
  font-size: 0.95rem;
  line-height: 1.8;
  color: var(--text-body);
  margin-bottom: 1.4em;
}

/* ── Masonry gallery ── */

.gallery {
  columns: 3;
  column-gap: var(--gap);
  padding: var(--gap);
}

.gallery-item {
  break-inside: avoid;
  margin-bottom: var(--gap);
  overflow: hidden;
  line-height: 0;
}

.gallery-item img {
  width: 100%;
  height: auto;
  display: block;
  filter: grayscale(100%);
  transition: filter 0.4s ease, transform 0.4s ease;
}

.gallery-item:hover img {
  filter: grayscale(0%);
  transform: scale(1.02);
}

/* ── Responsive ── */

@media (max-width: 900px) {
  .gallery {
    columns: 2;
  }
}

@media (max-width: 640px) {
  :root {
    --sidebar-width: 100%;
  }

  body {
    flex-direction: column;
  }

  .sidebar {
    position: relative;
    width: 100%;
    height: auto;
    padding: 24px;
    border-right: none;
    border-bottom: 1px solid var(--border);
  }

  .nav {
    margin-top: 24px;
  }

  .sidebar-footer {
    display: block;
    padding-top: 16px;
  }

  .sidebar-footer .social-links,
  .sidebar-footer .copyright {
    display: none;
  }

  .theme-toggle {
    padding-bottom: 0;
  }

  .main {
    margin-left: 0;
  }

  .gallery {
    columns: 1;
  }

  .text-content {
    padding: 32px 24px;
  }
}