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

:root {
  --color-bg: #ffffff;
  --color-text: #333333;
  --color-gray: #666666;
  --color-light: #999999;
  --color-border: #e0e0e0;
  --font-main:
    -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --sidebar-width: 280px;
}

html,
body {
  height: 100%;
}

body {
  font-family: var(--font-main);
  font-size: 14px;
  line-height: 1.5;
  color: var(--color-text);
  background: var(--color-bg);
}

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

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

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

/* Layout */
.layout {
  display: flex;
  min-height: 100vh;
  max-width: 1200px;
  margin: 0 auto;
}

/* Sidebar */
.sidebar {
  width: var(--sidebar-width);
  min-width: var(--sidebar-width);
  min-height: 100vh;
  padding: 2rem;
  display: flex;
  flex-direction: column;
  position: sticky;
  top: 0;
  align-self: flex-start;
  overflow-y: auto;
  max-height: 100vh;
}

.site-header {
  margin-bottom: 2rem;
}

.logo {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-text);
}

/* Navigation */
.main-nav {
  flex: 1;
}

.nav-category {
  margin-bottom: 0.5rem;
}

.nav-category-title {
  display: block;
  padding: 0.25rem 0;
  color: var(--color-gray);
  font-size: 0.95rem;
}

.nav-category-title:hover,
.nav-category-title.is-active {
  color: var(--color-text);
}

.nav-category.is-open .nav-category-title {
  color: var(--color-text);
  font-weight: 500;
}

.nav-projects {
  list-style: none;
  margin: 0.25rem 0 1rem 0;
  padding-left: 1rem;
}

.nav-projects li {
  margin: 0.2rem 0;
}

.nav-projects a {
  color: var(--color-light);
  font-size: 0.85rem;
}

.nav-projects a:hover,
.nav-projects a.is-active {
  color: var(--color-text);
}

/* Footer in Sidebar */
.site-footer {
  margin-top: auto;
  padding-top: 2rem;
  font-size: 0.8rem;
  color: var(--color-light);
}

.site-footer a {
  color: var(--color-light);
}

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

/* Content Area */
.content {
  flex: 1;
  padding: 2rem;
  min-height: 100vh;
}

/* Home - Featured Project */
.featured-project {
  height: calc(100vh - 4rem);
  display: flex;
  align-items: center;
  justify-content: center;
}

.featured-project img {
  max-height: 100%;
  max-width: 100%;
  object-fit: contain;
}

/* Category Page - Projects Grid */
.category-header {
  margin-bottom: 2rem;
}

.category-header h1 {
  font-size: 1.25rem;
  font-weight: 500;
}

.projects-grid {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1.5rem;
}

.project-card figure {
  aspect-ratio: 4/3;
  overflow: hidden;
  background: #f5f5f5;
  margin-bottom: 0.5rem;
}

.project-card img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.3s ease;
}

.project-card a:hover img {
  transform: scale(1.03);
}

.project-card h2 {
  font-size: 0.9rem;
  font-weight: 400;
  color: var(--color-gray);
}

.project-card .year {
  font-size: 0.8rem;
  color: var(--color-light);
}

/* Project Page */
.project-header {
  margin-bottom: 2rem;
}

.project-header h1 {
  font-size: 1.25rem;
  font-weight: 500;
  margin-bottom: 0.25rem;
}

.project-header .meta,
.project-header .materials {
  font-size: 0.9rem;
  color: var(--color-gray);
}

.gallery {
  margin-bottom: 2rem;
}

.gallery figure {
  margin-bottom: 1rem;
}

.gallery img {
  max-height: 80vh;
  width: auto;
}

.description {
  max-width: 600px;
  color: var(--color-gray);
  font-size: 0.95rem;
  line-height: 1.6;
}

.description p {
  margin-bottom: 1em;
}

.project-nav {
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--color-border);
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--color-light);
}

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

/* About Page */
.about-content {
  max-width: 600px;
}

.about-content h1 {
  font-size: 1.25rem;
  font-weight: 500;
  margin-bottom: 1.5rem;
}

.about-content p {
  margin-bottom: 1em;
  color: var(--color-gray);
}

/* Error Page */
.error-page {
  text-align: center;
  padding: 4rem 2rem;
}

.error-page h1 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
}

/* Responsive */
@media (max-width: 768px) {
  .layout {
    flex-direction: column;
  }

  .sidebar {
    position: relative;
    width: 100%;
    min-height: auto;
    padding: 1.5rem;
  }

  .content {
    margin-left: 0;
    padding: 1.5rem;
  }

  .featured-project {
    height: auto;
    min-height: 50vh;
  }

  .nav-projects {
    display: none;
  }

  .nav-category.is-open .nav-projects {
    display: block;
  }
}