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

:root {
  --color-bg: #fafafa;
  --color-bg-alt: #f0f0f0;
  --color-text: #1a1a1a;
  --color-text-muted: #666;
  --color-accent: #2563eb;
  --color-accent-hover: #1d4ed8;
  --color-border: #e5e5e5;
  --color-surface-primary: #c1cadd;
  --font-sans: 'Noto Sans JP', sans-serif;
  --radius: 12px;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.06);
  --transition: 0.2s ease;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.8;
  color: var(--color-text);
  background-color: var(--color-bg);
}

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

ul {
  list-style: none;
}

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Header */
.header {
  position: static;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: var(--color-surface-primary);
}

.nav {
  max-width: 800px;
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-weight: 700;
  font-size: 1.5rem;
  letter-spacing: 0.05em;
}

.nav-list {
  display: flex;
  gap: 32px;
}

.nav-list a {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-text);
  transition: color var(--transition);
}

.nav-list a:hover {
  text-decoration: underline;
}

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

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  transition: var(--transition);}

.btn {
  display: inline-block;
  padding: 14px 32px;
  border-radius: 8px;
  font-weight: 500;
  font-size: 0.95rem;
  transition: background var(--transition), transform var(--transition);
}

.btn-primary {
  background: var(--color-accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--color-accent-hover);
  transform: translateY(-2px);
}

/* Sections */
.section {
  padding-bottom: 40px;
}

.breadcrumb {
  display: flex;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-bottom: 20px;
  list-style: none;
  padding: 0;
}

.breadcrumb li + li::before {
  content: "/";
  margin: 0 8px;
  color: var(--color-text-muted);
}

.breadcrumb-link {
  color: var(--color-accent);
  transition: color var(--transition);
}

.breadcrumb-link:hover {
  text-decoration: underline;
}

.breadcrumb-current {
  font-weight: 500;
}

.introduction {
  padding: 40px 0;
  text-align: center;
}

.introduction-text {
  display: inline-block;
  text-align: left;
  color: var(--color-text-muted);
  font-size: 1rem;
}

.section-title {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 10px;
}

.section-item-wrap {
  padding-bottom: 20px;
}

.section-item {
  display: inline-flex;
  align-items: baseline;
  gap: 12px;
  padding: 0;
}

.section-item:hover {
  text-decoration: underline;
}

.section-label {
  font-size: 1.25rem;
  font-weight: 600;
}

.list-link {
  display: inline-block;
  font-size: 0.9rem;
  color: var(--color-accent);
  transition: color var(--transition);
}

.list-link:hover {
  text-decoration: underline;
}


.date {
  margin-top: 8px;
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* Footer */
.footer {
  padding: 32px 0;
  text-align: center;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  border-top: 1px solid var(--color-border);
}

/* Responsive */
@media (max-width: 768px) {
  .nav-list {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: #fff;
    border-bottom: 1px solid var(--color-border);
    padding: 8px 0;
  }

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

  .nav-list a {
    display: block;
    padding: 12px 24px;
  }

  .nav-toggle {
    display: flex;
  }

  .about-content {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .skills-grid,
  .works-grid {
    grid-template-columns: 1fr;
  }

  .contact-item {
    flex-direction: column;
    align-items: flex-start;
    gap: 4px;
  }

  .blog-grid {
    grid-template-columns: 1fr;
  }

  .blog-post {
    padding: 28px 20px;
  }
}