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

:root {
  --color-bg: #ffffff;
  --color-text: #1a1a1a;
  --color-muted: #6b6b6b;
  --color-border: #e5e5e5;
  --color-accent: #c8a820;
  --font-ja: 'Noto Serif JP', serif;
  --font-en: 'EB Garamond', Georgia, serif;
  --max-width: 680px;
}

html[lang="ja"] { font-family: var(--font-ja); }
html[lang="en"] { font-family: var(--font-en); }

html[lang="ja"] .en { display: none; }
html[lang="en"] .ja { display: none; }

html {
  font-size: 18px;
  scroll-behavior: smooth;
}

body {
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.8;
  padding: 4rem 1.5rem 6rem;
}

main {
  max-width: var(--max-width);
  margin: 0 auto;
}

/* language toggle */
nav {
  position: fixed;
  top: 1.5rem;
  right: 1.5rem;
}

#lang-toggle {
  background: none;
  border: 1px solid var(--color-border);
  font-family: inherit;
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  padding: 0.3rem 0.65rem;
  cursor: pointer;
  color: var(--color-muted);
  transition: color 0.15s, border-color 0.15s;
}

#lang-toggle:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
}

/* header */
header {
  margin-bottom: 4rem;
  padding-bottom: 3rem;
  border-bottom: 1px solid var(--color-border);
}

h1 {
  font-size: 2rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  margin-bottom: 0.5rem;
}

.tagline {
  color: var(--color-muted);
  font-size: 1rem;
}

html[lang="en"] .tagline { font-style: italic; }

/* sections */
section {
  margin-bottom: 4rem;
}

h2 {
  font-size: 0.72rem;
  font-weight: 400;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 1.5rem;
}

html[lang="ja"] h2 {
  letter-spacing: 0.2em;
}

#about p {
  font-size: 1.05rem;
  max-width: 520px;
}

/* skills */
.skill-groups {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

h3 {
  font-size: 0.68rem;
  font-weight: 400;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-muted);
  margin-bottom: 0.75rem;
}

html[lang="ja"] h3 {
  letter-spacing: 0.15em;
}

ul {
  list-style: none;
}

.skill-group li {
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--color-border);
}

.skill-group li:first-child {
  border-top: 1px solid var(--color-border);
}

.skill-name {
  display: block;
  font-size: 0.95rem;
  line-height: 1.6;
}

.skill-note {
  display: block;
  font-size: 0.78rem;
  color: var(--color-muted);
  line-height: 1.5;
}

/* works */
.works-list li {
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--color-border);
  font-size: 1rem;
}

.works-list li:first-child {
  border-top: 1px solid var(--color-border);
}

/* links */
a {
  color: inherit;
  text-decoration: underline;
  text-underline-offset: 3px;
}

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

@media (max-width: 520px) {
  html { font-size: 16px; }

  .skill-groups {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }
}