:root {
  /* Color Palette */
  --bg-color: #0d1117;
  --text-main: #e6edf3;
  --text-muted: #8b949e;
  --accent: #2f81f7; /* Primary Accent Blue */
  --accent-hover: #58a6ff;
  --card-bg: #161b22;
  --border-color: #30363d;
  
  /* Utilities */
  --transition: all 0.3s ease;
  --header-height: 70px;
}

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

body {
  font-family: 'Inter', 'Noto Sans JP', sans-serif;
  color: var(--text-main);
  background-color: var(--bg-color);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

html {
  scroll-behavior: smooth;
}

/* Container */
.container {
  max-width: 1000px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* Typography */
h1, h2, h3 {
  font-weight: 700;
  line-height: 1.2;
  color: var(--text-main);
}

/* Navigation */
header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: rgba(13, 17, 23, 0.85);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-color);
  z-index: 1000;
}

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: var(--header-height);
}

.logo {
  font-size: 1.25rem;
  font-weight: 700;
  text-decoration: none;
  color: var(--text-main);
  letter-spacing: -0.02em;
  transition: var(--transition);
}

.logo:hover {
  color: var(--accent);
}

.nav-group {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav-links {
  display: flex;
  gap: 1.5rem;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.95rem;
  transition: var(--transition);
}

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

.lang-toggle {
  background: transparent;
  border: 1px solid var(--border-color);
  padding: 0.35rem 0.75rem;
  border-radius: 6px;
  cursor: pointer;
  font-family: inherit;
  font-weight: 600;
  font-size: 0.85rem;
  color: var(--text-muted);
  transition: var(--transition);
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.lang-toggle:hover {
  border-color: var(--text-main);
}

.lang-toggle .active {
  color: var(--accent);
}

/* Sections */
section {
  padding: 8rem 0;
}

.section-title {
  font-size: 2rem;
  margin-bottom: 3.5rem;
  text-align: center;
  position: relative;
  letter-spacing: -0.02em;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -1rem;
  left: 50%;
  transform: translateX(-50%);
  width: 40px;
  height: 3px;
  background-color: var(--accent);
  border-radius: 2px;
}

/* Hero */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding-top: var(--header-height);
  position: relative;
  overflow: hidden;
}

.wave-canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  pointer-events: none;
}

.hero-content {
  max-width: 680px;
  position: relative;
  z-index: 1;
}

.hero-greeting {
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 1rem;
  font-size: 1.125rem;
  display: block;
}

.hero h1 {
  font-size: 3.75rem;
  margin-bottom: 1.5rem;
  letter-spacing: -0.03em;
}

.hero p {
  color: var(--text-muted);
  font-size: 1.125rem;
  margin-bottom: 2.5rem;
  line-height: 1.8;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.875rem 2rem;
  background-color: var(--text-main);
  color: var(--bg-color);
  text-decoration: none;
  border-radius: 6px;
  font-weight: 500;
  transition: var(--transition);
  font-size: 1rem;
}

.btn:hover {
  background-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.2);
}

.hero-actions {
  display: flex;
  gap: 1rem;
  align-items: center;
  flex-wrap: wrap;
}

.btn-outline {
  background-color: transparent;
  color: var(--text-main);
  border: 1px solid var(--border-color);
  display: inline-flex;
  gap: 0.5rem;
}

.btn-outline svg {
  fill: currentColor;
}

.btn-outline:hover {
  background-color: var(--border-color);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
}

/* About Section */
.about {
  background-color: var(--card-bg);
}
.about-content {
  max-width: 700px;
  margin: 0 auto;
  text-align: center;
}

.about-text {
  color: var(--text-muted);
  font-size: 1.125rem;
  margin-bottom: 1.5rem;
  line-height: 1.8;
}

/* Works Section */
.works-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 2.5rem;
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  overflow: hidden;
  transition: var(--transition);
  display: flex;
  flex-direction: column;
  box-shadow: 0 1px 3px rgba(0,0,0,0.05);
}

.card:hover {
  box-shadow: 0 20px 25px -5px rgba(0,0,0,0.05), 0 10px 10px -5px rgba(0,0,0,0.02);
  transform: translateY(-4px);
  border-color: transparent;
}

.card-img {
  width: 100%;
  height: 220px;
  object-fit: cover;
  object-position: top;
  background-color: var(--bg-color);
  border-bottom: 1px solid var(--border-color);
}

.card-body {
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.card-title {
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
}

.card-desc {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 1.75rem;
  flex-grow: 1;
  line-height: 1.6;
}

.card-links {
  display: flex;
  gap: 1.25rem;
}

.card-link {
  font-size: 0.9rem;
  color: var(--text-main);
  text-decoration: none;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 0.35rem;
  transition: var(--transition);
}

.card-link svg {
  width: 16px;
  height: 16px;
  fill: currentColor;
}

.card-link:hover {
  color: var(--accent);
}

/* Footer */
footer {
  text-align: center;
  padding: 4rem 0;
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* Responsive adjustments */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 2.5rem;
  }
  section {
    padding: 5rem 0;
  }
  .nav-group {
    gap: 1rem;
  }
  .nav-links {
    display: none;
  }
  .container {
    padding: 0 1.5rem;
  }
}