:root {
  --bg-color: #0a0a0a;
  --text-color: #ffffff;
  --accent-color: #00ffaa;
  --header-bg: rgba(10, 10, 10, 0.8);
  --overlay-bg: rgba(0, 0, 0, 0.5);
  --section-padding: 100px 20px;
  --transition-speed: 0.3s;
}

body {
  background-color: var(--bg-color);
  color: var(--text-color);
  font-family: 'Inter', 'Helvetica Neue', 'Noto Sans JP', sans-serif;
  line-height: 1.6;
  overflow-x: hidden;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
}

h2 {
  font-size: 2.5rem;
  margin-bottom: 2rem;
  text-align: center;
  text-transform: uppercase;
  letter-spacing: 2px;
}

h2 span {
  color: var(--accent-color);
}

/* Layout Utilities */
.container {
  max-width: 1200px;
  margin: 0 auto;
  width: 100%;
}

section {
  padding: var(--section-padding);
}

/* Header */
header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 80px;
  background-color: var(--header-bg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 40px;
  transition: all var(--transition-speed) ease;
}

.logo img {
  height: 40px;
  width: auto;
}

/* Navigation */
.nav-links {
  display: flex;
  gap: 30px;
}

.nav-links li a {
  font-weight: 500;
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  position: relative;
  padding: 5px 0;
  transition: color var(--transition-speed);
}

.nav-links li a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--accent-color);
  transition: width var(--transition-speed) ease;
}

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

.nav-links li a:hover::after {
  width: 100%;
}

/* Hamburger Menu */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 6px;
  z-index: 1001;
}

.hamburger span {
  display: block;
  width: 30px;
  height: 2px;
  background-color: var(--text-color);
  transition: all var(--transition-speed) ease;
}

.hamburger.active span:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
  background-color: var(--accent-color);
}

.hamburger.active span:nth-child(2) {
  opacity: 0;
}

.hamburger.active span:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
  background-color: var(--accent-color);
}

/* Footer */
footer {
  padding: 60px 20px;
  background-color: #050505;
  text-align: center;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
}

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

.social-links a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background-color: rgba(255, 255, 255, 0.05);
  transition: all var(--transition-speed);
}

.social-links a:hover {
  background-color: var(--accent-color);
  color: #000;
  transform: translateY(-3px);
}

.copyright {
  font-size: 0.8rem;
  color: rgba(255, 255, 255, 0.5);
  letter-spacing: 1px;
}

/* Animations */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.8s ease, transform 0.8s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 12px 30px;
  background-color: transparent;
  color: var(--text-color);
  border: 1px solid var(--accent-color);
  border-radius: 30px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1px;
  transition: all var(--transition-speed);
  position: relative;
  overflow: hidden;
  z-index: 1;
}

.btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 0%;
  height: 100%;
  background-color: var(--accent-color);
  transition: width var(--transition-speed) ease;
  z-index: -1;
}

.btn:hover {
  color: var(--bg-color);
}

.btn:hover::before {
  width: 100%;
}

/* Responsive */
@media (max-width: 768px) {
  header {
    padding: 0 20px;
  }

  .hamburger {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: 0;
    right: -100%;
    width: 100%;
    height: 100vh;
    background-color: var(--bg-color);
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 40px;
    transition: right 0.4s ease;
  }

  .nav-links.active {
    right: 0;
  }

  .nav-links li a {
    font-size: 1.5rem;
  }
}