:root {
  --bg-color-light: #f8f8f8;
  --bg-color-dark: #0d0d0d;
  --text-color-light: #000000;
  --text-color-dark: #ffffff;
  --glass-bg-light: rgba(255, 255, 255, 0.6);
  --glass-bg-dark: rgba(0, 0, 0, 0.4);
  --btn-bg: rgba(255, 255, 255, 0.7);
  --btn-text: #000;
  --btn-hover: rgba(255, 255, 255, 0.9);
  --transition-fast: 0.3s ease;
}

html[data-theme="light"] {
  --bg-color: var(--bg-color-light);
  --text-color: var(--text-color-light);
  --glass-bg: var(--glass-bg-light);
}

html[data-theme="dark"] {
  --bg-color: var(--bg-color-dark);
  --text-color: var(--text-color-dark);
  --glass-bg: var(--glass-bg-dark);
}

body {
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-color);
  color: var(--text-color);
  transition: background var(--transition-fast), color var(--transition-fast);
}

.site-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 24px 48px;
  font-size: 18px;
  position: sticky;
  top: 0;
  backdrop-filter: blur(16px);
  background: var(--glass-bg);
  border-bottom: 1px solid rgba(0,0,0,0.05);
  z-index: 10;
}

.logo {
  font-weight: 600;
  font-size: 20px;
}

.controls button {
  background: none;
  border: none;
  font-size: 20px;
  margin-left: 12px;
  cursor: pointer;
  color: var(--text-color);
  transition: transform var(--transition-fast);
}

.controls button:hover {
  transform: scale(1.1);
}

.container {
  max-width: 860px;
  margin: 0 auto;
  padding: 60px 20px;
}

section {
  margin-bottom: 80px;
  text-align: center;
}

.title {
  font-size: 48px;
  font-weight: 700;
  margin-bottom: 20px;
}

.subtitle {
  font-size: 20px;
  opacity: 0.8;
  margin-bottom: 40px;
}

h2 {
  font-size: 28px;
  margin-bottom: 10px;
}

p {
  font-size: 18px;
  line-height: 1.6;
  margin-bottom: 30px;
}

.btn {
  display: inline-block;
  padding: 12px 28px;
  font-size: 16px;
  border-radius: 12px;
  background: var(--btn-bg);
  color: var(--btn-text);
  text-decoration: none;
  transition: background var(--transition-fast), transform var(--transition-fast);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

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


.contact-button {
  background: white;
  color: #000;
  padding: 12px 24px;
  border-radius: 12px;
  border: 1px solid #ccc;
  font-size: 16px;
  text-decoration: none;
  display: inline-block;
  transition: all 0.3s ease;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.contact-button:hover {
  background: linear-gradient(135deg, #6e8efb, #a777e3);
  color: white;
  border: none;
  transform: scale(1.05);
}


footer {
  text-align: center;
  font-size: 14px;
  padding: 40px 20px;
  margin-top: 80px;
  background: linear-gradient(135deg, #e0e0e0, #f5f5f5);
  border-top: 1px solid rgba(0, 0, 0, 0.08);
  color: #333;
  box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.04);
  border-radius: 16px 16px 0 0;
}


.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: all 0.8s ease-out;
}

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

.slide-up {
  transition-delay: 0.2s;
}

.delay {
  transition-delay: 0.6s;
}

.btn:hover {
  transform: scale(1.05);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
}