:root {
  --primary-color: #2c3e50;
  --secondary-color: #3498db;
  --accent-color: #e74c3c;
  --text-color: #34495e;
  --light-bg: #f8f9fa;
  --border-radius: 12px;
  --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

body {
  font-family: 'Segoe UI', system-ui, sans-serif;
  line-height: 1.6;
  color: var(--text-color);
  background-color: var(--light-bg);
}

.about-header {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: white;
  padding: 2rem 1.5rem;
  box-shadow: var(--shadow);
  margin-bottom: 2rem;
}

.brand-container {
  display: flex;
  align-items: center;
  max-width: 1200px;
  margin: 0 auto;
}

.logo {
  width: 60px;
  height: 60px;
  margin-right: 1.5rem;
  filter: drop-shadow(0 2px 4px rgba(0,0,0,0.2));
}

.brand-info h1 {
  font-size: 2.2rem;
  margin: 0;
}

.brand-info h1 a {
  color: inherit;
  text-decoration: none;
}

.brand-info {
  position: relative;
  flex-grow: 1;
}

.thanks {
  position: absolute;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  font-size: 12px;
  color: #ffffff;
  white-space: nowrap;
}

.slogan {
  font-size: 1.1rem;
  opacity: 0.9;
  margin: 0.5rem 0 0;
}

.about-nav {
  margin-top: 1.5rem;

  max-width: 1200px;
  margin: 0 auto;
}

.about-nav ul {
  display: flex;
  gap: 2rem;
  list-style: none;
  padding: 0;
  margin: 0;
}

.nav-link {
  color: rgba(255,255,255,0.9);
  text-decoration: none;
  padding: 0.5rem 1rem;
  border-radius: 6px;
  transition: all 0.3s ease;
}

.nav-link:hover,
.nav-link.active {
  background: rgba(255,255,255,0.1);
  color: white;
}

.about-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem 4rem;
}

.feature-card,
.update-card,
.contact-card {
  background: white;
  border-radius: var(--border-radius);
  padding: 2rem;
  margin-bottom: 2rem;
  box-shadow: var(--shadow);
  transition: transform 0.3s ease;
}

.feature-card:hover {
  transform: translateY(-5px);
}

.section-title {
  display: flex;
  align-items: center;
  gap: 1rem;
  font-size: 1.5rem;
  color: var(--primary-color);
  margin: 0 0 2rem;
  padding-right: 120px;
}

.describe {
  position: static;
  vertical-align: baseline;
  transform: none;
  margin-left: 1.5em;
  display: inline-flex;
  align-items: center;
  font-size: 0.8em; 
}

.icon {
  fill: currentColor;
}

.download-section {
  display: flex;
  gap: 1.5rem;
  align-items: center;
}

.download-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.8rem;
  padding: 0.8rem 1.5rem;
  background: var(--secondary-color);
  color: white;
  border-radius: 8px;
  text-decoration: none;
  transition: all 0.3s ease;
}

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

.guide-link {
  color: var(--secondary-color);
  text-decoration: none;
  font-weight: 500;
}

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

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
}

.feature-item {
  padding: 1.5rem;
  background: var(--light-bg);
  border-radius: 8px;
}

.feature-item h3 {
  color: var(--secondary-color);
  margin: 0 0 1rem;
}

.feature-item ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.feature-item li {
  padding: 0.5rem 0;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.feature-item li::before {
  content: "✓";
  color: var(--secondary-color);
}

.update-list {
  display: grid;
  gap: 1.5rem;
}

.update-item {
  padding: 1.5rem;
  border-left: 4px solid var(--secondary-color);
  background: var(--light-bg);
  position: relative;
}

.update-badge {
  position: absolute;
  top: -10px;
  right: -10px;
  background: var(--accent-color);
  color: white;
  padding: 0.3rem 0.8rem;
  border-radius: 20px;
  font-size: 0.9rem;
  font-weight: bold;
}

.contact-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
}

.contact-method {
  display: grid;
  gap: 1.5rem;
}

.contact-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem;
  background: var(--light-bg);
  border-radius: 8px;
}

.contact-item a {
  color: var(--text-color);
  text-decoration: none;
}

.contact-item a:hover {
  color: var(--secondary-color);
}

.partner-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 1rem;
}

.partner-item {
  padding: 1rem;
  background: var(--light-bg);
  border-radius: 8px;
  text-align: center;
  text-decoration: none;
  color: var(--text-color);
  transition: all 0.3s ease;
}

.partner-item:hover {
  background: var(--secondary-color);
  color: white;
}

@media (max-width: 768px) {
  .brand-container {
    flex-direction: column;
    text-align: center;
  }
  
  .logo {
    margin: 0 0 1rem;
  }
  
  .about-nav ul {
    flex-wrap: wrap;
    justify-content: center;
    gap: 1rem;
  }
  
  .contact-content {
    grid-template-columns: 1fr;
  }
  
  .feature-grid {
    grid-template-columns: 1fr;
  }
}