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

body {
  font-family:
    system-ui,
    -apple-system,
    "Segoe UI",
    Roboto,
    "Helvetica Neue",
    Helvetica,
    sans-serif;
  background: #0a192f;
  color: #eef2ff;
  line-height: 1.5;
  scroll-behavior: smooth;
}

/* Background overlay with image + blue semi-transparent layer */
.bg-wrapper {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -2;
  overflow: hidden;
}

.bg-image {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
}

.blue-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(10, 35, 55, 0.75);
  background: linear-gradient(
    125deg,
    rgba(6, 27, 49, 0.85) 0%,
    rgba(10, 45, 75, 0.75) 100%
  );
  backdrop-filter: blur(1px);
}

/* main content layer */
.main-content {
  position: relative;
  z-index: 2;
  max-width: 1280px;
  margin: 0 auto;
  padding: 1.5rem 2rem 0;
}

/* Navigation */
.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  padding: 1rem 0 1.5rem 0;
  border-bottom: 1px solid rgba(100, 150, 200, 0.3);
  margin-bottom: 2rem;
}

.logo {
  font-size: 1.8rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, #ffffff, #8ab4f8);
  background-clip: text;
  -webkit-background-clip: text;
  color: transparent;
}

.nav-links {
  display: flex;
  gap: 2rem;
  list-style: none;
  flex-wrap: wrap;
}

.nav-links a {
  color: #eef2ff;
  text-decoration: none;
  font-weight: 500;
  font-size: 1rem;
  transition: color 0.2s ease;
  letter-spacing: 0.3px;
}

.nav-links a:hover {
  color: #79d7ff;
  border-bottom: 1px solid #79d7ff;
  padding-bottom: 4px;
}

/* common sections */
section {
  scroll-margin-top: 5rem;
  margin-bottom: 6rem;
}

/* banner */
.banner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 3rem;
  background: rgba(15, 35, 55, 0.4);
  backdrop-filter: blur(4px);
  border-radius: 2rem;
  padding: 2rem 2rem;
  border: 1px solid rgba(80, 140, 200, 0.3);
}

.banner-text {
  flex: 1.2;
}

.banner-text h1 {
  font-size: 3rem;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 1rem;
  background: linear-gradient(to right, #ffffff, #b3e4ff);
  background-clip: text;
  -webkit-background-clip: text;
  color: transparent;
}

.banner-text p {
  font-size: 1.2rem;
  color: #cfdfef;
  max-width: 90%;
}

.banner-image {
  flex: 0.8;
  display: flex;
  justify-content: center;
  transition:
    transform 0.25s ease,
    box-shadow 0.3s;
  cursor: pointer;
}

.banner-image img {
  width: 220px;
  height: auto;
  border-radius: 32px;
  box-shadow: 0 20px 35px -12px rgba(0, 0, 0, 0.5);
  border: 2px solid rgba(255, 255, 240, 0.2);
  transition: all 0.3s cubic-bezier(0.2, 0.9, 0.4, 1.1);
}

/* hover effect for banner screenshot */
.banner-image:hover img {
  transform: scale(1.03) translateY(-8px);
  box-shadow: 0 30px 40px -12px rgba(0, 0, 0, 0.6);
  border-color: rgba(100, 180, 250, 0.7);
}

/* intro & features layout (交错布局) */
.split-layout {
  display: flex;
  align-items: center;
  gap: 3rem;
  margin-bottom: 4rem;
  flex-wrap: wrap;
}

.split-reverse {
  flex-direction: row-reverse;
}

.text-side {
  flex: 1;
}

.image-side {
  flex: 0.3;
  display: flex;
  justify-content: center;
}

.image-side img {
  max-width: 100%;
  border-radius: 28px;
  box-shadow: 0 18px 30px -10px rgba(0, 0, 0, 0.4);
  transition: transform 0.2s ease;
  width: 100%;
  object-fit: cover;
  border: 1px solid rgba(90, 160, 220, 0.3);
}

.image-side img:hover {
  transform: scale(1.01);
}

.section-title {
  font-size: 2.2rem;
  font-weight: 700;
  margin-bottom: 2rem;
  letter-spacing: -0.3px;
  border-left: 5px solid #3b82f6;
  padding-left: 1rem;
}

.text-side h3 {
  font-size: 1.8rem;
  font-weight: 600;
  margin-bottom: 1rem;
  color: #c6e9ff;
}

.text-side p {
  font-size: 1.05rem;
  color: #dce7f5;
  margin-bottom: 1rem;
}

/* features grid (cards) */
.features-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 2rem;
  justify-content: center;
  margin-top: 1rem;
}

.feature-card {
  background: rgba(12, 35, 55, 0.7);
  backdrop-filter: blur(8px);
  border-radius: 1.5rem;
  padding: 1.8rem;
  flex: 1 1 260px;
  border: 1px solid rgba(70, 130, 200, 0.4);
  transition: all 0.25s;
}

.feature-card:hover {
  background: rgba(20, 55, 85, 0.8);
  transform: translateY(-5px);
  border-color: #3b82f6;
}

.feature-card h4 {
  font-size: 1.5rem;
  margin-bottom: 0.75rem;
  color: white;
}

.feature-card p {
  font-size: 0.95rem;
  color: #cbddee;
}

/* screenshot section */
.screenshot-show {
  background: rgba(6, 25, 45, 0.5);
  border-radius: 2rem;
  padding: 2rem;
  text-align: center;
  backdrop-filter: blur(3px);
}

.screenshot-gallery {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 2rem;
  margin-top: 2rem;
}

.screenshot-gallery img {
  width: 210px;
  border-radius: 28px;
  box-shadow: 0 20px 28px -12px black;
  border: 1px solid #2c5a7a;
  transition: transform 0.2s;
}

.screenshot-gallery img:hover {
  transform: scale(1.02);
}

/* contact footer */
.footer {
  margin-top: 4rem;
  padding: 2rem 0 2.5rem;
  border-top: 1px solid rgba(100, 150, 200, 0.3);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.contact-info {
  font-size: 1rem;
}

.contact-info a {
  color: #aad0ff;
  text-decoration: none;
  border-bottom: 1px dotted;
}

.contact-info a:hover {
  color: white;
}

.copyright {
  font-size: 0.85rem;
  opacity: 0.8;
}

@media (max-width: 780px) {
  .main-content {
    padding: 1rem 1.2rem;
  }
  .navbar {
    flex-direction: column;
    gap: 1rem;
    align-items: center;
  }
  .nav-links {
    gap: 1.2rem;
    justify-content: center;
  }
  .banner-text h1 {
    font-size: 2.2rem;
  }
  .banner-text p {
    max-width: 100%;
  }
  .split-layout,
  .split-reverse {
    flex-direction: column;
  }
  .section-title {
    font-size: 1.8rem;
  }
  .text-side h3 {
    font-size: 1.5rem;
  }
  .banner-image img {
    width: 180px;
  }
  .screenshot-gallery img {
    width: 150px;
  }
  .footer {
    flex-direction: column;
    text-align: center;
  }
}

button,
a {
  cursor: pointer;
}
.highlight-blue {
  color: #7bc5ff;
}