:root {
  --primary-color: #8cc9ff;
  --secondary-color: #ffd580;
  --accent-color: #9b6bff;
  --text-color: rgba(255, 255, 255, 0.92);
  --muted-text: rgba(255, 255, 255, 0.65);
  --card-bg: rgba(17, 26, 40, 0.55);
  --glass-border: rgba(255, 255, 255, 0.18);
  --blur-radius: 22px;
  --background-image: url('https://images.unsplash.com/photo-1519681393784-d120267933ba?auto=format&fit=crop&w=1974&q=80');
  --nav-height: 4rem;
  font-size: 16px;
  font-family: 'Poppins', 'Segoe UI', sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--text-color);
  background: var(--background-image),
              radial-gradient(circle at 20% 20%, rgba(156, 103, 255, 0.35), transparent 55%),
              radial-gradient(circle at 80% 10%, rgba(247, 175, 130, 0.25), transparent 45%),
              #0d1a2b;
  background-size: cover;
  background-position: center;
  background-attachment: fixed;
  line-height: 1.6;
  position: relative;
  overflow-x: hidden;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background: var(--background-image) center/cover no-repeat;
  filter: saturate(120%) brightness(80%);
  opacity: 0.35;
  z-index: -2;
}

body::after {
  content: '';
  position: fixed;
  inset: 0;
  background: linear-gradient(180deg, rgba(13, 26, 43, 0.09), rgba(13, 26, 43, 0.15));
  z-index: -1;
}

a {
  color: inherit;
  text-decoration: none;
}

header {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  justify-content: center;
  padding: 0;
  background: transparent;
}

.navbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin: 0 auto;
  width: 80%;          /* 改为全宽 */
  max-width: none;      /* 取消最大宽限制 */
  padding: 0rem 1rem;
  min-height: var(--nav-height);
  background: rgba(61, 68, 78, 0.48);
  backdrop-filter: blur(var(--blur-radius));
  border-radius: 0 0 24px 24px;
  box-shadow: 0 10px 30px rgba(6, 12, 21, 0.35);
}

.navbar__brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--secondary-color);
  text-shadow: 0 0 12px rgba(255, 213, 128, 0.5);
  font-size: 1.4rem;
  transition: text-shadow 0.3s ease, transform 0.3s ease;
}

.navbar__brand:hover {
  transform: scale(1.05);
  text-shadow: 0 0 18px rgba(255, 213, 128, 0.8);
}

.navbar__brand span {
  font-size: 0.75rem;
  color: var(--muted-text);
}

.navbar__links {
  display: flex;
  gap: 1.25rem;
  align-items: center;
}

.navbar__links a {
  padding: 0.45rem 0.9rem;
  border-radius: 999px;
  position: relative;
  transition: color 0.3s ease, background 0.3s ease, transform 0.3s ease;
  font-weight: 500;
  letter-spacing: 0.03em;
}

.navbar__links a::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: linear-gradient(135deg, rgba(156, 103, 255, 0.12), rgba(255, 213, 128, 0.12));
  opacity: 0;
  transition: opacity 0.3s ease;
  z-index: -1;
}

.navbar__links a:hover,
.navbar__links a:focus {
  transform: translateY(-2px);
}

.navbar__links a:hover::after,
.navbar__links a:focus::after,
.navbar__links a.is-active::after {
  opacity: 1;
}

.navbar__links a.is-active {
  color: var(--primary-color);
}

.navbar__toggle {
  display: none;
  border: none;
  background: rgba(255, 255, 255, 0.08);
  padding: 0.5rem 0.75rem;
  border-radius: 8px;
  color: var(--text-color);
}

main {
  width: 60%;
  max-width: 2000px;
  margin: 0 auto;
  padding: 3rem 2rem 5rem;
}

.glass-card {
  background: var(--card-bg);
  border: 0 solid var(--glass-border);
  border-radius: 32px;
  padding: 2rem;
  backdrop-filter: blur(var(--blur-radius));
  box-shadow: 0 20px 45px rgba(6, 12, 21, 0.35);
}

.section-title {
  font-size: clamp(2rem, 4vw, 3rem);
  margin-bottom: 1rem;
  font-weight: 600;
}

.section-subtitle {
  color: var(--muted-text);
  margin-bottom: 2.5rem;
  max-width: 640px;
}

.grid {
  display: grid;
  gap: 1.75rem;
}

.grid--two {
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.35rem 0.75rem;
  border-radius: 999px;
  background: rgba(156, 103, 255, 0.22);
  color: var(--secondary-color);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.6rem;
  height: 48px;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, 0.2);
  cursor: pointer;
  font-weight: 600;
  color: #fff;
  text-decoration: none;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
  background: linear-gradient(135deg, rgba(22, 18, 63, 0.5) 0%, rgba(84, 94, 28, 0.5) 100%);
  backdrop-filter: blur(10px);
}

.button:hover {
  transform: translateY(-3px);
  box-shadow: 0 15px 35px rgba(9, 15, 28, 0.35);
}

.button:active {
  transform: translateY(0);
}

/* Snow overlay */
.snow {
  position: fixed;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
}

.snow-back {
  z-index: 0;
}

.snow-front {
  z-index: 1000;
}

.snow__flake {
  position: absolute;
  top: -10vh;
  left: var(--x);
  width: var(--size);
  height: var(--size);
  border-radius: 50%;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.9), rgba(255, 255, 255, 0.7) 80%);
  filter: blur(calc(var(--size) / 6));
  opacity: var(--opacity);
  animation:
    snow-fall var(--speed) linear var(--delay) infinite,
    snow-sway calc(var(--speed) * 0.6) ease-in-out var(--delay) infinite alternate;
}

.snow-back .snow__flake {
  filter: blur(2px);
  opacity: 0.35;
}

.snow-front .snow__flake {
  filter: blur(0.5px);
  opacity: 0.9;
}

@keyframes snow-fall {
  to {
    transform: translateY(110vh);
  }
}

@keyframes snow-sway {
  from {
    margin-left: 0;
  }

  to {
    margin-left: var(--drift);
  }
}

@media (prefers-reduced-motion: reduce) {
  .snow__flake {
    animation: none;
  }

  .snow {
    display: none;
  }
}

footer {
  max-width: 1200px;
  margin: 0 auto 3rem;
  padding: 1.5rem 2rem;
  color: var(--muted-text);
  text-align: center;
}

/* Utilities */
.fade-in {
  animation: fadeUp 1s ease forwards;
  opacity: 0;
  transform: translateY(24px);
}

.fade-in:nth-child(2) {
  animation-delay: 0.15s;
}

.fade-in:nth-child(3) {
  animation-delay: 0.3s;
}

.fade-in:nth-child(4) {
  animation-delay: 0.45s;
}

@keyframes fadeUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 900px) {
  .navbar {
    padding: 1rem 1.25rem;
    width: 100%;
    border-radius: 0;
  }

  .navbar__links {
    position: fixed;
    top: 80px;
    right: 1.5rem;
    flex-direction: column;
    gap: 0.75rem;
    background: rgba(12, 23, 38, 0.92);
    padding: 1.5rem;
    border-radius: 20px;
    border: 1px solid rgba(255, 255, 255, 0.12);
    box-shadow: 0 20px 45px rgba(9, 15, 28, 0.55);
    transform: translateY(-20px);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
  }

  .navbar__links.is-open {
    opacity: 1;
    pointer-events: auto;
  }

  .navbar__toggle {
    display: inline-flex;
  }
}

@media (max-width: 600px) {
  main {
    width: 90%;
    padding: 2rem 1rem 3.5rem;
  }
  
  .navbar {
    padding: 1rem 0.75rem;
    width: 100%;
    border-radius: 0;
  }

  .navbar__links {
    right: 1rem;
    top: 75px;
  }
}