:root {
  --plum: #6B2D3E;
  --plum-deep: #4A1F2B;
  --mustard: #D4A04A;
  --mustard-light: #E8C07A;
  --paper: #F7F2EC;
  --paper-dark: #EDE6DA;
  --charcoal: #1E1E24;
  --charcoal-light: #3A3A42;
  --shadow: rgba(107, 45, 62, 0.15);
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-pill: 50px;
  --nav-width: 68px;
  --transition: all 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  background: var(--paper);
  color: var(--charcoal);
  line-height: 1.7;
  overflow-x: hidden;
}

a {
  text-decoration: none;
  color: inherit;
  transition: var(--transition);
}

img {
  max-width: 100%;
  display: block;
}

button {
  border: none;
  cursor: pointer;
  font-family: inherit;
  transition: var(--transition);
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Side Navigation */
.side-nav {
  position: fixed;
  left: 20px;
  top: 50%;
  transform: translateY(-50%);
  background: var(--paper);
  border-radius: var(--radius-lg);
  padding: 16px 10px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  box-shadow: 0 8px 32px var(--shadow);
  z-index: 1000;
  border: 1px solid var(--paper-dark);
}

.side-nav a {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  color: var(--charcoal-light);
  position: relative;
}

.side-nav a:hover,
.side-nav a.active {
  background: var(--plum);
  color: var(--paper);
  transform: scale(1.08);
}

.side-nav .nav-tooltip {
  position: absolute;
  left: calc(100% + 12px);
  background: var(--charcoal);
  color: var(--paper);
  padding: 6px 14px;
  border-radius: var(--radius-sm);
  font-size: 13px;
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transform: translateX(-8px);
  transition: var(--transition);
}

.side-nav a:hover .nav-tooltip {
  opacity: 1;
  transform: translateX(0);
}

.side-nav .nav-divider {
  width: 24px;
  height: 1px;
  background: var(--paper-dark);
  margin: 4px auto;
}

.side-nav .nav-user {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--mustard);
  color: var(--paper);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 16px;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: var(--radius-pill);
  font-weight: 500;
  font-size: 15px;
}

.btn-plum {
  background: var(--plum);
  color: var(--paper);
}

.btn-plum:hover {
  background: var(--plum-deep);
  transform: scale(1.05);
  box-shadow: 0 6px 20px var(--shadow);
}

.btn-mustard {
  background: var(--mustard);
  color: var(--paper);
}

.btn-mustard:hover {
  background: var(--mustard-light);
  transform: scale(1.05);
}

.btn-outline {
  background: transparent;
  border: 2px solid var(--plum);
  color: var(--plum);
}

.btn-outline:hover {
  background: var(--plum);
  color: var(--paper);
}

/* Section Titles */
.section-title {
  font-size: 32px;
  font-weight: 700;
  color: var(--plum);
  margin-bottom: 32px;
  position: relative;
  display: inline-block;
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: -6px;
  left: 0;
  width: 60px;
  height: 4px;
  background: var(--mustard);
  border-radius: 2px;
}

/* Cards */
.card {
  background: var(--paper);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: var(--transition);
  box-shadow: 0 4px 16px var(--shadow);
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 32px var(--shadow);
}

/* Footer */
.site-footer {
  background: var(--plum-deep);
  color: var(--paper);
  padding: 60px 0 30px;
  position: relative;
  margin-top: 80px;
}

.site-footer::before {
  content: '';
  position: absolute;
  top: -40px;
  left: 0;
  right: 0;
  height: 40px;
  background: var(--plum-deep);
  border-radius: 50% 50% 0 0;
}

.footer-content {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer-brand h3 {
  font-size: 20px;
  margin-bottom: 12px;
  color: var(--mustard-light);
}

.footer-brand p {
  font-size: 14px;
  line-height: 1.8;
  opacity: 0.85;
}

.footer-links h4 {
  font-size: 16px;
  margin-bottom: 16px;
  color: var(--mustard-light);
}

.footer-links a {
  display: block;
  padding: 6px 0;
  font-size: 14px;
  opacity: 0.75;
}

.footer-links a:hover {
  opacity: 1;
  color: var(--mustard-light);
  padding-left: 8px;
}

.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 20px;
  text-align: center;
  font-size: 13px;
  opacity: 0.65;
}

.footer-bottom a {
  color: var(--mustard-light);
}

/* Responsive */
@media (max-width: 1024px) {
  .side-nav {
    bottom: 20px;
    top: auto;
    left: 50%;
    transform: translateX(-50%);
    flex-direction: row;
    width: auto;
    max-width: calc(100vw - 40px);
    padding: 10px 16px;
  }
  
  .side-nav a {
    width: 40px;
    height: 40px;
  }
  
  .side-nav .nav-tooltip {
    display: none;
  }
  
  .side-nav .nav-divider {
    display: none;
  }
  
  .footer-content {
    grid-template-columns: 1fr;
    text-align: center;
  }
}

@media (max-width: 768px) {
  .section-title {
    font-size: 24px;
  }
}

/* Animations */
@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-float {
  animation: float 6s ease-in-out infinite;
}

.animate-fade-in {
  animation: fadeInUp 0.8s ease-out forwards;
}