:root {
  --primary: #E53935;
  --secondary: #FF5A4F;
  --background: #F5F7FA;
  --card-bg: #FFFFFF;
  --text-main: #333333;
  --border: #E0E0E0;
  --header-offset: 122px;
}

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

body {
  font-family: 'Be Vietnam Pro', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background-color: var(--background);
  color: var(--text-main);
  line-height: 1.6;
  padding-top: var(--header-offset);
}

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

ul {
  list-style: none;
}

/* ===== HEADER ===== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background-color: #FFFFFF;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.header-top {
  background-color: #E53935;
  width: 100%;
}

.header-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 20px;
  min-height: 68px;
}

.logo {
  font-size: 1.8rem;
  font-weight: 800;
  letter-spacing: 1px;
  color: #FFFFFF;
  display: inline-block;
  line-height: 1.2;
  text-transform: lowercase;
}

.logo:hover {
  color: rgba(255, 255, 255, 0.9);
}

.desktop-nav-buttons {
  display: flex;
  align-items: center;
  gap: 10px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 20px;
  border-radius: 24px;
  font-weight: 600;
  font-size: 0.9rem;
  line-height: 1.2;
  transition: all 0.3s ease;
  cursor: pointer;
  border: 2px solid transparent;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  min-height: 40px;
}

.btn-register {
  background: linear-gradient(180deg, #FF5A4F 0%, #E53935 100%);
  color: #FFFFFF;
  border-color: #FFFFFF;
}

.btn-register:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(229, 57, 53, 0.4);
}

.btn-login {
  background: #FFFFFF;
  color: #E53935;
  border: 2px solid #E53935;
}

.btn-login:hover {
  background: #E53935;
  color: #FFFFFF;
  transform: translateY(-2px);
}

.btn-download {
  background: #333333;
  color: #FFFFFF;
  border-color: #333333;
}

.btn-download:hover {
  background: #000000;
  transform: translateY(-2px);
}

/* ===== MAIN NAV ===== */
.main-nav {
  background-color: #FFFFFF;
  width: 100%;
  display: flex;
  min-height: 52px;
  border-bottom: 1px solid var(--border);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  flex-direction: row;
  justify-content: center;
  align-items: center;
  padding: 8px 20px;
  gap: 6px;
  width: 100%;
}

.nav-link {
  color: #333333;
  font-weight: 500;
  font-size: 0.9rem;
  padding: 6px 12px;
  border-radius: 4px;
  transition: all 0.3s ease;
  white-space: nowrap;
  display: inline-block;
}

.nav-link:hover {
  color: #E53935;
  background-color: rgba(229, 57, 53, 0.05);
}

.nav-link.active {
  color: #E53935;
  font-weight: 600;
}

/* ===== MOBILE NAV BUTTONS ===== */
.mobile-nav-buttons {
  display: none;
}

/* ===== HAMBURGER MENU ===== */
.hamburger-menu {
  display: none;
}

.mobile-menu-overlay {
  display: none;
}

/* ===== FOOTER ===== */
.site-footer {
  background-color: #E53935;
  color: #FFFFFF;
  padding: 40px 0 0;
  margin-top: 40px;
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 40px;
  padding: 0 20px;
}

.footer-logo {
  font-size: 1.8rem;
  font-weight: 800;
  color: #FFFFFF;
  text-transform: lowercase;
  display: inline-block;
  margin-bottom: 16px;
}

.footer-description {
  color: rgba(255, 255, 255, 0.85);
  font-size: 0.9rem;
  max-width: 320px;
  line-height: 1.6;
}

.footer-heading {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 16px;
  color: #FFFFFF;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.footer-nav li {
  margin-bottom: 10px;
}

.footer-nav a {
  color: rgba(255, 255, 255, 0.85);
  font-size: 0.9rem;
  transition: all 0.3s ease;
  display: inline-block;
  padding: 2px 0;
}

.footer-nav a:hover {
  color: #FFFFFF;
  transform: translateX(4px);
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.2);
  padding: 20px;
  text-align: center;
  margin-top: 40px;
  background-color: rgba(0, 0, 0, 0.2);
}

.footer-bottom p {
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.8);
}

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
  :root {
    --header-offset: 110px;
  }

  .header-container {
    width: 100%;
    max-width: none;
    padding-left: 15px;
    padding-right: 15px;
    min-height: 60px;
  }

  .nav-container {
    width: 100%;
    max-width: none;
    padding-left: 15px;
    padding-right: 15px;
  }

  .site-header {
    background-color: #FFFFFF;
  }

  .header-top {
    padding: 0;
  }

  .header-container {
    display: flex;
    align-items: center;
    justify-content: center;
    padding-top: 0;
    padding-bottom: 0;
  }

  .logo {
    font-size: 1.5rem;
    padding: 8px 0;
    display: block;
    order: 1;
    margin: 0 auto;
    text-align: center;
    flex: 0 0 auto;
  }

  .desktop-nav-buttons {
    display: none;
  }

  .main-nav {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 280px;
    height: 100vh;
    background-color: #FFFFFF;
    box-shadow: 2px 0 12px rgba(0, 0, 0, 0.15);
    padding: 80px 0 40px;
    overflow-y: auto;
    transform: translateX(-100%);
    transition: transform 0.3s ease;
    z-index: 1002;
    border-bottom: none;
  }

  .main-nav.active {
    display: flex;
    transform: translateX(0);
  }

  .nav-container {
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    align-items: stretch;
    gap: 4px;
    padding: 20px 20px;
  }

  .nav-link {
    display: block;
    padding: 14px 16px;
    font-size: 0.95rem;
    border-bottom: 1px solid #f0f0f0;
    border-radius: 0;
    color: #333333;
  }

  .nav-link:hover {
    background-color: rgba(229, 57, 53, 0.05);
    color: #E53935;
  }

  .mobile-nav-buttons {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 8px;
    padding: 8px 15px;
    background-color: #FFFFFF;
    border-bottom: 1px solid #E0E0E0;
    min-height: 48px;
  }

  .mobile-nav-buttons .btn {
    flex: 1;
    max-width: 130px;
    padding: 8px 10px;
    font-size: 0.8rem;
    min-height: 36px;
  }

  .hamburger-menu {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 5px;
    width: 44px;
    height: 44px;
    background: transparent;
    border: none;
    cursor: pointer;
    position: absolute;
    left: 10px;
    top: 8px;
    z-index: 1003;
    padding: 8px;
  }

  .bar {
    display: block;
    width: 22px;
    height: 2px;
    background-color: #E53935;
    border-radius: 2px;
    transition: all 0.3s ease;
  }

  .hamburger-menu.active .bar:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }

  .hamburger-menu.active .bar:nth-child(2) {
    opacity: 0;
  }

  .hamburger-menu.active .bar:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }

  .mobile-menu-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.6);
    z-index: 1001;
  }

  .mobile-menu-overlay.active {
    display: block;
  }

  /* Footer mobile */
  .footer-container {
    grid-template-columns: 1fr;
    gap: 30px;
    padding: 0 20px;
  }

  .footer-description {
    max-width: 100%;
  }

  /* Content protection */
  .page-content img {
    max-width: 100% !important;
    height: auto !important;
    display: block;
  }

  .page-content {
    overflow-x: hidden;
    max-width: 100%;
  }

  body {
    overflow-x: hidden;
  }
}
/* 移动端内容区防溢出（系统追加，请勿删除） */
@media (max-width: 768px) {
  .page-content img {
    max-width: 100% !important;
    height: auto !important;
    display: block;
  }
  .page-content {
    overflow-x: hidden;
    max-width: 100%;
  }
  body {
    overflow-x: hidden;
  }
}
/* 内容保护（系统追加，请勿删除） */
body {
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}
input, textarea, select, [contenteditable="true"] {
  -webkit-user-select: text;
  -moz-user-select: text;
  user-select: text;
}