/* ===== RESET & BASE ===== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  color: #26272a; line-height: 1.6; background: #fff;
}
a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; display: block; }

/* ===== COLOR VARIABLES (秒达云风格) ===== */
:root {
  --primary: #ee5050;
  --primary-dark: #df3838;
  --primary-light: #fef6f9;
  --accent: #ee9250;
  --text-dark: #26272a;
  --text-mid: #555c6a;
  --text-light: #737e97;
  --bg-gray: #f5f7fa;
  --bg-warm: #fef9f9;
  --white: #ffffff;
  --border: #e9f0fc;
  --gradient-primary: linear-gradient(135deg, #ee5050 0%, #ee9250 100%);
  --gradient-hero: linear-gradient(135deg, #fff5f5 0%, #fef4f4 50%, #f5f7fa 100%);
  --shadow-card: 0 2px 8px rgba(238,80,80,.06);
  --shadow-hover: 0 8px 24px rgba(238,80,80,.12);
}

/* ===== UTILITY ===== */
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

.text-center { text-align: center; }

.gradient-text {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ===== BUTTONS ===== */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 28px; border-radius: 100px; font-size: 15px;
  font-weight: 600; cursor: pointer; border: none; transition: all .25s ease;
}
.btn-primary {
  background: var(--gradient-primary); color: #fff;
  box-shadow: 0 4px 12px rgba(238,80,80,.25);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 6px 20px rgba(238,80,80,.35); }
.btn-outline {
  background: transparent; color: var(--primary);
  border: 2px solid var(--primary);
}
.btn-outline:hover { background: var(--primary-light); }
.btn-white {
  background: #fff; color: var(--primary); font-weight: 700;
}
.btn-white:hover { transform: translateY(-2px); box-shadow: 0 6px 20px rgba(0,0,0,.15); }
.login-btn { padding:8px 16px; }
.register-btn { padding:8px 20px; }
.login-btn, .register-btn { font-size:14px; }

/* ===== NAVBAR ===== */
.navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  background: rgba(255,255,255,.95); backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border); height: 68px;
}
.navbar .container { display: flex; align-items: center; justify-content: space-between; height: 100%; }
.nav-logo { display: flex; align-items: center; gap: 8px; font-weight: 700; font-size: 22px; }
.nav-logo .logo-icon {
  width: 36px; height: 36px; border-radius: 10px;
  background: var(--gradient-primary); display: flex; align-items: center; justify-content: center;
  color: #fff; font-weight: 700; font-size: 18px;
}
.nav-links { display: flex; align-items: center; gap: 32px; }
.nav-links a { font-size: 15px; color: var(--text-mid); font-weight: 500; transition: color .2s; }
.nav-links a:hover { color: var(--primary); }
.nav-right { display: flex; align-items: center; gap: 16px; }
.nav-right .btn { padding: 8px 20px; font-size: 14px; }

/* ===== LANGUAGE SWITCHER ===== */
.lang-switcher { position: relative; }
.lang-switcher-btn {
  display: flex; align-items: center; gap: 6px; height: 36px;
  padding: 0 8px;font-size: 18px; color: var(--text-mid);
  cursor: pointer; border-radius: 6px; outline: none;
  background: transparent; border: none;
  transition: color .2s, background .2s;
}
.lang-switcher-btn:hover { color: var(--primary); background: var(--primary-light); }
.lang-switcher-btn .arrow-icon { font-size: 12px; transition: transform .2s; }
.lang-switcher.open .lang-switcher-btn .arrow-icon { transform: rotate(180deg); }
.lang-dropdown {
  position: absolute; top: calc(100% + 8px); right: 0;
  min-width: 130px; background: #fff; border-radius: 8px;
  box-shadow: 0 4px 16px rgba(0,0,0,.1); border: 1px solid var(--border);
  padding: 4px; z-index: 1001;
  opacity: 0; visibility: hidden; transform: translateY(-4px);
  transition: all .2s ease;
}
.lang-switcher.open .lang-dropdown { opacity: 1; visibility: visible; transform: translateY(0); }
.lang-option {
  display: block; width: 100%; padding: 8px 16px; font-size: 14px;
  color: var(--text-mid); border-radius: 6px; cursor: pointer;
  background: transparent; border: none; text-align: left;
  transition: all .15s;
}
.lang-option:hover { background: var(--bg-gray); }
.lang-option.is-active { color: var(--primary); background: var(--primary-light); font-weight: 600; }

/* ===== FOOTER ===== */
.footer { background: #1a1a2e; color: rgba(255,255,255,.7); padding: 64px 0 32px; }
.footer-grid { display: grid; grid-template-columns: 2fr repeat(4, 1fr); gap: 40px; margin-bottom: 48px; }
.footer-brand .logo { font-size: 20px; font-weight: 700; color: #fff; margin-bottom: 12px; }
.footer-brand p { font-size: 14px; line-height: 1.7; max-width: 280px; }
.footer-col h4 { color: #fff; font-size: 14px; font-weight: 600; margin-bottom: 16px; }
.footer-col a { display: block; font-size: 14px; padding: 5px 0; transition: color .2s; }
.footer-col a:hover { color: var(--primary); }
.footer-bottom { border-top: 1px solid rgba(255,255,255,.08); padding-top: 24px; display: flex; justify-content: space-between; align-items: center; font-size: 13px; }
.footer-bottom .social { display: flex; gap: 20px; }

/* ===== RESPONSIVE ===== */
@media (max-width: 1024px) {
  .footer-grid { grid-template-columns: repeat(3, 1fr); }
}

@media (max-width: 930px) {
  .nav-logo { font-size: 16px; }
  .login-btn, .register-btn { font-size:12px!important; }
  .nav-links a { font-size: 12px; }
}

@media (max-width: 835px) {
  .nav-logo .logo-icon { width:30px;height: 30px; }
  .nav-logo { font-size: 14px; }
  .login-btn, .register-btn { padding: 6px 14px!important; font-size:12px!important; }
  .nav-right { gap: 8px; }
  .nav-links { display: none; }
  .container { padding: 0 12px; }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
}