/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --primary: #e02020;
  --primary-dark: #b81818;
  --primary-light: #ff4d4d;
  --secondary: #ff6b35;
  --accent: #ffb300;
  --dark: #1a1a2e;
  --dark2: #16213e;
  --dark3: #0f3460;
  --text: #2d2d2d;
  --text-muted: #666;
  --text-light: #999;
  --bg: #fff;
  --bg2: #f8f9fa;
  --bg3: #f0f4ff;
  --border: #e8e8e8;
  --radius: 12px;
  --radius-lg: 20px;
  --shadow: 0 4px 24px rgba(0,0,0,.08);
  --shadow-lg: 0 8px 48px rgba(0,0,0,.14);
  --transition: .25s ease;
}

html { scroll-behavior: smooth; }

body {
  font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  font-size: 16px;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
ul, ol { list-style: none; }
button { cursor: pointer; border: none; background: none; font-family: inherit; }

/* ===== Utility ===== */
.container { max-width: 1160px; margin: 0 auto; padding: 0 24px; }
.section { padding: 80px 0; }
.section-sm { padding: 56px 0; }
.text-center { text-align: center; }
.text-muted { color: var(--text-muted); }

.section-label {
  display: inline-block;
  background: linear-gradient(135deg, #ffe0e0, #ffd6b3);
  color: var(--primary);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  padding: 4px 14px;
  border-radius: 99px;
  margin-bottom: 14px;
}

.section-title {
  font-size: clamp(26px, 4vw, 42px);
  font-weight: 800;
  color: var(--dark);
  line-height: 1.25;
  margin-bottom: 16px;
}

.section-sub {
  font-size: 17px;
  color: var(--text-muted);
  max-width: 620px;
  margin: 0 auto 48px;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  border-radius: 99px;
  font-size: 16px;
  font-weight: 600;
  transition: var(--transition);
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: #fff;
  box-shadow: 0 4px 20px rgba(224,32,32,.3);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(224,32,32,.4);
}

.btn-outline {
  border: 2px solid var(--primary);
  color: var(--primary);
  background: transparent;
}
.btn-outline:hover {
  background: var(--primary);
  color: #fff;
}

.btn-white {
  background: #fff;
  color: var(--primary);
  box-shadow: 0 4px 20px rgba(0,0,0,.12);
}
.btn-white:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(0,0,0,.2);
}

.btn-lg { padding: 18px 44px; font-size: 18px; }
.btn-sm { padding: 10px 22px; font-size: 14px; }

/* ===== Nav ===== */
.nav {
  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 rgba(0,0,0,.06);
  transition: var(--transition);
}

.nav-inner {
  display: flex;
  align-items: center;
  height: 64px;
  gap: 0;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 20px;
  font-weight: 800;
  color: var(--primary);
  margin-right: auto;
}

.nav-logo-icon {
  width: 36px; height: 36px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-links a {
  padding: 8px 16px;
  border-radius: 8px;
  font-size: 15px;
  color: var(--text);
  font-weight: 500;
  transition: var(--transition);
}
.nav-links a:hover, .nav-links a.active {
  background: #fff0f0;
  color: var(--primary);
}

.nav-cta { margin-left: 16px; }

.nav-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
  margin-left: auto;
}
.nav-hamburger span {
  display: block;
  width: 22px; height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: var(--transition);
}

/* ===== Hero ===== */
.hero {
  padding-top: 64px;
  min-height: 100vh;
  display: flex;
  align-items: center;
  background: linear-gradient(160deg, #fff 0%, #fff5f5 40%, #fff9f0 100%);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -200px; right: -200px;
  width: 700px; height: 700px;
  background: radial-gradient(circle, rgba(224,32,32,.06) 0%, transparent 70%);
  border-radius: 50%;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -100px; left: -100px;
  width: 500px; height: 500px;
  background: radial-gradient(circle, rgba(255,107,53,.05) 0%, transparent 70%);
  border-radius: 50%;
}

.hero-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: linear-gradient(135deg, #fff0f0, #ffe8d6);
  border: 1px solid rgba(224,32,32,.15);
  color: var(--primary);
  font-size: 13px;
  font-weight: 600;
  padding: 6px 14px;
  border-radius: 99px;
  margin-bottom: 20px;
}

.hero-title {
  font-size: clamp(32px, 5vw, 56px);
  font-weight: 900;
  line-height: 1.15;
  color: var(--dark);
  margin-bottom: 20px;
}

.hero-title em {
  font-style: normal;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-desc {
  font-size: 18px;
  color: var(--text-muted);
  margin-bottom: 32px;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-bottom: 40px;
}

.hero-stats {
  display: flex;
  gap: 32px;
  padding-top: 28px;
  border-top: 1px solid var(--border);
}

.hero-stat-num {
  font-size: 28px;
  font-weight: 800;
  color: var(--primary);
  line-height: 1;
}

.hero-stat-label {
  font-size: 13px;
  color: var(--text-muted);
  margin-top: 4px;
}

/* Hero visual */
.hero-visual {
  position: relative;
}

.hero-card {
  background: #fff;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}

.hero-card-header {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  padding: 20px 24px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.hero-card-header span {
  color: rgba(255,255,255,.9);
  font-size: 15px;
  font-weight: 600;
}

.hero-card-body {
  padding: 24px;
}

.translate-box {
  background: var(--bg2);
  border-radius: var(--radius);
  padding: 20px;
  margin-bottom: 16px;
}

.translate-lang {
  font-size: 12px;
  color: var(--text-light);
  margin-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.translate-text {
  font-size: 16px;
  color: var(--text);
  line-height: 1.6;
}

.translate-divider {
  display: flex;
  align-items: center;
  gap: 12px;
  margin: 12px 0;
  color: var(--text-light);
  font-size: 13px;
}

.translate-divider::before,
.translate-divider::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border);
}

.translate-result {
  background: linear-gradient(135deg, #fff5f5, #fff9f0);
  border: 1px solid rgba(224,32,32,.1);
  border-radius: var(--radius);
  padding: 20px;
}

.translate-result .translate-text {
  color: var(--primary);
  font-weight: 600;
  font-size: 18px;
}

.feature-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 16px;
}

.feature-tag {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 99px;
  padding: 5px 12px;
  font-size: 13px;
  color: var(--text-muted);
}

/* ===== Features ===== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.feature-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  transition: var(--transition);
}

.feature-card:hover {
  border-color: transparent;
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
}

.feature-icon {
  width: 56px; height: 56px;
  background: linear-gradient(135deg, #fff0f0, #ffe8d6);
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}

.feature-title {
  font-size: 18px;
  font-weight: 700;
  color: var(--dark);
  margin-bottom: 10px;
}

.feature-desc {
  font-size: 15px;
  color: var(--text-muted);
  line-height: 1.7;
}

/* ===== Language grid ===== */
.lang-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 14px;
}

.lang-item {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 14px;
  text-align: center;
  transition: var(--transition);
}

.lang-item:hover {
  border-color: var(--primary);
  background: #fff5f5;
}

.lang-item .flag { font-size: 28px; display: block; margin-bottom: 6px; }
.lang-item .name { font-size: 13px; font-weight: 600; color: var(--text); }
.lang-item .native { font-size: 12px; color: var(--text-light); }

/* ===== Platform cards ===== */
.platform-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.platform-card {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px 20px;
  text-align: center;
  transition: var(--transition);
}

.platform-card:hover {
  border-color: var(--primary);
  box-shadow: var(--shadow);
}

.platform-icon {
  width: 52px; height: 52px;
  margin: 0 auto 14px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.platform-name {
  font-size: 16px;
  font-weight: 700;
  color: var(--dark);
  margin-bottom: 6px;
}

.platform-version {
  font-size: 13px;
  color: var(--text-light);
  margin-bottom: 16px;
}

/* ===== FAQ ===== */
.faq-list { max-width: 860px; margin: 0 auto; }

.faq-item {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 12px;
  overflow: hidden;
  transition: var(--transition);
}

.faq-item.open {
  border-color: rgba(224,32,32,.25);
  box-shadow: 0 2px 12px rgba(224,32,32,.06);
}

.faq-question {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 24px;
  cursor: pointer;
  font-size: 16px;
  font-weight: 600;
  color: var(--dark);
  gap: 16px;
  user-select: none;
}

.faq-question:hover { color: var(--primary); }

.faq-chevron {
  flex-shrink: 0;
  width: 24px; height: 24px;
  transition: transform var(--transition);
}

.faq-item.open .faq-chevron { transform: rotate(180deg); }

.faq-answer {
  display: none;
  padding: 0 24px 20px;
  font-size: 15px;
  color: var(--text-muted);
  line-height: 1.75;
}

.faq-item.open .faq-answer { display: block; }

/* ===== CTA Banner ===== */
.cta-banner {
  background: linear-gradient(135deg, var(--dark), var(--dark3));
  color: #fff;
  padding: 80px 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.cta-banner::before {
  content: '';
  position: absolute;
  top: -100px; left: 50%;
  transform: translateX(-50%);
  width: 600px; height: 600px;
  background: radial-gradient(circle, rgba(224,32,32,.15) 0%, transparent 70%);
  border-radius: 50%;
}

.cta-title {
  font-size: clamp(28px, 4vw, 44px);
  font-weight: 800;
  margin-bottom: 16px;
  position: relative;
}

.cta-sub {
  font-size: 18px;
  color: rgba(255,255,255,.7);
  margin-bottom: 36px;
  position: relative;
}

.cta-actions {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 16px;
  position: relative;
}

/* ===== Footer ===== */
.footer {
  background: var(--dark);
  color: rgba(255,255,255,.7);
  padding: 60px 0 30px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  padding-bottom: 48px;
  border-bottom: 1px solid rgba(255,255,255,.08);
  margin-bottom: 32px;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
}

.footer-brand-name {
  font-size: 18px;
  font-weight: 800;
  color: #fff;
}

.footer-desc {
  font-size: 14px;
  line-height: 1.7;
  margin-bottom: 20px;
}

.footer-col-title {
  font-size: 14px;
  font-weight: 700;
  color: #fff;
  margin-bottom: 16px;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-links a {
  font-size: 14px;
  transition: color var(--transition);
}
.footer-links a:hover { color: #fff; }

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 13px;
  flex-wrap: wrap;
  gap: 10px;
}

/* ===== Download Page Specific ===== */
.download-hero {
  padding-top: 64px;
  background: linear-gradient(160deg, var(--dark) 0%, var(--dark3) 100%);
  color: #fff;
  padding-bottom: 80px;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.download-hero::before {
  content: '';
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  width: 800px; height: 800px;
  background: radial-gradient(circle, rgba(224,32,32,.12) 0%, transparent 65%);
  border-radius: 50%;
}

.download-hero .container { position: relative; z-index: 1; }

.download-hero-title {
  font-size: clamp(32px, 5vw, 56px);
  font-weight: 900;
  margin-bottom: 16px;
  margin-top: 24px;
}

.download-hero-sub {
  font-size: 18px;
  color: rgba(255,255,255,.75);
  max-width: 560px;
  margin: 0 auto 48px;
}

/* Windows Featured Card */
.win-featured {
  background: linear-gradient(135deg, #fff, #fff8f8);
  border: 2px solid var(--primary);
  border-radius: 24px;
  padding: 48px 40px;
  position: relative;
  overflow: hidden;
  margin-bottom: 40px;
  box-shadow: 0 12px 48px rgba(224,32,32,.12);
}

.win-featured::before {
  content: '';
  position: absolute;
  top: 0; right: 0;
  width: 300px; height: 300px;
  background: radial-gradient(circle, rgba(224,32,32,.05) 0%, transparent 70%);
  border-radius: 50%;
}

.win-featured-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--primary);
  color: #fff;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 1px;
  text-transform: uppercase;
  padding: 5px 14px;
  border-radius: 99px;
  margin-bottom: 20px;
}

.win-featured-inner {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 40px;
  align-items: center;
}

.win-title {
  font-size: 32px;
  font-weight: 800;
  color: var(--dark);
  margin-bottom: 10px;
}

.win-version {
  font-size: 14px;
  color: var(--text-light);
  margin-bottom: 20px;
}

.win-features {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 28px;
}

.win-feature-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: rgba(224,32,32,.06);
  border: 1px solid rgba(224,32,32,.15);
  color: var(--primary);
  border-radius: 99px;
  padding: 5px 12px;
  font-size: 13px;
  font-weight: 500;
}

.win-size {
  font-size: 14px;
  color: var(--text-light);
}

.win-download-btn {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: #fff;
  border-radius: 99px;
  padding: 18px 44px;
  font-size: 18px;
  font-weight: 700;
  box-shadow: 0 6px 24px rgba(224,32,32,.35);
  transition: var(--transition);
  display: inline-flex;
  align-items: center;
  gap: 10px;
  white-space: nowrap;
}

.win-download-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 32px rgba(224,32,32,.45);
}

.win-download-btn:disabled {
  opacity: .75;
  transform: none;
}

/* Other platform cards */
.other-platforms {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.dl-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px 24px;
  text-align: center;
  transition: var(--transition);
}

.dl-card:hover {
  border-color: rgba(224,32,32,.2);
  box-shadow: var(--shadow);
  transform: translateY(-2px);
}

.dl-card-icon {
  width: 64px; height: 64px;
  margin: 0 auto 18px;
  border-radius: 18px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.dl-card-name { font-size: 20px; font-weight: 700; color: var(--dark); margin-bottom: 6px; }
.dl-card-version { font-size: 13px; color: var(--text-light); margin-bottom: 6px; }
.dl-card-size { font-size: 13px; color: var(--text-light); margin-bottom: 20px; }

.dl-card-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--bg2);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 99px;
  padding: 10px 24px;
  font-size: 15px;
  font-weight: 600;
  transition: var(--transition);
}

.dl-card-btn:hover {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}

.dl-card-btn:disabled {
  opacity: .7;
  pointer-events: none;
}

/* Steps */
.steps-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.step-card {
  text-align: center;
  padding: 32px 20px;
  position: relative;
}

.step-card::after {
  content: '';
  position: absolute;
  top: 46px; right: -12%;
  width: 24%; height: 2px;
  background: linear-gradient(90deg, var(--border), transparent);
}

.step-card:last-child::after { display: none; }

.step-num {
  width: 48px; height: 48px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  color: #fff;
  font-size: 20px;
  font-weight: 800;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
}

.step-title { font-size: 16px; font-weight: 700; color: var(--dark); margin-bottom: 8px; }
.step-desc { font-size: 14px; color: var(--text-muted); line-height: 1.6; }

/* Requirements */
.req-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.req-card {
  background: var(--bg2);
  border-radius: var(--radius-lg);
  padding: 32px;
}

.req-title {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 18px;
  font-weight: 700;
  color: var(--dark);
  margin-bottom: 20px;
}

.req-list { display: flex; flex-direction: column; gap: 12px; }

.req-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
  font-size: 14px;
}

.req-row:last-child { border-bottom: none; }
.req-row-label { color: var(--text-muted); }
.req-row-val { font-weight: 600; color: var(--dark); }

/* ===== Spinner ===== */
@keyframes spin { to { transform: rotate(360deg); } }
.spinner { animation: spin .8s linear infinite; }

/* ===== Responsive ===== */
@media (max-width: 1024px) {
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .platform-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  .nav-links, .nav-cta { display: none; }
  .nav-hamburger { display: flex; }
  .hero-inner { grid-template-columns: 1fr; gap: 40px; }
  .hero-visual { display: none; }
  .hero-stats { gap: 20px; }
  .features-grid { grid-template-columns: 1fr; }
  .lang-grid { grid-template-columns: repeat(3, 1fr); }
  .platform-grid { grid-template-columns: 1fr 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 32px; }
  .win-featured-inner { grid-template-columns: 1fr; text-align: center; }
  .other-platforms { grid-template-columns: 1fr; }
  .steps-grid { grid-template-columns: 1fr 1fr; }
  .req-grid { grid-template-columns: 1fr; }
  .step-card::after { display: none; }
}

@media (max-width: 480px) {
  .section { padding: 56px 0; }
  .hero-actions { flex-direction: column; }
  .lang-grid { grid-template-columns: repeat(2, 1fr); }
  .steps-grid { grid-template-columns: 1fr; }
}

/* Mobile Nav Open */
.nav-mobile-open .nav-links {
  display: flex;
  flex-direction: column;
  position: fixed;
  top: 64px; left: 0; right: 0;
  background: #fff;
  padding: 20px;
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow);
  z-index: 999;
}

.nav-mobile-open .nav-links a {
  padding: 12px 16px;
  display: block;
  width: 100%;
}

.nav-mobile-open .nav-cta {
  display: flex;
  margin: 0 20px 20px;
  position: fixed;
  top: 64px + 200px;
  z-index: 999;
}