:root {
  --orange: #f58220;
  --orange-dark: #e06f10;
  --text: #222;
  --muted: #555;
  --border: #ddd;
  --dark: #1a1a1a;
  --white: #fff;
}

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

body {
  font-family: Arial, Helvetica, "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  line-height: 1.6;
  background: var(--white);
}

a { color: var(--orange); text-decoration: none; }
a:hover { text-decoration: underline; }

.container {
  width: min(1100px, 94vw);
  margin: 0 auto;
}

/* Header */
.site-header {
  border-bottom: 1px solid var(--border);
  background: var(--white);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  gap: 16px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text);
  flex-shrink: 0;
}

.brand img { height: 42px; width: auto; }

.brand span {
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 18px;
  flex-wrap: wrap;
}

.main-nav a {
  color: var(--text);
  font-size: 0.9rem;
  text-decoration: none;
}

.main-nav a:hover,
.main-nav a.active {
  color: var(--orange);
  text-decoration: none;
}

.header-actions {
  display: flex;
  gap: 8px;
  flex-shrink: 0;
}

.btn-outline {
  display: inline-block;
  padding: 7px 14px;
  border: 1px solid #aaa;
  border-radius: 4px;
  color: var(--text);
  font-size: 0.85rem;
  text-decoration: none;
  background: var(--white);
}

.btn-outline:hover {
  background: #f5f5f5;
  text-decoration: none;
}

/* Hero */
.hero {
  text-align: center;
  padding: 48px 20px 36px;
}

.hero h1 {
  font-size: clamp(2.2rem, 5vw, 3rem);
  font-weight: 700;
  margin-bottom: 12px;
}

.hero .subtitle {
  font-size: 1.05rem;
  color: var(--muted);
  max-width: 720px;
  margin: 0 auto 28px;
}

.btn-download-hero {
  display: inline-block;
  background: var(--orange);
  color: var(--white);
  font-size: 1.15rem;
  font-weight: 700;
  padding: 14px 36px;
  border-radius: 6px;
  text-decoration: none;
  box-shadow: 0 4px 14px rgba(245, 130, 32, 0.45);
  transition: background 0.2s, transform 0.15s;
}

.btn-download-hero:hover {
  background: var(--orange-dark);
  text-decoration: none;
  transform: translateY(-1px);
}

/* Dark showcase */
.showcase {
  background: var(--dark);
  padding: 40px 0 50px;
}

.showcase-inner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 40px;
  flex-wrap: wrap;
}

.showcase-inner img.screenshot {
  max-width: min(680px, 90vw);
  height: auto;
  border-radius: 4px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
}

.showcase-icon {
  text-align: center;
  color: var(--white);
}

.showcase-icon img {
  width: 80px;
  height: auto;
  margin-bottom: 8px;
}

.showcase-icon span {
  display: block;
  font-size: 0.9rem;
}

/* Two-column content */
.content-section {
  padding: 48px 0 56px;
}

.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: start;
}

.content-section h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 20px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--orange);
  display: inline-block;
}

.content-section .intro p {
  margin-bottom: 16px;
  color: var(--muted);
  font-size: 0.95rem;
}

.features-list {
  list-style: none;
}

.features-list li {
  display: flex;
  gap: 14px;
  margin-bottom: 22px;
}

.feature-icon {
  width: 36px;
  height: 36px;
  flex-shrink: 0;
  background: #eee;
  border-radius: 4px;
  display: grid;
  place-items: center;
  font-size: 1.1rem;
  color: #666;
}

.features-list h3 {
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.features-list p {
  font-size: 0.85rem;
  color: var(--muted);
}

/* About page */
.about-page {
  padding: 48px 0 64px;
}

.about-page h1 {
  font-size: 2rem;
  margin-bottom: 24px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--orange);
  display: inline-block;
}

.about-page h2 {
  font-size: 1.2rem;
  margin: 28px 0 12px;
}

.about-page p,
.about-page li {
  color: var(--muted);
  margin-bottom: 12px;
  font-size: 0.95rem;
}

.about-page ul {
  padding-left: 24px;
  margin-bottom: 16px;
}

.back-link {
  display: inline-block;
  margin-bottom: 20px;
  font-weight: 600;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 24px 0;
  text-align: center;
  font-size: 0.85rem;
  color: var(--muted);
}

.site-footer a {
  font-weight: 600;
}

.scroll-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  width: 40px;
  height: 40px;
  background: var(--orange);
  color: var(--white);
  border: none;
  border-radius: 4px;
  font-size: 1.2rem;
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
  text-decoration: none;
  display: grid;
  place-items: center;
}

.scroll-top:hover {
  background: var(--orange-dark);
  color: var(--white);
}

@media (max-width: 768px) {
  .header-inner { flex-wrap: wrap; height: auto; padding: 12px 0; }
  .main-nav { order: 3; width: 100%; }
  .two-col { grid-template-columns: 1fr; }
  .showcase-inner { flex-direction: column; }
}