/* 会了吗背单词 官网（huilema.zackforge.com）
   品牌色 #047857（与应用图标一致）；无第三方依赖，系统字体栈。 */

:root {
  --brand: #047857;
  --brand-dark: #036c4f;
  --ink: #111827;
  --muted: #6b7280;
  --bg: #ffffff;
  --bg-alt: #f3f4f6;
  --border: #e5e7eb;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", "Microsoft YaHei", "PingFang SC", sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.7;
}

.container { max-width: 1080px; margin: 0 auto; padding: 0 20px; }

/* ---------- 头部 ---------- */
.site-header {
  position: sticky; top: 0; z-index: 10;
  background: rgba(255,255,255,.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; height: 60px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 17px; color: var(--ink); text-decoration: none; }
.brand-logo { width: 32px; height: 32px; }
.nav { display: flex; gap: 24px; }
.nav a { color: var(--muted); text-decoration: none; font-size: 15px; }
.nav a:hover { color: var(--brand); }

/* ---------- 首屏 ---------- */
.hero { padding: 72px 0 56px; text-align: center; background: linear-gradient(180deg, #ecfdf5 0%, #ffffff 100%); }
.hero-logo { width: 96px; height: 96px; }
.hero h1 { font-size: 40px; margin: 20px 0 12px; }
.slogan { font-size: 17px; color: #374151; margin: 0 auto 28px; max-width: 640px; }
.slogan b { color: var(--brand); }
.hero-actions { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.hero-note { color: var(--muted); font-size: 13px; margin-top: 14px; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-block; padding: 10px 22px; border-radius: 10px;
  font-size: 15px; text-decoration: none; cursor: pointer;
}
.btn-lg { padding: 14px 30px; font-size: 17px; }
.btn-disabled {
  background: #9ca3af; color: #fff; cursor: not-allowed;
}
.btn-ghost { border: 1.5px solid var(--brand); color: var(--brand); }
.btn-ghost:hover { background: var(--brand); color: #fff; }

/* ---------- 数据速览 ---------- */
.stats { background: var(--bg-alt); padding: 28px 0; }
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; text-align: center; }
.stat b { display: block; font-size: 26px; color: var(--brand); }
.stat span { color: var(--muted); font-size: 14px; }

/* ---------- 通用区块 ---------- */
.section { padding: 64px 0; }
.section-alt { background: var(--bg-alt); }
.section h2 { text-align: center; font-size: 30px; margin: 0 0 8px; }
.section-sub { text-align: center; color: var(--muted); margin: 0 0 40px; }

/* ---------- 功能卡片 ---------- */
.feature-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.card {
  background: #fff; border: 1px solid var(--border); border-radius: 14px;
  padding: 24px 20px; transition: box-shadow .15s ease, transform .15s ease;
}
.card:hover { box-shadow: 0 6px 20px rgba(0,0,0,.07); transform: translateY(-2px); }
.card-icon { font-size: 30px; }
.card h3 { font-size: 17px; margin: 12px 0 8px; }
.card p { font-size: 14px; color: #4b5563; margin: 0; }

/* ---------- 使用流程 ---------- */
.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.step {
  background: #fff; border-radius: 14px; padding: 28px 22px; text-align: center;
  border: 1px solid var(--border);
}
.step-num {
  display: inline-flex; align-items: center; justify-content: center;
  width: 40px; height: 40px; border-radius: 50%;
  background: var(--brand); color: #fff; font-size: 18px; font-weight: 700;
}
.step h3 { margin: 14px 0 8px; font-size: 17px; }
.step p { font-size: 14px; color: #4b5563; margin: 0; }

/* ---------- 下载区 ---------- */
.download-box {
  text-align: center; border: 1px solid var(--border); border-radius: 18px;
  padding: 48px 24px; background: linear-gradient(180deg, #ffffff, #ecfdf5);
}
.download-actions { margin-bottom: 18px; }
.download-note { color: var(--muted); font-size: 13px; margin: 0; }

/* ---------- 页脚 ---------- */
.site-footer { border-top: 1px solid var(--border); padding: 28px 0; background: var(--bg); }
.footer-inner { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px; }
.site-footer p { margin: 0; font-size: 14px; color: var(--muted); }

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 560px) {
  .hero h1 { font-size: 30px; }
  .feature-grid, .steps { grid-template-columns: 1fr; }
  .footer-inner { justify-content: center; text-align: center; }
}