/* ============ 坦克大战 TANK BATTLE - 网站信息页共享样式 (about/contact/privacy) ============ */
:root {
  --bg: #0b0b0b;
  --panel: #161616;
  --border: #2c2c2c;
  --text: #e8e8e8;
  --dim: #9a9a9a;
  --accent: #ffd700;
  --link: #85b7eb;
  --danger: #e5534b;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  background:
    radial-gradient(ellipse at 50% 0%, #1a1a1a 0%, var(--bg) 70%);
  color: var(--text);
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  line-height: 1.8;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  padding: 20px 16px 0;
}
.wrap { max-width: 880px; margin: 0 auto; width: 100%; }

/* 顶部导航 */
header.site-header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 18px;
  border-bottom: 2px solid var(--accent);
  padding-bottom: 14px;
  margin-bottom: 28px;
}
.site-logo {
  color: var(--accent);
  font-size: 20px;
  font-weight: bold;
  letter-spacing: 1px;
  text-decoration: none;
  white-space: nowrap;
}
.site-logo:hover { color: #ffe566; }
nav.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 2px;
}
nav.site-nav a {
  color: var(--dim);
  text-decoration: none;
  font-size: 15px;
  padding: 4px 12px;
  border-radius: 6px;
  border: 1px solid transparent;
  white-space: nowrap;
}
nav.site-nav a:hover { color: var(--text); border-color: var(--border); }
nav.site-nav a.active {
  color: var(--accent);
  border-color: var(--accent);
  background: rgba(255, 215, 0, 0.08);
}
.lang-btn {
  margin-left: auto;
  background: var(--panel);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 6px 14px;
  font-size: 13px;
  cursor: pointer;
}
.lang-btn:hover { border-color: var(--accent); color: var(--accent); }

/* 正文 */
h1 { font-size: 28px; color: var(--accent); margin-bottom: 6px; }
h2 {
  font-size: 18px;
  color: var(--accent);
  margin: 30px 0 10px;
  padding-left: 10px;
  border-left: 4px solid var(--accent);
}
p { margin-bottom: 12px; }
ul { margin: 4px 0 14px 22px; }
li { margin-bottom: 6px; }
a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }
.updated { color: var(--dim); font-size: 14px; margin-bottom: 26px; }

/* 特性卡片 (about) */
.features { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 12px; margin: 6px 0 18px; }
.feat {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 14px 16px;
}
.feat h3 { color: var(--accent); font-size: 15px; margin-bottom: 6px; }
.feat p { color: var(--dim); font-size: 13px; margin: 0; }

/* FAQ (about) */
details.faq {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px 16px;
  margin-bottom: 10px;
}
details.faq summary {
  cursor: pointer;
  color: var(--text);
  font-weight: bold;
  font-size: 15px;
}
details.faq summary:hover { color: var(--accent); }
details.faq p { margin: 10px 0 2px; color: var(--dim); font-size: 14px; }

/* 联系表单 (contact) */
.contact-form {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px 22px;
  margin: 8px 0 20px;
}
.contact-form label { display: block; font-size: 14px; color: var(--dim); margin: 14px 0 6px; }
.contact-form label:first-child { margin-top: 0; }
.contact-form input, .contact-form select, .contact-form textarea {
  width: 100%;
  background: #0d0d0d;
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 12px;
  font-size: 14px;
  font-family: inherit;
}
.contact-form input:focus, .contact-form select:focus, .contact-form textarea:focus {
  outline: none;
  border-color: var(--accent);
}
.contact-form textarea { min-height: 140px; resize: vertical; }
.contact-form .btn {
  margin-top: 18px;
  background: var(--accent);
  color: #1a1a00;
  border: none;
  border-radius: 8px;
  padding: 12px 28px;
  font-size: 15px;
  font-weight: bold;
  cursor: pointer;
}
.contact-form .btn:hover { background: #ffe566; }
.form-note { color: var(--dim); font-size: 13px; margin-top: 10px; }

/* 页脚 */
footer.site-footer {
  margin-top: 40px;
  border-top: 1px solid var(--border);
  padding: 18px 0 30px;
  text-align: center;
  color: var(--dim);
  font-size: 13px;
}
footer.site-footer a { color: var(--dim); margin: 0 8px; }
footer.site-footer a:hover { color: var(--accent); text-decoration: none; }

[data-lang="en"] { display: none; }
html[lang="en"] [data-lang="zh"] { display: none; }
html[lang="en"] [data-lang="en"] { display: block; }
html[lang="en"] h1[data-lang="en"] { display: block; }

@media (max-width: 640px) {
  body { padding: 14px 12px 0; }
  h1 { font-size: 22px; }
  .lang-btn { margin-left: 0; }
}