/* 美化底部欄樣式 */
.footer {
  background: #101317;
  border-top: 1px solid rgba(255,255,255,0.08);
  padding: 22px 14px;
  color: #cfd6e6;
}
.footer a { color: #7fb3ff; text-decoration: none; transition: color .2s ease; }
.footer a:hover { color: #a9ccff; }

/* 內容區域居中限制寬度 */
.footer .columns,
.footer .social { max-width: 1200px; margin: 0 auto; }

/* 自適應排版：由 flex 改為 grid，更佳對齊與換行 */
.columns {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
}
.col { min-width: 0; }

.title {
  display: block;
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 8px;
  color: #e8edf7;
  position: relative;
}
.title::after {
  content: "";
  display: block;
  width: 24px;
  height: 2px;
  background: #2a6ef7;
  border-radius: 2px;
  margin-top: 5px;
}

.desc { columns: 2; color: #b4bed2; font-size: 13px; line-height: 1.6; }
.desc ul { list-style: none; padding: 0; margin: 0; }
.desc li { margin: 6px 0; }
.desc a { color: #9fc2ff; }
.desc a:hover { color: #c0d7ff; text-decoration: underline; }

.social { margin-top: 16px; display: flex; gap: 10px; align-items: center; }
.icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.12);
  color: #cfd6e6;
  text-decoration: none;
  box-shadow: 0 2px 6px rgba(0,0,0,0.12);
  transition: transform .15s ease, background .15s ease, color .15s ease;
}
.icon:hover { transform: translateY(-2px); background: rgba(255,255,255,0.12); color: #ffffff; }
.back-top {
  position: fixed;
  bottom: 20px;
  right: 20px;
  z-index: 4000;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 36px;
  padding: 0 14px;
  border-radius: 18px;
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.12);
  color: #e8edf7;
  text-decoration: none;
  box-shadow: 0 2px 6px rgba(0,0,0,0.12);
  backdrop-filter: saturate(140%) blur(6px);
  transition: transform .15s ease, background .15s ease, color .15s ease;
}
.back-top:hover { transform: translateY(-2px); background: rgba(255,255,255,0.12); color: #ffffff;}
.whatsapp-fab {
  position: fixed;
  bottom: 72px;
  right: 20px;
  z-index: 4000;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 58px;
  height: 58px;
  border-radius: 50%;
  background: rgba(37,211,102,0.12);
  border: 1px solid rgba(37,211,102,0.5);
  color: #25D366;
  text-decoration: none;
  box-shadow: 0 2px 6px rgba(0,0,0,0.12);
  backdrop-filter: saturate(140%) blur(6px);
  transition: transform .15s ease, background .15s ease, color .15s ease;
}
.whatsapp-fab svg { width: 100%; height: 100%; }
.whatsapp-fab:hover { transform: translateY(-2px); background: rgba(37,211,102,0.2); color: #2fe278; }
@media (max-width: 640px) {
  .back-top { bottom: 16px; right: 12px; height: 34px; padding: 0 12px; }
  .whatsapp-fab { bottom: 58px; right: 12px; width: 44px; height: 44px; }
}

@media (max-width: 640px) {
  .footer { padding: 18px 12px; }
  .columns { grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 12px; }
  .title { font-size: 14px; }
  .desc { font-size: 12.5px; }
}