*{box-sizing:border-box;margin:0;padding:0}
:root{
  --primary:#2563eb;
  --green:#089170;
  --orange:#f97316;
  --purple:#9333ea;
  --gray1:#f3f4f6;
  --gray2:#e5e7eb;
  --gray3:#9ca3af;
  --text:#1f2937;
  --light-text:#6b7280;
  --card-bg:#fff;
  --shadow:0 2px 12px rgba(0,0,0,0.06);
}
.dark{
  --gray1:#1f2937;
  --gray2:#374151;
  --text:#f9fafb;
  --light-text:#d1d5db;
  --card-bg:#111827;
}
body{
  background:var(--gray1);
  color:var(--text);
  font-family:system-ui,-apple-system,Segoe UI,sans-serif;
  line-height:1.6;
  transition:0.3s background;
}

header{
  background:var(--card-bg);
  /* 只保留上下左右阴影，去掉底部单独阴影叠加 */
  box-shadow:0 2px 8px rgba(0,0,0,0.04);
  padding:14px 24px;
  position:sticky;top:0;z-index:99;
  display:flex;
  align-items:center;
  gap:20px;
  max-width:1000px;
  margin:0 auto;
  width:calc(100% - 48px);
  border-radius:10px;
}
.search-input{
  flex:1;max-width:600px;
  padding:9px 14px;border:1px solid var(--gray2);border-radius:6px;
  background:var(--gray1);color:var(--text);
}
.header-btns button{
  padding:7px 12px;border:none;border-radius:6px;cursor:pointer;
  margin:0 4px;background:var(--gray2);color:var(--text);
}
.son1{
  display:flex;
  gap:16px;
  align-items:center;
  /* 与下方内容左右对齐，和container同左右边距 */
  margin-left:24px;
  margin-right:24px;
}
.son1 a{
  color:var(--text);
  text-decoration:none;
  font-size:14px;
}
.son1 a:hover{
  color:var(--primary);
  text-decoration:underline;
}
@media (max-width:820px){
  header{
    flex-wrap:wrap;
  }
  .son1{
    width:100%;
    justify-content:flex-start;
    order:3;
  }
}
.container{
  max-width:1000px;margin:24px auto;padding:0 24px;
}
.main-content{display:flex;flex-direction:column;gap:20px}
.card{
  background:var(--card-bg);border-radius:10px;padding:22px;
  box-shadow:var(--shadow);
  position:relative;
  overflow:hidden;
}
.card::before{
  content:"";
  position:absolute;
  top:0;left:0;width:100%;height:4px;
  background:linear-gradient(90deg,var(--primary),var(--purple),var(--orange));
}
/* 单词头部左右布局：左图 + 右文字 */
.word-wrap{
  display:flex;
  gap:24px;
  align-items:flex-start;
}
.word-img-box{
  width:220px;
  flex-shrink:0;
}
.word-img-box img{
  width:100%;
  border-radius:8px;
  object-fit:cover;
}
.word-head{
  flex:1;
}
.word-head h1{font-size:42px;margin-bottom:8px}
.phonetic{color:var(--light-text);font-size:16px;margin-bottom:12px}
.play-btn{
  background:var(--primary);color:white;border:none;
  padding:6px 12px;border-radius:6px;cursor:pointer;margin-left:10px;
  display:inline-flex;align-items:center;gap:4px;
}
.play-btn::before{
  content:"🔊";
}
.tag{
  display:inline-block;padding:4px 10px;border-radius:20px;font-size:13px;color:#fff;margin-right:6px;
}
.tag-n{background:var(--primary)}
.tag-adj{background:var(--green)}
.tag-v{background:var(--orange)}
.word-ops{margin-top:14px;display:flex;gap:10px;flex-wrap:wrap}
.word-ops button{
  border:1px solid var(--gray2);background:transparent;
  padding:6px 12px;border-radius:6px;cursor:pointer;color:var(--text);
  display:flex;align-items:center;gap:4px;
}
.word-ops button:nth-child(1)::before{content:"⭐";}
.word-ops button:nth-child(2)::before{content:"📋";}
.word-ops button:nth-child(3)::before{content:"🔗";}
.word-ops button:nth-child(4)::before{content:"🖨️";}
.tab-wrap{margin-top:10px}
.tab-buttons{display:flex;border-bottom:1px solid var(--gray2);flex-wrap:wrap}
.tab-btn{
  padding:12px 20px;background:transparent;border:none;cursor:pointer;
  font-size:15px;color:var(--light-text);position:relative;
}
.tab-btn.active{color:var(--primary)}
.tab-btn.active::after{
  content:"";position:absolute;bottom:-1px;left:0;width:100%;height:2px;background:var(--primary);
}
.tab-panel{padding:20px 0;display:none}
.tab-panel.active{display:block}
.expand-btn{
  color:var(--primary);background:transparent;border:none;cursor:pointer;margin:8px 0;
  display:flex;align-items:center;gap:4px;
}
.expand-btn::after{content:"▼";font-size:12px;}
.para-block{margin:12px 0}
.para-block h4{margin:8px 0;color:var(--primary);display:flex;align-items:center;gap:6px}
.para-block h4::before{content:"📖";}
.syn-card{
  display:inline-block;padding:8px 12px;border:1px solid var(--gray2);
  border-radius:6px;margin:6px 4px;
}
.back-top{
  position:fixed;bottom:30px;right:30px;width:44px;height:44px;
  border-radius:50%;background:var(--primary);color:#fff;border:none;cursor:pointer;
  font-size:18px;
}
footer{
  text-align:center;color:var(--light-text);padding:30px 0;margin-top:40px;font-size:14px;
}
/* 移动端自适应：图片自动换行 */
@media (max-width:768px){
  .word-wrap{
    flex-direction:column;
  }
  .word-img-box{
    width:100%;
    max-width:300px;
  }
  .word-head h1{font-size:32px}
}
.search-btn{
  width:36px;height:36px;
  border:none;border-radius:6px;
  background:var(--primary);
  color:#fff;
  font-size:16px;
  cursor:pointer;
  flex-shrink:0;
}
.search-btn:hover{
  opacity:0.9;
}