/* ============ 块学英语 · 现代简约风（对齐参考站设计语言） ============ */
:root {
  --green: #287f70;
  --green-dark: #1d6256;
  --green-tint: rgb(40 127 112 / .08);
  --green-line: rgb(40 127 112 / .25);
  --ink: rgb(0 0 0 / .88);
  --secondary: rgb(0 0 0 / .75);
  --tertiary: rgb(0 0 0 / .6);
  --quiet: rgb(0 0 0 / .46);
  --line: rgb(0 0 0 / .09);
  --card: #ffffff;
  --bg: #f7faf8;
  --gold: #b98a10;
  --radius: 16px;
  --shadow: 0 1px 2px rgb(0 0 0 / .04), 0 8px 24px rgb(0 0 0 / .06);
  --shadow-lg: 0 2px 4px rgb(0 0 0 / .05), 0 16px 40px rgb(0 0 0 / .1);
  font-size: 16px;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background: var(--bg);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; color: inherit; }
img { max-width: 100%; display: block; }
input { font: inherit; }

/* ---------- 顶栏 ---------- */
.topbar {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; justify-content: space-between; gap: 24px;
  height: 76px; padding: 0 clamp(16px, 4vw, 40px);
  background: rgba(247, 250, 248, .92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}
.brand { display: flex; align-items: center; white-space: nowrap; }
.brand .brand-logo {
  height: 46px; width: auto; display: block;
}
.nav {
  display: flex; align-items: center; gap: 28px; font-size: 14px; color: var(--tertiary);
  position: absolute; left: 50%; top: 50%; transform: translate(-50%, -50%);
}
@media (max-width: 1100px) {
  /* 窄屏下绝对居中会与品牌区重叠，退回弹性布局、在剩余空间中居中 */
  .nav { position: static; transform: none; margin: 0 auto; gap: 20px; }
}
.nav a { padding: 6px 2px; transition: color .15s; white-space: nowrap; }
@media (max-width: 900px) {
  /* 平板宽度：收紧导航间距与品牌副标题，防止链接文字竖排 */
  .topbar { gap: 12px; }
  .nav { gap: 14px; font-size: 13px; }
  .btn-login { padding: 10px 14px; font-size: 13px; }
}
.nav a:hover { color: var(--green); }
.nav a.on { color: var(--green); font-weight: 600; }
.btn-login {
  border: 1px solid var(--green-line); background: transparent; color: var(--green);
  font-weight: 600; font-size: 14px; padding: 11px 20px; border-radius: 99px;
  transition: background .15s, color .15s; white-space: nowrap;
}
.btn-login:hover { background: var(--green); color: #fff; }

/* ---------- 手机菜单 ---------- */
.nav-burger {
  display: none; border: 1px solid var(--line); background: #fff; color: var(--ink);
  border-radius: 99px; width: 42px; height: 42px; font-size: 1.15rem; font-weight: 700;
  flex-shrink: 0; align-items: center; justify-content: center;
}
.mobile-menu {
  display: none; position: absolute; top: 100%; left: 0; right: 0; z-index: 49;
  background: rgba(255,255,255,.98); backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line); box-shadow: 0 20px 32px rgb(0 0 0 / .08);
}
.mobile-menu.open { display: block; }
.mobile-menu a {
  display: flex; align-items: center; gap: 12px; padding: 8px 24px; font-weight: 600; color: var(--secondary);
  border-top: 1px solid var(--line); font-size: 1rem;
}
.mm-ico {
  width: 30px; height: 30px; object-fit: contain; flex: none;
  image-rendering: pixelated;
}
.mobile-menu a:active, .mobile-menu a.on { color: var(--green); background: var(--green-tint); }

/* ---------- 视图容器 ---------- */
.view { display: none; max-width: 1240px; margin: 0 auto; padding: 34px clamp(16px, 4vw, 40px) 80px; animation: fade .3s; }
.view.on { display: block; }
@keyframes fade { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; } }

/* ---------- Hero ---------- */
.hero { text-align: center; padding: 30px 0 0; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 14px; font-weight: 500; color: var(--green);
  letter-spacing: .04em; margin-bottom: 18px;
}
.live-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--green); box-shadow: 0 0 0 5px var(--green-tint); }
.hero h1 {
  font-size: clamp(34px, 5.2vw, 64px); letter-spacing: -.05em; line-height: 1.2;
  font-weight: 750; color: var(--ink);
}
.hero h1 .hl { color: var(--green); }
.hero .sub { font-size: 18px; color: var(--tertiary); line-height: 1.7; margin: 22px 0 28px; }
.hero-actions { display: flex; align-items: center; justify-content: center; gap: 24px; }
.hero-note { font-size: 12px; color: var(--quiet); margin-top: 16px; }

/* ---------- 倾斜滚动单词墙 ---------- */
.universe {
  position: relative; isolation: isolate; overflow: hidden;
  height: 480px; margin: 20px auto 0;
  mask-image: linear-gradient(to bottom, transparent, #000 12%, #000 80%, transparent);
  -webkit-mask-image: linear-gradient(to bottom, transparent, #000 12%, #000 80%, transparent);
}
.wall { position: absolute; width: 1700px; left: 50%; top: 60px; margin-left: -850px; transform: rotate(-7deg); }
.wall-row { display: flex; width: max-content; gap: 12px; margin-bottom: 12px; animation: drift 80s linear infinite; }
.wall-row:nth-child(even) { animation-direction: reverse; animation-duration: 95s; }
.wall-tile {
  width: 125px; height: 104px; border-radius: 12px; overflow: hidden; flex: none;
  background: #fff; box-shadow: 0 1px 2px rgb(0 0 0 / .06), 0 6px 16px rgb(0 0 0 / .08);
}
.wall-tile img { width: 100%; height: 100%; object-fit: cover; }
@keyframes drift { to { transform: translateX(-50%); } }

/* ---------- 演示卡 ---------- */
.demo-wrap { max-width: 560px; margin: 10px auto 0; }
.demo-hint { text-align: center; color: var(--quiet); margin: 26px 0 14px; font-weight: 500; font-size: 14px; }
.section-title { text-align: center; font-size: clamp(26px, 3.4vw, 40px); letter-spacing: -.045em; font-weight: 750; margin: 70px 0 10px; }
.section-desc { text-align: center; color: var(--tertiary); margin-bottom: 28px; line-height: 1.7; }

/* ---------- 模块卡 / 主题卡 ---------- */
.mod-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 20px; margin-top: 26px; }
.mod-card, .cat-card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  box-shadow: var(--shadow); transition: .18s; display: block; overflow: hidden;
}
.mod-card { padding: 26px; }
.mod-card:hover, .cat-card:hover { transform: translateY(-4px); border-color: var(--green-line); box-shadow: var(--shadow-lg); }
.mod-card h3 { margin: 12px 0 8px; font-size: 1.2rem; letter-spacing: -.02em; }
.mod-card p { color: var(--tertiary); line-height: 1.7; font-size: .95rem; }
.mod-card .meta { margin-top: 14px; display: flex; gap: 8px; flex-wrap: wrap; }
.mod-img { width: 100%; height: 150px; object-fit: cover; border-radius: 12px; margin-bottom: 8px; background: var(--bg); }
.badge {
  font-size: .78rem; font-weight: 600; padding: 4px 12px; border-radius: 99px;
  background: var(--green-tint); color: var(--green); border: 1px solid var(--green-line);
}
.cat-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 18px; }
.cat-cover { height: 132px; background: var(--bg); position: relative; }
.img-tag {
  position: absolute; top: 12px; left: 12px; z-index: 1;
  font-size: 12px; font-weight: 500; color: #fff; line-height: 1.4;
  letter-spacing: .02em; text-shadow: 0 1px 2px rgba(0, 0, 0, .35);
  background-image: linear-gradient(120deg,
    rgba(255, 94, 158, .5), rgba(255, 170, 60, .5), rgba(80, 220, 140, .5),
    rgba(70, 160, 255, .5), rgba(160, 90, 255, .5), rgba(255, 94, 158, .5));
  background-size: 400% 100%;
  animation: tagFlow 7s linear infinite;
  -webkit-backdrop-filter: blur(10px) saturate(1.5); backdrop-filter: blur(10px) saturate(1.5);
  padding: 3px 9px; border-radius: 6px; pointer-events: none; white-space: nowrap;
}
@keyframes tagFlow { from { background-position: 0% 50%; } to { background-position: 100% 50%; } }
.cat-cover img { width: 100%; height: 100%; object-fit: cover; }
.cat-cover .cover-fallback, .cat-cover .scene-img, .cat-cover .hit-img { width: 100%; height: 100%; object-fit: cover; }
.cat-cover { padding: 0 !important; overflow: hidden; }
.img-tag.lvb0 {
  background-image: linear-gradient(120deg,
    rgba(64, 150, 255, .55), rgba(60, 220, 200, .55), rgba(130, 90, 255, .55),
    rgba(64, 150, 255, .55));
}
.img-tag.lvb1 {
  background-image: linear-gradient(120deg,
    rgba(255, 170, 40, .55), rgba(255, 110, 90, .55), rgba(255, 210, 80, .55),
    rgba(255, 170, 40, .55));
}
.img-tag.lvb2 {
  background-image: linear-gradient(120deg,
    rgba(255, 70, 90, .55), rgba(230, 60, 180, .55), rgba(140, 70, 255, .55),
    rgba(255, 70, 90, .55));
}
.cat-body { padding: 15px 18px 17px; }
.cat-body .cnt { font-size: .8rem; color: var(--quiet); font-weight: 500; }
.cat-body h4 { margin: 5px 0 6px; font-size: 1.06rem; letter-spacing: -.01em; }
.cat-body p { font-size: .86rem; color: var(--tertiary); line-height: 1.6; }

/* ---------- 搜索 ---------- */
.search-row { display: flex; gap: 10px; margin-bottom: 22px; max-width: 640px; }
.search-row input {
  flex: 1; border: 1px solid var(--line); border-radius: 12px; padding: 12px 18px;
  font-size: 1rem; outline: none; background: #fff; transition: border-color .15s;
}
.search-row input:focus { border-color: var(--green); }
.search-row input::placeholder { color: var(--quiet); }

/* ---------- 按钮 ---------- */
.btn {
  border: 1px solid var(--line); background: #fff; border-radius: 99px;
  padding: 10px 20px; font-weight: 600; font-size: 14px; color: var(--secondary);
  transition: .15s; display: inline-flex; align-items: center; gap: 6px;
}
.btn:hover { border-color: var(--green-line); color: var(--green); }
.btn.primary {
  background: var(--green); border-color: var(--green); color: #fff;
  padding: 13px 26px; font-size: 15px; font-weight: 600;
}
.btn.primary:hover { background: var(--green-dark); color: #fff; transform: translateY(-2px); }

/* ---------- 阅读器 ---------- */
.reader-top { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; margin-bottom: 18px; }
.progress { margin-left: auto; font-weight: 600; color: var(--tertiary); font-variant-numeric: tabular-nums; font-size: 14px; }
.word-card {
  max-width: 560px; margin: 0 auto; background: var(--card);
  border: 1px solid var(--line); border-radius: 20px; box-shadow: var(--shadow-lg);
  padding: 30px 28px 24px;
}
.card-img {
  width: 220px; height: 220px; margin: 0 auto; object-fit: cover; border-radius: 14px;
  background: var(--bg); border: 1px solid var(--line);
}
.word-head { text-align: center; margin-top: 18px; }
.word-head .en { font-size: 2rem; font-weight: 750; letter-spacing: -.03em; }
.word-head .ipa { color: var(--green); font-weight: 500; margin-left: 8px; font-size: 1.1rem; }
.word-head .zh { color: var(--tertiary); margin-top: 4px; font-size: 1.02rem; }
.play-word {
  display: flex; align-items: center; gap: 8px; margin: 16px auto 0;
  border: 0; background: var(--green); color: #fff;
  border-radius: 99px; padding: 12px 26px; font-weight: 600; font-size: 1rem;
  transition: background .15s, transform .15s;
}
.play-word:hover { background: var(--green-dark); transform: translateY(-1px); }
.play-word.speaking { animation: pulse 0.8s infinite; }
@keyframes pulse { 50% { transform: scale(1.04); } }
.lv-tabs { display: flex; gap: 8px; justify-content: center; margin: 22px 0 10px; }
.lv-tab {
  border: 1px solid var(--line); background: #fff; border-radius: 99px;
  padding: 7px 18px; font-weight: 600; font-size: 14px; color: var(--tertiary); transition: .15s;
}
.lv-tab:hover { border-color: var(--green-line); color: var(--green); }
.lv-tab.on { background: var(--green); border-color: var(--green); color: #fff; }
.sen-box {
  background: var(--bg); border: 1px solid var(--line); border-radius: 14px;
  padding: 16px 18px; min-height: 90px; display: flex; gap: 12px; align-items: flex-start;
}
.sen-box .txt { flex: 1; }
.sen-box .en-sen { font-size: 1.05rem; font-weight: 600; line-height: 1.65; }
.sen-box .zh-sen { margin-top: 6px; color: var(--tertiary); line-height: 1.6; font-size: .95rem; }
.btn-play-sen {
  border: 1px solid var(--line); background: #fff; border-radius: 99px;
  width: 40px; height: 40px; font-size: 1rem; flex-shrink: 0; transition: .15s;
}
.btn-play-sen:hover { border-color: var(--green-line); }
.btn-play-sen.speaking { border-color: var(--green); background: var(--green-tint); }
.rate-row { display: flex; align-items: center; gap: 12px; justify-content: center; margin-top: 16px; }
.rate-row label { font-weight: 500; color: var(--tertiary); font-size: .9rem; }
input[type=range] { accent-color: var(--green); width: 200px; }
.rate-val { font-variant-numeric: tabular-nums; font-weight: 600; color: var(--green); width: 44px; font-size: .92rem; }
.reader-nav { display: flex; gap: 14px; justify-content: center; margin: 24px 0 8px; flex-wrap: wrap; }
.grid-toggle { text-align: center; margin-top: 6px; }
.word-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(96px, 1fr));
  gap: 10px; max-width: 640px; margin: 16px auto 0;
}
.word-grid button {
  border: 1px solid var(--line); background: #fff; border-radius: 12px; padding: 8px 4px;
  font-weight: 600; font-size: .82rem; transition: .12s;
}
.word-grid button:hover { border-color: var(--green-line); }
.word-grid button.cur { border-color: var(--green); background: var(--green-tint); color: var(--green); }
.word-grid button .em img { width: 34px; height: 34px; object-fit: cover; border-radius: 6px; vertical-align: middle; }

/* ---------- 对话场景 ---------- */
.scene-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 18px; }
.dlg { display: flex; flex-direction: column; gap: 12px; margin-top: 24px; max-width: 720px; margin-inline: auto; }
.bubble {
  max-width: 82%; background: var(--card); border: 1px solid var(--line);
  border-radius: 16px; padding: 13px 48px 13px 18px; box-shadow: var(--shadow); position: relative;
}
.bubble .who { font-size: .78rem; font-weight: 600; color: var(--green); margin-bottom: 4px; }
.bubble .en { font-weight: 600; line-height: 1.55; }
.bubble .zh { color: var(--tertiary); margin-top: 4px; font-size: .92rem; line-height: 1.55; }
.bubble .mini-play {
  position: absolute; right: 12px; top: 12px; border: 1px solid var(--line); background: #fff;
  border-radius: 99px; width: 34px; height: 34px; font-size: .9rem; transition: .15s;
}
.bubble .mini-play:hover { border-color: var(--green-line); }
.bubble .mini-play.speaking { border-color: var(--green); background: var(--green-tint); }
.bubble.me { align-self: flex-end; background: var(--green-tint); border-color: var(--green-line); }
.bubble.me .who { color: var(--green); }

/* ---------- 游戏百科 ---------- */
.article { max-width: 680px; margin: 0 auto; }
.article h2 { text-align: center; margin-bottom: 6px; letter-spacing: -.03em; }
.article .topic { text-align: center; color: var(--tertiary); margin-bottom: 20px; }
.para {
  background: var(--card); border: 1px solid var(--line); border-radius: 14px;
  padding: 16px 18px; margin-bottom: 12px; display: flex; gap: 12px; align-items: flex-start;
}
.para .txt { flex: 1; line-height: 1.75; }
.para .en { font-weight: 600; }
.para .zh { color: var(--tertiary); margin-top: 6px; font-size: .94rem; }
.group-head { display: flex; align-items: center; gap: 12px; margin: 34px 0 14px; }
.group-cover {
  width: 72px; height: 60px; object-fit: cover; border-radius: 12px;
  border: 1px solid var(--line); box-shadow: var(--shadow); flex: none;
}
.group-title { margin: 0; font-size: 1.2rem; letter-spacing: -.02em; font-weight: 700; }
.group-title small { color: var(--quiet); font-weight: 500; margin-left: 8px; font-size: .85rem; }
.detail-banner {
  display: block; width: 100%; max-width: 680px; height: 230px; object-fit: cover;
  margin: 14px auto 6px; border-radius: 16px; border: 1px solid var(--line);
  box-shadow: var(--shadow);
}
.article .detail-banner { margin-bottom: 16px; }
.article-meta { display: flex; gap: 8px; justify-content: center; align-items: center; flex-wrap: wrap; margin-bottom: 12px; }
.badge.lvb0 { background: #e8f1f8; color: #2a6f9e; border-color: #c8ddef; }
.badge.lvb1 { background: #faf3e0; color: var(--gold); border-color: #ecdcae; }
.badge.lvb2 { background: #fbe9e9; color: #a03a3a; border-color: #f0c8c8; }

/* ---------- 首页 · 主题自动循环滚动 ---------- */
.theme-rail-wrap { margin: 28px 0 8px; overflow: hidden; }
.theme-rail {
  display: flex; width: max-content;
  animation: rail-loop 45s linear infinite;
}
.theme-rail:hover { animation-play-state: paused; }
.rail-seg { display: flex; gap: 16px; padding-right: 16px; }
@keyframes rail-loop { from { transform: translateX(0); } to { transform: translateX(-50%); } }
.theme-card {
  flex: 0 0 200px; background: #fff;
  border: 1px solid var(--line); border-radius: 16px; overflow: hidden;
  box-shadow: var(--shadow); transition: .18s; text-decoration: none;
}
.theme-card:hover { border-color: var(--green-line); transform: translateY(-4px); box-shadow: 0 10px 26px rgba(58, 128, 90, .16); }
.tc-cover { position: relative; aspect-ratio: 4 / 3; overflow: hidden; background: #f2f5f2; }
.tc-cover img { width: 100%; height: 100%; object-fit: cover; display: block; transition: .3s; }
.theme-card:hover .tc-cover img { transform: scale(1.06); }
.tc-name {
  padding: 10px 12px 12px; font-weight: 700; font-size: 14.5px; color: var(--secondary);
  text-align: center; white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.theme-card:hover .tc-name { color: var(--green); }
@media (max-width: 720px) {
  .theme-card { flex-basis: 158px; }
}

/* ---------- 页脚 ---------- */
.footer {
  text-align: center; padding: 36px 16px 44px; color: var(--quiet); font-size: .86rem;
  border-top: 1px solid var(--line); margin-top: 40px; line-height: 1.9;
}
.footer b { color: var(--secondary); font-weight: 700; }
.about { max-width: 860px; margin: 0 auto 22px; text-align: center; }
.about-logo { width: min(420px, 82%); height: auto; display: block; margin: 0 auto 10px; }
.about-txt { text-align: center; }
.about-head { font-size: 1.15rem; letter-spacing: -.02em; color: var(--secondary); margin: 0 0 8px; }
.about-text { line-height: 2; margin: 0 0 6px; }
.nb { white-space: nowrap; }
.mob-only { display: none; }
@media (max-width: 899px) {
  .desk-only { display: none; }
  .mob-only { display: inline; }
}
.about-slogan { font-weight: 700; color: var(--green-dark); margin: 0 0 6px; }
.foot-meta { font-size: .8rem; }
@media (max-width: 899px) {
  /* 手机/平板：去图、去标题、去 slogan，只保留介绍正文 */
  .about-logo, .about-head, .about-slogan { display: none; }
  .about-text { line-height: 1.9; margin-bottom: 6px; }
}
@media (min-width: 900px) {
  /* PC：图片在左、文字在右 */
  .about { display: flex; align-items: center; gap: 64px; text-align: left; }
  .about-logo { width: 240px; flex: none; margin: 0; }
  .about-txt { flex: 1; text-align: left; }
  .about-text br { display: none; }
}

/* ---------- 登录弹窗 ---------- */
.modal-mask {
  position: fixed; inset: 0; background: rgb(0 0 0 / .4); z-index: 90;
  display: none; align-items: center; justify-content: center;
}
.modal-mask.on { display: flex; }
.modal {
  width: min(380px, 90vw); background: #fff; border-radius: 20px; padding: 30px;
  text-align: center; position: relative; box-shadow: var(--shadow-lg);
}
.modal h3 { margin-bottom: 8px; letter-spacing: -.02em; }
.modal p { color: var(--tertiary); line-height: 1.7; font-size: .94rem; }
.modal .close {
  position: absolute; right: 14px; top: 14px; border: 1px solid var(--line);
  background: #fff; border-radius: 99px; width: 34px; height: 34px; font-weight: 600;
}
.modal .demo-tabs { display: flex; gap: 8px; justify-content: center; margin: 18px 0; background: var(--bg); border-radius: 99px; padding: 4px; }
.modal .demo-tabs button { flex: 1; padding: 10px 0; border-radius: 99px; border: 0; background: transparent; font-weight: 600; color: var(--tertiary); }
.modal .demo-tabs button.on { background: var(--green); color: #fff; }
.modal .fake-input {
  border: 1px solid var(--line); border-radius: 12px; padding: 12px 16px; margin-bottom: 10px;
  color: var(--quiet); font-size: .92rem; text-align: left; user-select: none;
}
.modal .btn.primary { width: 100%; justify-content: center; }

/* ---------- 其他 ---------- */
.backlink { font-weight: 600; color: var(--tertiary); display: inline-block; margin-bottom: 14px; font-size: 14px; transition: color .15s; }
.backlink:hover { color: var(--green); }
.empty-tip { text-align: center; color: var(--quiet); padding: 30px 0; font-weight: 500; }

/* ---------- 中文开关 ---------- */
body.zh-off .zh, body.zh-off .zh-sen { display: none; }
.zh-toggle { white-space: nowrap; }
.article-meta .zh-toggle { margin-left: 6px; }

/* ---------- 像素图（保留兼容类） ---------- */
.pix {
  display: flex; align-items: center; justify-content: center;
  border-radius: 12px; background: var(--bg); border: 1px solid var(--line);
  font-size: 4rem; line-height: 1;
}
.f-card .pix-img, .pix-img {
  width: 140px; height: 140px; object-fit: cover; border-radius: 12px;
  background: var(--bg); border: 1px solid var(--line);
}

/* ---------- 手机适配 ---------- */
@media (max-width: 640px) {
  .topbar { height: 64px; gap: 10px; padding: 0 14px; }
  .nav { display: none; }
  .nav-burger { display: flex; }
  .btn-login { padding: 9px 14px; font-size: 13px; }
  .brand .brand-logo { height: 36px; }

  .view { padding: 22px 14px 60px; }
  .hero { padding-top: 14px; }
  .section-title { margin-top: 48px; }

  .universe { height: 360px; }
  .wall { top: 40px; }
  .wall-tile { width: 104px; height: 86px; }

  .cat-grid, .scene-grid { grid-template-columns: repeat(2, 1fr); gap: 10px; }
  .cat-cover { height: 96px; }
  .cat-body { padding: 10px 12px 12px; }
  .cat-body h4 { font-size: .95rem; }
  .cat-body p { font-size: .78rem; }
  .mod-grid { grid-template-columns: 1fr; gap: 14px; }

  .btn { padding: 9px 14px; font-size: 13px; }
  .btn.primary { padding: 11px 20px; }
  .reader-top { gap: 8px; }
  .reader-nav { gap: 10px; }
  .word-card { padding: 20px 16px 18px; }
  .card-img { width: 170px; height: 170px; }
  .word-head .en { font-size: 1.6rem; }
  .sen-box { padding: 12px; }
  .rate-row { gap: 8px; }
  .rate-row input[type=range] { width: 140px; }
  .word-grid { grid-template-columns: repeat(auto-fill, minmax(78px, 1fr)); }

  .bubble { max-width: 94%; padding: 11px 46px 11px 14px; }
  .para { padding: 12px; }
}

/* ---------- 趣挑战 ---------- */
.cat-quiz-btn {
  position: absolute; top: 10px; right: 10px; z-index: 2;
  border: 0; border-radius: 10px; padding: 6px 12px;
  font-size: 12.5px; font-weight: 700; color: #fff;
  background: linear-gradient(120deg, #ff8a3d, #ff5470, #b44dff);
  box-shadow: 0 3px 10px rgb(255 84 112 / .35);
  cursor: pointer; transition: transform .15s, box-shadow .15s;
}
.cat-quiz-btn:hover { transform: translateY(-2px) scale(1.05); box-shadow: 0 6px 16px rgb(255 84 112 / .5); }
.quiz-hero {
  position: relative; border-radius: var(--radius); overflow: hidden;
  box-shadow: var(--shadow-lg); margin: 18px 0 20px;
}
.quiz-hero img { display: block; width: 100%; height: clamp(180px, 32vw, 320px); object-fit: cover; }
.quiz-hero-mask {
  position: absolute; inset: auto 0 0 0; padding: 34px 22px 16px;
  background: linear-gradient(transparent, rgb(0 0 0 / .62)); color: #fff;
}
.quiz-hero-mask h3 { font-size: clamp(17px, 2.6vw, 24px); font-weight: 800; text-shadow: 0 2px 8px rgb(0 0 0 / .5); }
.quiz-hero-mask p { font-size: 13.5px; opacity: .92; margin-top: 4px; }
.quiz-rules { display: grid; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); gap: 10px; }
.rule-item {
  display: flex; align-items: center; gap: 10px; background: var(--card);
  border: 1px solid var(--line); border-radius: 12px; padding: 12px 14px;
  font-size: 14px; color: var(--secondary); box-shadow: var(--shadow);
}
.rule-item b {
  flex: none; width: 26px; height: 26px; border-radius: 8px; display: grid; place-items: center;
  background: var(--green-tint); color: var(--green); font-size: 14px;
}
.quiz-stage { max-width: 640px; margin: 0 auto; }
.quiz-top { display: flex; justify-content: space-between; align-items: center; margin-bottom: 14px; font-size: 14px; color: var(--tertiary); }
.quiz-score b { color: var(--green); font-size: 18px; }
.qz-streak { font-style: normal; margin-left: 10px; color: #ff5470; font-weight: 700; font-size: 13px; }
.qz-cardbox {
  position: relative; display: grid; place-items: center; min-height: 240px;
  background: linear-gradient(160deg, #eefaf4, #f6f1e6); border-radius: var(--radius);
  border: 1px solid var(--line); overflow: hidden;
}
.qz-card {
  width: 190px; height: 190px; border-radius: 14px; background: #fff;
  border: 4px solid #c9a24b; box-shadow: var(--shadow-lg); overflow: hidden;
  display: grid; place-items: center; transition: transform .12s;
}
.qz-card .qz-img { width: 100%; height: 100%; object-fit: cover; }
.qz-timer { height: 8px; border-radius: 99px; background: var(--line); margin-top: 14px; overflow: hidden; }
.qz-timer i { display: block; height: 100%; width: 100%; border-radius: 99px; background: linear-gradient(90deg, #2fbf71, #7ac943); transition: width .05s linear; }
.qz-timer i.danger { background: linear-gradient(90deg, #ff5470, #ff8a3d); }
.qz-opts { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; margin-top: 18px; }
.qz-opt {
  border: 2px solid var(--line); border-radius: 14px; background: var(--card);
  padding: 14px 8px; text-align: center; cursor: pointer; transition: all .15s;
  box-shadow: var(--shadow); font-family: inherit; color: var(--ink);
}
.qz-opt:hover:not(:disabled) { border-color: var(--green-line); transform: translateY(-3px); }
.qz-opt .qz-word { display: block; font-size: 19px; font-weight: 800; }
.qz-opt small { display: block; margin-top: 3px; color: var(--quiet); font-size: 12px; }
.qz-opt.right { border-color: #2fbf71; background: rgb(47 191 113 / .1); }
.qz-opt.wrong { border-color: #ff5470; background: rgb(255 84 112 / .08); animation: qzShake .4s; }
.qz-sound { margin: 16px auto 0; display: block; }
.qz-boy {
  position: absolute; bottom: 8%; width: 86px; z-index: 3; pointer-events: none;
  animation: qzLeap .5s cubic-bezier(.2,.9,.3,1.2) both;
}
.qz-boy:nth-of-type(2) { animation-delay: .1s; width: 100px; }
.qz-boy:nth-of-type(3) { animation-delay: .2s; width: 78px; }
.smashing .smash-target { animation: qzSmashCard .55s .45s cubic-bezier(.6,0,.9,.4) forwards; }
.qz-shards { position: absolute; inset: 0; z-index: 4; pointer-events: none; }
.qz-shards i {
  position: absolute; left: 50%; top: 46%; width: 16px; height: 16px; border-radius: 3px;
  opacity: 0; animation: qzShard .9s .5s cubic-bezier(.15,.7,.4,1) forwards;
  box-shadow: inset -3px -3px 0 rgb(0 0 0 / .18);
}
.qz-pop {
  position: absolute; left: 50%; top: 18%; transform: translateX(-50%); z-index: 5;
  font-size: 26px; font-weight: 900; color: #fff; white-space: nowrap;
  background: linear-gradient(120deg, #ffb800, #ff5470); padding: 8px 22px; border-radius: 99px;
  box-shadow: 0 8px 24px rgb(255 84 112 / .45);
  animation: qzPop .5s .55s cubic-bezier(.2,1.4,.4,1) both;
  text-shadow: 0 2px 6px rgb(0 0 0 / .25);
}
.qz-pop.miss { background: linear-gradient(120deg, #64748b, #334155); animation-delay: .05s; font-size: 18px; }
.qz-cardbox.shake { animation: qzShake .45s; }
.quiz-result { text-align: center; background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow-lg); padding: 40px 24px; margin-top: 10px; }
.qz-medal { font-size: 56px; animation: qzMedalPop .5s .1s cubic-bezier(.2,1.4,.4,1) both; }
@keyframes qzMedalPop { from { transform: scale(.3); opacity: 0; } to { transform: scale(1); opacity: 1; } }
.quiz-result h3 { font-size: 24px; margin: 10px 0 6px; }
.qz-final { font-size: 17px; color: var(--secondary); }
.qz-final b { color: var(--green); font-size: 26px; }
.qz-best { font-size: 13.5px; color: var(--quiet); margin-top: 4px; }
.qz-actions { display: flex; gap: 12px; justify-content: center; margin-top: 22px; }
@keyframes qzShake { 0%,100% { transform: translateX(0); } 20% { transform: translateX(-8px); } 40% { transform: translateX(8px); } 60% { transform: translateX(-6px); } 80% { transform: translateX(6px); } }
@keyframes qzLeap { from { transform: translateY(130%) rotate(-14deg); opacity: 0; } to { transform: translateY(0) rotate(0); opacity: 1; } }
@keyframes qzSmashCard {
  30% { transform: rotate(-4deg) scale(1.06); }
  100% { transform: rotate(8deg) scale(.1); opacity: 0; }
}
@keyframes qzShard {
  0% { transform: translate(0, 0) rotate(0); opacity: 1; }
  100% { transform: translate(var(--dx), var(--dy)) rotate(var(--rz)); opacity: 0; }
}
@keyframes qzPop { from { transform: translateX(-50%) scale(.3); opacity: 0; } to { transform: translateX(-50%) scale(1); opacity: 1; } }
@media (max-width: 640px) {
  .qz-opts { grid-template-columns: 1fr; }
  .qz-card { width: 150px; height: 150px; }
  .qz-boy { width: 64px; }
  .qz-boy:nth-of-type(2) { width: 74px; }
  .qz-boy:nth-of-type(3) { width: 58px; }
}

/* ---------- 悬浮伙伴 Steve ---------- */
#steve {
  position: fixed; z-index: 60; cursor: grab;
  touch-action: none; user-select: none; -webkit-user-drag: none;
  perspective: 800px;
}
#steve.steve-off { display: none; }
#steve::before {
  content: ""; position: absolute; left: 50%; bottom: -2px; z-index: -1;
  width: 92px; height: 18px; transform: translateX(-50%);
  background: radial-gradient(ellipse at center, rgb(0 0 0 / .3), rgb(0 0 0 / 0) 68%);
  animation: stvShadow 2.4s ease-in-out infinite;
}
@keyframes stvShadow { 0%,100% { transform: translateX(-50%) scale(1); opacity: .9; } 50% { transform: translateX(-50%) scale(.8); opacity: .55; } }
#steve:active { cursor: grabbing; }
#steve img {
  display: block; height: 132px; pointer-events: none;
}
#steve-idle { transform-origin: 50% 100%; transform-style: preserve-3d; animation: stvBob 2.4s ease-in-out infinite; }
@keyframes stvBob {
  0%,100% { transform: translateY(0); }
  50% { transform: translateY(-4px); }
}
#steve.speaking #steve-idle { animation-duration: .55s; }
#steve.dragging #steve-idle { animation: none; }
#steve.dragging #steve-img { animation: stvSway .4s ease-in-out infinite alternate !important; }
@keyframes stvSway { from { transform: rotate(-6deg); } to { transform: rotate(6deg); } }
#steve-img.act-jump    { animation: stvJump .7s ease-out !important; }
@keyframes stvJump { 0% { transform: translateY(0); } 40% { transform: translateY(-46px) scaleY(1.04); } 80% { transform: translateY(0) scaleY(.96); } 100% { transform: translateY(0) scaleY(1); } }
#steve-img.act-spin    { animation: stvSpin .9s ease-in-out !important; }
@keyframes stvSpin { from { transform: rotateY(0); } to { transform: rotateY(360deg); } }
#steve-img.act-dance   { animation: stvDance 1.6s ease-in-out !important; }
@keyframes stvDance { 0%,100% { transform: rotate(0) translateY(0); } 15% { transform: rotate(-8deg) translateY(-12px); } 30% { transform: rotate(8deg) translateY(0); } 45% { transform: rotate(-8deg) translateY(-12px); } 60% { transform: rotate(8deg) translateY(0); } 75% { transform: rotate(-6deg) translateY(-8px); } 90% { transform: rotate(6deg) translateY(0); } }
#steve-img.act-bow     { animation: stvBow 1.2s ease-in-out !important; }
@keyframes stvBow { 0%,100% { transform: rotateX(0); } 40%,60% { transform: rotateX(26deg) scaleY(.95); } }
#steve-img.act-shake   { animation: stvShake .9s ease-in-out !important; }
@keyframes stvShake { 0%,100% { transform: rotate(0); } 20% { transform: rotate(-9deg); } 40% { transform: rotate(9deg); } 60% { transform: rotate(-6deg); } 80% { transform: rotate(4deg); } }
#steve-img.act-startle { animation: stvStartle .9s ease-out !important; }
@keyframes stvStartle { 0% { transform: translateY(0) rotate(0); } 30% { transform: translateY(-52px) rotate(-6deg); } 60% { transform: translateY(-52px) rotate(6deg); } 100% { transform: translateY(0) rotate(0); } }
#steve-bubble {
  position: fixed; z-index: 61; max-width: min(300px, 74vw);
  padding: 9px 14px; text-align: center; pointer-events: none;
  background: #fff; border: 2px solid var(--green-line); border-radius: 12px;
  box-shadow: var(--shadow-lg); transition: opacity .3s;
}
#steve-bubble::after {
  content: ""; position: absolute; bottom: -8px; left: 50%; margin-left: -6px;
  width: 0; height: 0; border-left: 6px solid transparent; border-right: 6px solid transparent;
  border-top: 8px solid #fff;
}
#steve-bubble.hidden { opacity: 0; }
#steve-bubble-en { display: block; font-size: 14.5px; font-weight: 700; color: var(--ink); }
#steve-bubble-zh { display: block; margin-top: 2px; font-size: 12px; color: var(--tertiary); }
@media (max-width: 640px) { #steve img { height: 96px; } }

/* ---------- 继续学习 & 收藏 ---------- */
.resume-bar {
  display: flex; align-items: center; gap: 14px; max-width: 640px; margin: 14px auto 26px;
  background: var(--card); border: 1px solid var(--line); border-radius: 16px;
  padding: 12px 16px; box-shadow: var(--shadow); transition: .18s; color: inherit; text-decoration: none;
}
.resume-bar:hover { border-color: var(--green-line); transform: translateY(-2px); box-shadow: var(--shadow-lg); }
.resume-bar img { width: 54px; height: 54px; border-radius: 12px; object-fit: cover; background: #fff; border: 1px solid var(--line); flex: none; }
.resume-info { flex: 1; min-width: 0; display: grid; gap: 3px; }
.resume-info b { font-size: 14.5px; color: var(--ink); }
.resume-sub { font-size: 12.5px; color: var(--tertiary); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.resume-track { display: block; height: 5px; border-radius: 99px; background: var(--line); overflow: hidden; margin-top: 3px; }
.resume-track i { display: block; height: 100%; border-radius: 99px; background: linear-gradient(90deg, #2fbf71, #7ac943); }
.resume-go { flex: none; font-size: 13.5px; font-weight: 700; color: var(--green); }
.fav-star {
  position: absolute; top: 12px; right: 12px; z-index: 2;
  width: 40px; height: 40px; border-radius: 50%; border: 1px solid var(--line);
  background: rgb(255 255 255 / .85); backdrop-filter: blur(6px);
  font-size: 20px; line-height: 1; color: #c8cdd6; cursor: pointer;
  display: grid; place-items: center; transition: .18s;
  box-shadow: 0 2px 8px rgb(0 0 0 / .08);
}
.fav-star:hover { transform: scale(1.12) rotate(8deg); color: #ffb800; }
.fav-star.on { color: #ffb800; border-color: #ffd668; background: #fff7e0; text-shadow: 0 1px 3px rgb(255 184 0 / .4); }
.word-card { position: relative; }
.fav-entry {
  display: flex; align-items: center; gap: 12px; max-width: 640px; margin: 0 auto 16px;
  background: linear-gradient(120deg, #fff7e0, #fdf3ff); border: 1px solid #f2dfae;
  border-radius: 14px; padding: 10px 16px; text-decoration: none; color: inherit; transition: .18s;
}
.fav-entry:hover { transform: translateY(-2px); box-shadow: var(--shadow); }
.fav-entry-star { font-size: 22px; color: #ffb800; text-shadow: 0 1px 3px rgb(255 184 0 / .35); }
.fav-entry-txt { flex: 1; display: grid; }
.fav-entry-txt b { font-size: 14.5px; color: var(--ink); }
.fav-entry-txt small { font-size: 12px; color: var(--tertiary); }
.fav-count-pill {
  flex: none; min-width: 30px; height: 26px; padding: 0 9px; border-radius: 99px;
  background: #ffb800; color: #fff; font-size: 13px; font-weight: 800;
  display: grid; place-items: center; box-shadow: 0 2px 8px rgb(255 184 0 / .35);
}
.fav-head { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
h2 .fav-count {
  display: inline-grid; place-items: center; min-width: 30px; height: 26px; padding: 0 9px;
  font-size: 14px; color: #fff; background: #ffb800; border-radius: 99px; vertical-align: 4px;
}
.fav-card { position: relative; }
.fav-remove {
  position: absolute; top: 10px; right: 10px; z-index: 2;
  width: 32px; height: 32px; border-radius: 50%; border: 0; cursor: pointer;
  background: rgb(0 0 0 / .35); backdrop-filter: blur(6px); color: #ffb800; font-size: 16px;
  display: grid; place-items: center; transition: .15s;
}
.fav-remove:hover { background: rgb(255 84 112 / .8); color: #fff; transform: scale(1.1); }
.fav-empty { text-align: center; padding: 60px 20px; color: var(--tertiary); }
.fav-empty p { font-size: 16px; margin-bottom: 18px; }
@media (max-width: 640px) {
  .fav-star { width: 34px; height: 34px; font-size: 17px; top: 9px; right: 9px; }
  .resume-bar { padding: 10px 12px; gap: 10px; }
  .resume-bar img { width: 44px; height: 44px; }
}

/* ---------- 顶栏收藏入口 ---------- */
.btn-fav {
  position: relative; flex: none; display: grid; place-items: center;
  width: 42px; height: 42px; border-radius: 50%;
  border: 1px solid var(--line); background: #fff; color: #e6a700; font-size: 19px;
  transition: .15s; text-decoration: none;
  margin-left: auto; margin-right: 2px;
}
.btn-fav:hover { border-color: #ffd668; background: #fff7e0; transform: translateY(-1px); box-shadow: var(--shadow); }
.btn-fav.on { border-color: var(--green-line); color: var(--green); background: var(--green-tint); }
.fav-badge {
  position: absolute; top: -4px; right: -4px; min-width: 18px; height: 18px; padding: 0 4px;
  border-radius: 99px; background: #ffb800; color: #fff;
  font-size: 11px; font-weight: 800; line-height: 1; display: grid; place-items: center;
  border: 2px solid #fff; box-shadow: 0 1px 4px rgb(255 184 0 / .4);
}
.fav-badge.zero { display: none; }
@media (max-width: 640px) {
  .btn-fav { width: 36px; height: 36px; font-size: 16px; }
}

/* ---------- 收藏列表/卡片双视图 ---------- */
.fav-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 14px; }
.fav-grid .cat-cover { height: 110px; padding: 8px !important; background: #fff; }
.fav-grid .fav-img { width: 100%; height: 100%; object-fit: contain; image-rendering: pixelated; }
.fav-grid .cat-body { padding: 8px 10px 10px; }
.fav-grid .cat-body h4 { font-size: .92rem; }
.fav-grid .img-tag { font-size: 10.5px; top: 8px; left: 8px; padding: 2px 7px; }
.fav-switch { display: flex; border: 1px solid var(--line); border-radius: 99px; overflow: hidden; background: #fff; }
.fav-switch button {
  border: 0; background: transparent; padding: 8px 15px; font-size: 13px; font-weight: 600;
  color: var(--tertiary); cursor: pointer; transition: .15s; font-family: inherit;
}
.fav-switch button.on { background: var(--green); color: #fff; }
.fav-list { display: grid; gap: 8px; }
.fav-row {
  display: flex; align-items: center; gap: 14px; background: var(--card);
  border: 1px solid var(--line); border-radius: 14px; padding: 8px 14px; transition: .15s;
  box-shadow: var(--shadow); cursor: pointer;
}
.fav-row:hover { border-color: var(--green-line); transform: translateX(2px); }
.fav-row img { width: 46px; height: 46px; border-radius: 10px; object-fit: contain; background: #fff; border: 1px solid var(--line); flex: none; image-rendering: pixelated; }
.fr-word { font-size: 16px; font-weight: 800; min-width: 110px; }
.fr-zh { color: var(--secondary); font-size: 14px; flex: 1; }
.fr-cat { font-size: 12px; color: var(--quiet); background: var(--bg); border: 1px solid var(--line); border-radius: 99px; padding: 3px 10px; white-space: nowrap; }
.fr-go { flex: none; font-size: 13px; font-weight: 700; color: var(--green); text-decoration: none; white-space: nowrap; }
.fr-go:hover { text-decoration: underline; }
.fr-del {
  flex: none; width: 28px; height: 28px; border-radius: 50%; border: 1px solid var(--line);
  background: #fff; color: var(--quiet); font-size: 13px; cursor: pointer; transition: .15s;
  display: grid; place-items: center;
}
.fr-del:hover { border-color: #ff5470; color: #ff5470; background: rgb(255 84 112 / .06); }
@media (max-width: 640px) {
  .fav-grid { grid-template-columns: repeat(auto-fill, minmax(112px, 1fr)); gap: 10px; }
  .fav-grid .cat-cover { height: 92px; }
  .fav-row { gap: 10px; padding: 8px 10px; }
  .fav-row img { width: 40px; height: 40px; }
  .fr-word { min-width: 0; font-size: 14.5px; flex: 1; }
  .fr-zh { display: none; }
  .fr-cat { display: none; }
}

/* ---------- 百科：重点词 + 读懂了吗 ---------- */
.sec-head { font-size: 1.15rem; letter-spacing: -.02em; margin: 0 0 6px; }
.kw-section, .chk-section {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 18px 20px; margin-top: 18px; box-shadow: var(--shadow);
}
.sec-note { color: var(--quiet); font-size: .85rem; line-height: 1.6; margin-bottom: 12px; }
.kw-list { display: flex; flex-direction: column; gap: 10px; }
.kw-card {
  border: 1px solid var(--line); border-radius: 12px; overflow: hidden;
  cursor: pointer; transition: border-color .15s, background .15s; background: #fff;
}
.kw-card:hover { border-color: var(--green-line); }
.kw-card.open { border-color: var(--green-line); background: var(--green-tint); }
.kw-row { display: flex; align-items: center; gap: 10px; padding: 12px 14px; }
.kw-word { font-weight: 700; font-size: 1.05rem; letter-spacing: -.01em; flex: 1; }
.kw-arrow { color: var(--quiet); font-size: .8rem; transition: transform .18s; }
.kw-card.open .kw-arrow { transform: rotate(180deg); }
.kw-body { display: none; padding: 0 14px 14px; }
.kw-card.open .kw-body { display: block; }
.kw-zh { color: var(--green-dark); font-weight: 600; font-size: .95rem; margin-bottom: 10px; }
.kw-ex-label { font-size: .75rem; color: var(--quiet); font-weight: 700; margin-bottom: 4px; letter-spacing: .05em; }
.kw-ex { font-weight: 600; line-height: 1.65; display: flex; align-items: baseline; gap: 8px; flex-wrap: wrap; }
.kw-ex-zh { color: var(--tertiary); font-size: .9rem; margin-top: 5px; line-height: 1.6; }
.chk-q { font-weight: 700; font-size: 1.05rem; line-height: 1.65; display: flex; align-items: baseline; gap: 8px; flex-wrap: wrap; }
.chk-qzh { color: var(--tertiary); font-size: .9rem; margin: 5px 0 14px; }
.chk-reveal { border-color: var(--green-line); color: var(--green); font-weight: 700; }
.chk-a { display: none; margin-top: 14px; background: var(--green-tint); border: 1px dashed var(--green-line);
  border-radius: 12px; padding: 12px 14px; font-weight: 600; line-height: 1.65; align-items: baseline; gap: 8px; flex-wrap: wrap; }
.chk-a.show { display: flex; }
.chk-azh { display: none; color: var(--tertiary); font-size: .9rem; margin-top: 6px; }
.chk-a.show + .chk-azh { display: block; }
.mini-play {
  border: none; background: none; font-size: .95rem; padding: 2px 4px; line-height: 1;
  color: var(--green); border-radius: 8px; flex: none; transition: .15s;
}
.mini-play:hover { background: var(--green-tint); }
.mini-play.speaking { background: var(--green-tint); animation: micPulse 1s infinite; }
@keyframes micPulse { 50% { opacity: .55; } }
@media (max-width: 640px) {
  .kw-section, .chk-section { padding: 14px 14px; }
  .sec-note { font-size: .8rem; }
  .kw-row { padding: 11px 12px; }
  .kw-word { font-size: 1rem; }
  .kw-body { padding: 0 12px 12px; }
  .article h2 { font-size: 1.45rem; }
}
@media (min-width: 900px) {
  .kw-section, .chk-section { padding: 22px 26px; }
}

/* ---------- 百科阅读页：左右双栏布局 ---------- */
.rd-layout { max-width: 1100px; margin: 0 auto; }
.rd-head { display: block; margin-bottom: 14px; }
.rd-head h2 { text-align: left; margin-bottom: 4px; }
.rd-head .topic { text-align: left; margin-bottom: 10px; }
.rd-head .article-meta { justify-content: flex-start; margin-bottom: 0; }
.rd-cols { display: block; }
.rd-main .para { margin-bottom: 10px; }
.reader-nav { align-items: center; }
.rd-pos { color: var(--quiet); font-size: .9rem; font-weight: 600; }
@media (min-width: 900px) {
  .rd-head { display: flex; gap: 22px; align-items: stretch; }
  .rd-head .detail-banner { width: 380px; max-width: 380px; height: auto; min-height: 180px; margin: 0; flex: none; }
  .rd-head-txt { flex: 1; display: flex; flex-direction: column; justify-content: center; }
  .rd-cols { display: grid; grid-template-columns: minmax(0, 1.6fr) minmax(300px, 1fr); gap: 18px; align-items: start; }
  .rd-side { display: flex; flex-direction: column; gap: 14px; position: sticky; top: 90px; }
  .rd-side .kw-section, .rd-side .chk-section { margin-top: 0; padding: 16px 18px; }
  .rd-main { min-width: 0; }
}