/* ============ 基础 ============ */
:root{
  --red:#e8402f;
  --red-dark:#d33323;
  --line:#eee;
  --text:#222;
  --sub:#999;
  --bg-gray:#f4f5f6;
}
*{margin:0;padding:0;box-sizing:border-box;-webkit-tap-highlight-color:transparent;}
html,body{height:100%;}
body{
  font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  background:#e8e8e8;color:var(--text);
}
body.locked{overflow:hidden;}
button{font-family:inherit;}
img{max-width:100%;}
.app{
  position:relative;max-width:720px;margin:0 auto;height:100vh;height:100dvh;
  background:#fff;overflow:hidden;box-shadow:0 0 26px rgba(0,0,0,.14);
}
.icon-btn{
  background:none;border:0;color:#fff;width:42px;height:42px;flex:none;
  display:flex;align-items:center;justify-content:center;cursor:pointer;border-radius:8px;
}
.icon-btn:active{background:rgba(255,255,255,.18);}
.icon-btn svg{width:24px;height:24px;fill:currentColor;}
.icon-btn.dark{color:#444;}
.icon-btn.dark:active{background:rgba(0,0,0,.07);}

/* ============ 顶部导航栏 + 分类栏 ============ */
.page-feed{display:flex;flex-direction:column;height:100%;}
.topbar{
  flex:none;display:flex;align-items:center;justify-content:space-between;
  height:52px;padding:0 8px 0 16px;background:linear-gradient(90deg,var(--red),#f0503d);color:#fff;
}
.logo{
  font-size:23px;font-weight:800;letter-spacing:3px;color:#fff;
  text-shadow:0 1px 2px rgba(0,0,0,.12);user-select:none;
}
.tabs{
  flex:none;display:flex;align-items:stretch;gap:24px;padding:0 16px;height:44px;
  background:#fff;border-bottom:1px solid var(--line);overflow-x:auto;scrollbar-width:none;
}
.tabs::-webkit-scrollbar{display:none;}
.tab{
  position:relative;background:none;border:0;cursor:pointer;white-space:nowrap;
  font-size:16px;color:#555;display:flex;align-items:center;transition:color .15s;
}
.tab.active{color:var(--red);font-weight:700;font-size:18px;}
.tab.active::after{
  content:"";position:absolute;left:50%;transform:translateX(-50%);bottom:4px;
  width:26px;height:3px;border-radius:2px;background:var(--red);
}

/* ============ 资讯流列表 ============ */
.feed-scroll{flex:1;overflow-y:auto;overscroll-behavior:contain;background:#fff;}
.feed-list{display:none;}
.feed-list.active{display:block;}
.feed-item{
  display:flex;gap:12px;padding:14px 16px;border-bottom:1px solid #f3f3f3;cursor:pointer;
}
.feed-item:active{background:#fafafa;}
.fi-main{flex:1;min-width:0;display:flex;flex-direction:column;justify-content:space-between;}
.fi-title{
  font-size:17px;font-weight:600;line-height:1.42;color:#222;
  display:-webkit-box;-webkit-line-clamp:3;-webkit-box-orient:vertical;overflow:hidden;
}
.fi-meta{margin-top:10px;display:flex;align-items:center;gap:6px;font-size:12px;color:var(--sub);overflow:hidden;}
.fi-srctag{
  flex:none;font-size:10px;color:#fff;background:var(--red);border-radius:2px;
  padding:1px 3px;line-height:1.5;max-width:5em;overflow:hidden;white-space:nowrap;
}
.fi-time{flex:none;}
.fi-thumb{
  flex:none;width:116px;height:82px;border-radius:6px;overflow:hidden;background:#f1f2f3;position:relative;
}
.fi-thumb img{width:100%;height:100%;object-fit:cover;display:block;}
.fi-thumb.no-img::after{
  content:"暂无图片";position:absolute;inset:0;display:flex;align-items:center;justify-content:center;
  color:#c2c2c2;font-size:12px;
}
.feed-status{
  text-align:center;color:#aaa;font-size:13px;padding:16px 0 22px;cursor:default;
}
.feed-status.retry{color:var(--red);cursor:pointer;}
.feed-sentinel{height:1px;}
.feed-error{
  margin:60px 30px;text-align:center;color:#888;font-size:14px;line-height:2;
}
.feed-error button{
  margin-top:10px;background:var(--red);color:#fff;border:0;border-radius:20px;
  padding:8px 30px;font-size:14px;cursor:pointer;
}

/* 骨架屏 */
.sk-row{display:flex;gap:12px;padding:14px 16px;border-bottom:1px solid #f3f3f3;}
.sk-col{flex:1;}
.sk-thumb{flex:none;width:116px;height:82px;border-radius:6px;}
.sk-line{
  background:linear-gradient(90deg,#f1f1f1 25%,#e8e8e8 37%,#f1f1f1 63%);
  background-size:400% 100%;animation:sk 1.2s ease infinite;border-radius:4px;
}
@keyframes sk{0%{background-position:100% 0}100%{background-position:0 0}}

/* ============ 文章内容层（右侧滑入） ============ */
.layer-outer{
  position:fixed;inset:0;z-index:100;display:flex;justify-content:center;pointer-events:none;
}
.article-layer{
  position:relative;width:100%;max-width:720px;height:100%;background:#fff;
  display:flex;flex-direction:column;
  transform:translateX(110%);visibility:hidden;
  transition:transform .3s ease,visibility 0s linear .3s;
  box-shadow:-10px 0 30px rgba(0,0,0,.16);
}
.article-layer.open{transform:translateX(0);visibility:visible;pointer-events:auto;transition:transform .3s ease;}
.article-topbar{
  flex:none;display:flex;align-items:center;height:48px;padding:0 8px;
  border-bottom:1px solid var(--line);background:#fff;position:relative;z-index:2;
}
.ab-title{
  flex:1;text-align:center;font-size:16px;font-weight:600;color:#333;
  overflow:hidden;text-overflow:ellipsis;white-space:nowrap;
}
.article-scroll{flex:1;overflow-y:auto;overscroll-behavior:contain;-webkit-overflow-scrolling:touch;}

/* 栈内单篇文章 */
.feed-article{padding:20px 18px 26px;border-bottom:12px solid var(--bg-gray);}
.feed-article.preloaded{display:none;}/* 预加载的下一篇：阅读完上一篇后转为显示 */
.a-title{font-size:22px;line-height:1.45;font-weight:700;color:#1a1a1a;}
.a-meta{margin-top:12px;display:flex;align-items:center;gap:7px;font-size:13px;color:var(--sub);}
.a-srctag{
  font-size:11px;color:#fff;background:var(--red);border-radius:2px;
  padding:1px 4px;max-width:6em;overflow:hidden;white-space:nowrap;
}
.a-body{margin-top:16px;font-size:17px;line-height:1.85;color:#333;word-break:break-word;}
.a-body p{margin:0 0 18px;}
.a-body h1,.a-body h2,.a-body h3{font-size:19px;margin:22px 0 14px;}
.a-body img{display:block;height:auto;margin:8px auto 16px;border-radius:4px;}
.a-body img.img-broken{display:none;}
.a-body a{color:var(--red-dark);}
.a-body blockquote{margin:0 0 18px;padding:10px 14px;border-left:3px solid #ddd;color:#777;background:#fafafa;}
.a-body .sk-line{height:15px;margin-bottom:14px;}
.a-divider{display:flex;align-items:center;gap:10px;margin:2px -18px 20px;color:#bbb;font-size:12px;}
.a-divider::before,.a-divider::after{content:"";flex:1;height:1px;background:#ececec;}
.a-fail{
  background:#fff8f0;border:1px solid #ffe0b8;border-radius:8px;padding:14px;
  font-size:14px;line-height:1.8;color:#8a6d3b;margin-top:6px;
}
.a-fail .a-fail-btn{
  display:inline-block;background:var(--red);color:#fff;border:0;border-radius:16px;
  padding:6px 22px;font-size:13px;cursor:pointer;margin-right:10px;
}
.a-fail a{color:var(--red-dark);word-break:break-all;}
.stack-end{text-align:center;color:#bbb;font-size:13px;padding:22px 0 34px;}

/* ============ 历史记录层（文章层之上） ============ */
.history-layer{position:fixed;inset:0;z-index:200;display:flex;justify-content:center;visibility:hidden;transition:visibility 0s linear .28s;}
.history-layer.open{visibility:visible;transition:none;}
.mask{position:absolute;inset:0;background:rgba(0,0,0,.45);opacity:0;transition:opacity .28s;}
.history-layer.open .mask{opacity:1;}
.history-panel{
  position:absolute;bottom:0;width:100%;max-width:720px;max-height:76%;
  background:#fff;border-radius:16px 16px 0 0;display:flex;flex-direction:column;
  transform:translateY(100%);transition:transform .3s ease;box-shadow:0 -6px 30px rgba(0,0,0,.2);
}
.history-layer.open .history-panel{transform:translateY(0);}
.hp-head{
  flex:none;display:flex;align-items:center;justify-content:space-between;
  padding:6px 8px 6px 18px;border-bottom:1px solid var(--line);
}
.hp-tit{font-size:16px;font-weight:700;}
.hp-ops{display:flex;align-items:center;gap:2px;}
.hp-clear{
  background:none;border:1px solid #ddd;color:#888;border-radius:14px;
  font-size:12px;padding:4px 12px;cursor:pointer;
}
.hp-clear:active{background:#f2f2f2;}
.hp-list{flex:1;overflow-y:auto;padding-bottom:env(safe-area-inset-bottom);}
.hp-item{display:flex;padding:12px 16px;border-bottom:1px solid #f6f6f6;cursor:pointer;}
.hp-item:active{background:#fafafa;}
.hp-main{flex:1;min-width:0;}
.hp-title{
  font-size:15px;font-weight:600;line-height:1.45;color:#333;
  display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;
}
.hp-meta{margin-top:7px;display:flex;align-items:center;gap:6px;font-size:12px;color:var(--sub);}
.hp-empty{text-align:center;color:#aaa;font-size:14px;padding:70px 0;}

.topbar-ops{display:flex;align-items:center;}

/* ============ 登录/注册层 ============ */
.auth-layer{
  position:fixed;inset:0;z-index:400;display:none;align-items:center;justify-content:center;
  background:linear-gradient(160deg,#e8402f,#f0654f 60%,#f2836f);padding:20px;
}
.auth-layer.open{display:flex;}
.auth-card{
  width:100%;max-width:340px;background:#fff;border-radius:14px;padding:26px 22px 22px;
  box-shadow:0 12px 40px rgba(0,0,0,.25);
}
.auth-logo{text-align:center;font-size:30px;font-weight:800;letter-spacing:4px;color:var(--red);}
.auth-sub{text-align:center;font-size:12px;color:#aaa;margin:6px 0 18px;}
.auth-tabs{display:flex;border-bottom:1px solid var(--line);margin-bottom:18px;}
.auth-tab{
  flex:1;background:none;border:0;font-size:15px;color:#888;padding:10px 0;cursor:pointer;
  position:relative;
}
.auth-tab.active{color:var(--red);font-weight:700;}
.auth-tab.active::after{
  content:"";position:absolute;left:50%;transform:translateX(-50%);bottom:-1px;
  width:32px;height:3px;border-radius:2px;background:var(--red);
}
.field-label{display:block;font-size:12px;color:#888;margin:4px 0 4px;}
.auth-input{
  width:100%;border:1px solid #ddd;border-radius:8px;padding:11px 12px;font-size:15px;
  margin-bottom:12px;outline:none;
}
.auth-input:focus{border-color:var(--red);}
.auth-err{color:var(--red);font-size:13px;min-height:18px;margin:-2px 0 6px;}
.auth-submit{
  width:100%;background:var(--red);color:#fff;border:0;border-radius:8px;
  padding:12px 0;font-size:16px;font-weight:600;cursor:pointer;
}
.auth-submit:disabled{opacity:.6;}

/* ============ 设置页 ============ */
.settings-outer{position:fixed;inset:0;z-index:90;display:flex;justify-content:center;pointer-events:none;}
.settings-layer{
  position:relative;width:100%;max-width:720px;height:100%;background:#fff;
  display:flex;flex-direction:column;transform:translateX(110%);visibility:hidden;
  transition:transform .3s ease,visibility 0s linear .3s;box-shadow:-10px 0 30px rgba(0,0,0,.16);
}
.settings-layer.open{transform:translateX(0);visibility:visible;pointer-events:auto;transition:transform .3s ease;}
.settings-body{flex:1;overflow-y:auto;padding:16px 18px 40px;}
.ab-pad{width:42px;flex:none;}
.set-user{font-size:14px;color:#666;background:#fafafa;border:1px solid #f0f0f0;border-radius:8px;padding:10px 12px;margin-bottom:6px;}
.set-sec{font-size:13px;color:#999;margin:20px 0 10px;}
.set-input{
  width:100%;border:1px solid #ddd;border-radius:8px;padding:10px 12px;font-size:14px;
  margin-bottom:10px;outline:none;
}
.set-input:focus{border-color:var(--red);}
.set-btn{
  background:var(--red);color:#fff;border:0;border-radius:8px;padding:9px 22px;
  font-size:14px;cursor:pointer;
}
.set-btn:active{opacity:.85;}
.set-tip{font-size:13px;color:#bbb;background:#fafafa;border-radius:8px;padding:12px;}
.logout-btn{
  width:100%;margin-top:34px;background:#fff;border:1px solid var(--red);color:var(--red);
  border-radius:8px;padding:11px 0;font-size:15px;font-weight:600;cursor:pointer;
}
.logout-btn:active{background:#fdeceb;}

/* ============ 记忆题 ============ */
.btn-ghosted{visibility:hidden;}
.a-quiz-area{padding:6px 0 14px;text-align:center;}
.a-quiz-area .quiz-box{text-align:left;}/* 题目移入文章后居左 */
.quiz-start-btn{
  width:86%;background:var(--red);color:#fff;border:0;border-radius:24px;
  padding:13px 0;font-size:16px;font-weight:700;letter-spacing:2px;cursor:pointer;
  box-shadow:0 4px 14px rgba(232,64,47,.3);
}
.quiz-start-btn:disabled{background:#ccc;box-shadow:none;cursor:default;}
.quiz-layer{
  position:fixed;inset:0;z-index:150;background:#fff;display:none;flex-direction:column;
}
.quiz-layer.open{display:flex;}
.quiz-head{
  flex:none;display:flex;align-items:center;justify-content:space-between;
  background:linear-gradient(90deg,var(--red),#f0503d);color:#fff;padding:12px 16px;
}
.qh-tit{font-size:17px;font-weight:700;letter-spacing:2px;}
.qh-close{background:rgba(255,255,255,.18);border:0;color:#fff;border-radius:16px;padding:7px 14px;font-size:13px;cursor:pointer;}
.qh-close:active{background:rgba(255,255,255,.3);}
.quiz-body{flex:1;overflow-y:auto;padding:20px 18px 40px;-webkit-overflow-scrolling:touch;}
.quiz-box{max-width:640px;margin:0 auto;}
.q-item{margin-bottom:26px;}
.q-tit{font-size:16px;line-height:2.1;color:#222;}
.q-no{color:var(--red);font-weight:700;margin-right:2px;}
.q-blank{
  display:inline-block;width:96px;border:0;border-bottom:2px solid #bbb;background:#fafafa;
  text-align:center;font-size:15px;padding:3px 6px;outline:none;border-radius:6px 6px 0 0;
  margin:0 3px;
}
.q-blank:focus{border-bottom-color:var(--red);background:#fff;}
.q-blank.q-right{border-bottom-color:#2eaf64;background:#f0faf5;}
.q-blank.q-wrong{border-bottom-color:var(--red);background:#fdf1f0;}
.q-check{margin-top:8px;font-size:13px;}
.q-check.q-ok{color:#2eaf64;}
.q-check.q-bad{color:var(--red);}
.q-order-row{
  display:flex;align-items:center;gap:10px;background:#fafafa;border:1.5px solid #eee;
  border-radius:10px;padding:11px 12px;margin:0 0 10px;
}
.q-order-row.q-right{border-color:#2eaf64;background:#f0faf5;}
.q-order-row.q-wrong{border-color:var(--red);background:#fdf1f0;}
.q-order-txt{flex:1;font-size:14px;line-height:1.6;color:#333;}
.q-order-ops{display:flex;gap:6px;flex:none;}
.q-order-ops button{
  width:32px;height:32px;border:1px solid #ddd;background:#fff;border-radius:8px;
  font-size:15px;color:#555;cursor:pointer;
}
.q-order-ops button:disabled{opacity:.45;cursor:default;}
.qb-actions{margin-top:26px;text-align:center;}
.qb-submit{
  width:70%;background:var(--red);color:#fff;border:0;border-radius:24px;
  padding:12px 0;font-size:16px;font-weight:700;cursor:pointer;
}
.qb-submit:disabled{background:#ccc;cursor:default;}
.qb-result{
  margin-top:18px;padding:14px;border-radius:10px;background:#f6f7f9;
  font-size:15px;text-align:center;color:#333;
}
.quiz-opt-row{
  display:flex;align-items:center;gap:10px;margin-bottom:10px;font-size:14px;color:#444;
}
.quiz-opt-row span:first-child{width:6em;flex:none;}
.quiz-opt-row input[type=number]{
  width:64px;border:1px solid #ddd;border-radius:8px;padding:8px 6px;font-size:14px;
  text-align:center;outline:none;
}
.quiz-opt-row input[type=number]:focus{border-color:var(--red);}

/* ============ Toast ============ */
.toast{
  position:fixed;left:50%;bottom:14%;transform:translateX(-50%) translateY(12px);
  background:rgba(0,0,0,.78);color:#fff;padding:10px 20px;border-radius:8px;
  font-size:14px;opacity:0;transition:.25s;pointer-events:none;z-index:300;
  max-width:80%;text-align:center;
}
.toast.show{opacity:1;transform:translateX(-50%) translateY(0);}