/* ===== 语桥 LinguaBridge 样式 ===== */
:root{
  --bg:#0f1226;
  --bg2:#161a38;
  --card:#1d2148;
  --card2:#23285a;
  --line:rgba(255,255,255,.08);
  --txt:#eef1ff;
  --txt2:#a9b0d8;
  --muted:#7a82ad;
  --pri:#6c8cff;
  --pri2:#8a6cff;
  --acc:#27d4b8;
  --warn:#ffb84d;
  --pink:#ff7eb3;
  --grad:linear-gradient(120deg,#6c8cff,#8a6cff 45%,#ff7eb3);
  --grad2:linear-gradient(120deg,#27d4b8,#6c8cff);
  --shadow:0 18px 50px rgba(0,0,0,.35);
  --r:16px;
  --r-sm:10px;
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",Roboto,sans-serif;
  background:var(--bg);color:var(--txt);line-height:1.6;min-height:100vh;
  overflow-x:hidden;
}
.container{max-width:1180px;margin:0 auto;padding:0 22px}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
.muted{color:var(--muted)}

/* ===== 顶部导航 ===== */
.topbar{position:sticky;top:0;z-index:50;background:rgba(15,18,38,.82);backdrop-filter:blur(14px);border-bottom:1px solid var(--line)}
.nav-inner{display:flex;align-items:center;justify-content:space-between;height:64px}
.brand{display:flex;align-items:baseline;gap:8px;font-weight:800}
.brand-logo{background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent;font-size:20px}
.brand-sub{color:var(--txt2);font-size:13px;letter-spacing:.5px}
.nav-links{display:flex;gap:6px}
.nav-links a{padding:8px 14px;border-radius:999px;color:var(--txt2);font-size:14px;font-weight:500;transition:.2s}
.nav-links a:hover,.nav-links a.active{color:#fff;background:rgba(255,255,255,.08)}
.nav-right{display:flex;align-items:center;gap:10px}
.user-chip{display:flex;align-items:center;gap:8px;padding:5px 10px 5px 6px;background:var(--card);border:1px solid var(--line);border-radius:999px}
.avatar{width:26px;height:26px;border-radius:50%;background:var(--grad);display:grid;place-items:center;font-size:13px;font-weight:700;color:#fff}
.uname{font-size:13px;color:var(--txt2)}
.btn{cursor:pointer;border:none;border-radius:999px;font-weight:600;font-size:14px;padding:10px 18px;transition:.2s}
.btn-ghost{background:rgba(255,255,255,.08);color:#fff}
.btn-ghost:hover{background:rgba(255,255,255,.16)}
.btn-pri{background:var(--grad);color:#fff}
.btn-pri:hover{filter:brightness(1.08);transform:translateY(-1px)}
.btn-outline{background:transparent;border:1px solid var(--line);color:var(--txt)}
.btn-outline:hover{border-color:var(--pri)}
.icon-btn{display:none;background:none;border:none;color:#fff;font-size:24px;cursor:pointer}

/* ===== 视图容器 ===== */
.view{min-height:calc(100vh - 64px - 240px);padding:32px 0 60px}
.section{padding:28px 0}
.sec-title{font-size:26px;font-weight:800;margin-bottom:6px}
.sec-desc{color:var(--txt2);margin-bottom:24px}

/* ===== 卡片网格 ===== */
.grid{display:grid;gap:18px}
.g3{grid-template-columns:repeat(3,1fr)}
.g2{grid-template-columns:repeat(2,1fr)}
.g4{grid-template-columns:repeat(4,1fr)}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:22px;transition:.22s}
.card:hover{transform:translateY(-4px);border-color:rgba(108,140,255,.4);box-shadow:var(--shadow)}

/* ===== 首页 Hero ===== */
.hero{position:relative;overflow:hidden;padding:64px 0 48px}
.hero::before{content:"";position:absolute;inset:-40% -10% auto -10%;height:520px;background:radial-gradient(circle at 20% 20%,rgba(108,140,255,.35),transparent 40%),radial-gradient(circle at 80% 0%,rgba(255,126,179,.25),transparent 45%);filter:blur(10px);z-index:-1}
.hero-tag{display:inline-flex;align-items:center;gap:8px;padding:6px 14px;border:1px solid var(--line);border-radius:999px;background:rgba(255,255,255,.04);font-size:13px;color:var(--txt2)}
.hero-tag .dot{width:7px;height:7px;border-radius:50%;background:var(--acc);box-shadow:0 0 10px var(--acc)}
.hero h1{font-size:clamp(34px,5vw,58px);font-weight:900;line-height:1.12;margin:18px 0 14px;letter-spacing:-.5px}
.hero h1 .grad{background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.hero p.lead{font-size:18px;color:var(--txt2);max-width:620px;margin-bottom:28px}
.hero-cta{display:flex;gap:14px;flex-wrap:wrap}
.hero-stats{display:flex;gap:34px;margin-top:42px;flex-wrap:wrap}
.hero-stats .stat .n{font-size:30px;font-weight:800;background:var(--grad2);-webkit-background-clip:text;background-clip:text;color:transparent}
.hero-stats .stat .l{font-size:13px;color:var(--muted)}

/* 语言选择卡 */
.lang-cards .lang-card{position:relative;overflow:hidden;cursor:pointer}
.lang-card .flag{font-size:42px;margin-bottom:10px}
.lang-card h3{font-size:20px;margin-bottom:4px}
.lang-card p{color:var(--txt2);font-size:13px;margin-bottom:14px}
.lang-card .level-bar{display:flex;gap:4px;margin-bottom:14px}
.lang-card .level-bar i{flex:1;height:5px;border-radius:3px;background:rgba(255,255,255,.1)}
.lang-card .level-bar i.on{background:var(--grad)}
.lang-card .go{color:var(--pri);font-size:13px;font-weight:600;display:inline-flex;align-items:center;gap:4px}

/* 功能区 */
.feat{display:flex;gap:14px;align-items:flex-start}
.feat .ic{flex:none;width:42px;height:42px;border-radius:12px;display:grid;place-items:center;font-size:20px;background:rgba(108,140,255,.16);color:var(--pri)}
.feat h4{font-size:16px;margin-bottom:2px}
.feat p{color:var(--txt2);font-size:13px}

/* ===== 分级课程 ===== */
.crumb{color:var(--muted);font-size:13px;margin-bottom:16px}
.crumb a{color:var(--pri)}
.lang-tabs{display:flex;gap:8px;margin-bottom:24px;flex-wrap:wrap}
.lang-tab{padding:8px 18px;border-radius:999px;border:1px solid var(--line);background:var(--card);cursor:pointer;font-weight:600;font-size:14px;color:var(--txt2);transition:.2s}
.lang-tab.active{background:var(--grad);color:#fff;border-color:transparent}
.level-card{cursor:pointer;position:relative;overflow:hidden}
.level-card .lv-badge{display:inline-block;font-size:12px;font-weight:700;padding:3px 10px;border-radius:999px;background:rgba(39,212,184,.16);color:var(--acc);margin-bottom:10px}
.level-card h3{font-size:18px;margin-bottom:6px}
.level-card p{color:var(--txt2);font-size:13px;margin-bottom:14px}
.level-card .meta{display:flex;justify-content:space-between;font-size:12px;color:var(--muted);margin-bottom:12px}
.progress{height:6px;border-radius:6px;background:rgba(255,255,255,.1);overflow:hidden}
.progress i{display:block;height:100%;background:var(--grad);border-radius:6px;transition:width .4s}
.lesson-list{margin-top:20px}
.lesson-item{display:flex;align-items:center;gap:14px;padding:14px 16px;background:var(--card2);border:1px solid var(--line);border-radius:var(--r-sm);margin-bottom:10px;transition:.2s;cursor:pointer}
.lesson-item:hover{border-color:var(--pri)}
.lesson-item .num{width:30px;height:30px;border-radius:50%;background:rgba(108,140,255,.2);color:var(--pri);display:grid;place-items:center;font-weight:700;font-size:13px;flex:none}
.lesson-item.done .num{background:var(--acc);color:#0f1226}
.lesson-item .info{flex:1}
.lesson-item .info h4{font-size:15px}
.lesson-item .info p{font-size:12px;color:var(--muted)}
.lesson-item .tag{font-size:11px;padding:2px 8px;border-radius:6px;background:rgba(255,255,255,.06);color:var(--txt2)}

/* ===== 互动学习模块 ===== */
.module-tabs{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin-bottom:28px}
.module-tab{padding:16px;border-radius:var(--r);background:var(--card);border:1px solid var(--line);cursor:pointer;text-align:center;transition:.2s}
.module-tab:hover{border-color:var(--pri);transform:translateY(-2px)}
.module-tab.active{background:var(--grad);border-color:transparent;color:#fff}
.module-tab .ic{font-size:26px;margin-bottom:6px}
.module-tab h4{font-size:14px}
.module-tab p{font-size:11px;color:var(--muted)}
.module-tab.active p{color:rgba(255,255,255,.85)}

.learn-stage{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:34px;min-height:420px}
.tts-bar{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin-bottom:18px;padding:12px 16px;background:var(--card);border:1px solid var(--line);border-radius:var(--r-sm)}
.stage-head{display:flex;justify-content:space-between;align-items:center;margin-bottom:24px}
.stage-head .left h3{font-size:20px}
.stage-head .left p{color:var(--muted);font-size:13px}
.stage-score{font-size:13px;color:var(--acc);font-weight:600}

/* 单词卡片 */
.flash{display:flex;flex-direction:column;align-items:center;padding:20px 0}
.flash-card{width:340px;max-width:100%;height:220px;perspective:1000px;cursor:pointer}
.flash-inner{position:relative;width:100%;height:100%;transition:transform .55s;transform-style:preserve-3d}
.flash.flipped .flash-inner{transform:rotateY(180deg)}
.flash-face{position:absolute;inset:0;border-radius:var(--r);display:flex;flex-direction:column;justify-content:center;align-items:center;padding:24px;backface-visibility:hidden;background:var(--card2);border:1px solid var(--line)}
.flash-face.back{transform:rotateY(180deg)}
.flash-word{font-size:32px;font-weight:800;margin-bottom:6px}
.flash-phonetic{color:var(--muted);font-size:14px;margin-bottom:10px}
.flash-meaning{color:var(--txt2);font-size:15px;text-align:center}
.flash-meaning-zh{font-size:20px;font-weight:700;color:var(--pri);margin-top:8px;text-align:center}
.flash-ex-cn{color:var(--muted);font-size:13px;text-align:center;margin-top:6px;font-style:italic}
.flash-hint{font-size:12px;color:var(--muted);margin-top:14px}
.speak-word-btn{margin-top:12px;padding:6px 16px;border-radius:999px;border:1px solid rgba(108,140,255,.5);background:rgba(108,140,255,.14);color:var(--pri);cursor:pointer;font-size:13px;font-weight:600;transition:.2s}
.speak-word-btn:hover{background:rgba(108,140,255,.28)}
.flash-ctrl{display:flex;gap:12px;margin-top:24px}
.chip-btn{padding:10px 22px;border-radius:999px;border:1px solid var(--line);background:var(--card2);color:var(--txt);cursor:pointer;font-weight:600;font-size:14px;transition:.2s}
.chip-btn:hover{border-color:var(--pri)}
.chip-btn.good{border-color:var(--acc);color:var(--acc)}
.chip-btn.bad{border-color:#ff6b8a;color:#ff6b8a}

/* 语法选择 */
.q-box .q-text{font-size:17px;margin-bottom:18px;font-weight:600}
.opts{display:grid;gap:10px}
.opt{padding:14px 16px;border:1px solid var(--line);border-radius:var(--r-sm);background:var(--card2);cursor:pointer;transition:.2s;display:flex;align-items:center;gap:10px}
.opt:hover{border-color:var(--pri)}
.opt .key{width:26px;height:26px;border-radius:50%;background:rgba(255,255,255,.08);display:grid;place-items:center;font-size:13px;font-weight:700;flex:none}
.opt.correct{border-color:var(--acc);background:rgba(39,212,184,.12)}
.opt.wrong{border-color:#ff6b8a;background:rgba(255,107,138,.1)}
.q-feedback{margin-top:14px;padding:14px;border-radius:var(--r-sm);font-size:14px;display:none}
.q-feedback.show{display:block}
.q-feedback.ok{background:rgba(39,212,184,.12);color:var(--acc)}
.q-feedback.no{background:rgba(255,107,138,.1);color:#ff8fa3}

/* 口语跟读 */
.speak-box{text-align:center}
.speak-target{font-size:30px;font-weight:800;margin:10px 0 6px}
.speak-roman{color:var(--muted);font-size:14px;margin-bottom:6px}
.speak-trans{color:var(--txt2);font-size:15px;margin-bottom:22px}
.speak-mic{width:84px;height:84px;border-radius:50%;border:none;background:var(--grad);color:#fff;font-size:32px;cursor:pointer;display:grid;place-items:center;margin:0 auto 16px;transition:.2s;box-shadow:0 10px 30px rgba(108,140,255,.4)}
.speak-mic:hover{transform:scale(1.06)}
.speak-mic.rec{background:linear-gradient(120deg,#ff6b8a,#ff7eb3);animation:pulse 1.3s infinite}
@keyframes pulse{0%,100%{box-shadow:0 0 0 0 rgba(255,107,138,.5)}50%{box-shadow:0 0 0 18px rgba(255,107,138,0)}}
.speak-result{margin-top:18px;font-size:14px}
.speak-result .score{font-size:30px;font-weight:800;background:var(--grad2);-webkit-background-clip:text;background-clip:text;color:transparent}

/* 听力训练 */
.listen-box{text-align:center}
.listen-audio{display:none}
.listen-play{padding:14px 26px;border-radius:999px;border:none;background:var(--grad2);color:#fff;font-weight:600;cursor:pointer;font-size:15px;margin-bottom:20px}
.listen-q{font-size:16px;color:var(--txt2);margin-bottom:18px}

/* 完成态 */
.done-box{text-align:center;padding:40px 0}
.done-box .em{font-size:54px;margin-bottom:12px}
.done-box h3{font-size:22px;margin-bottom:6px}
.done-box p{color:var(--txt2);margin-bottom:20px}

/* ===== 学习进度 ===== */
.stat-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;margin-bottom:28px}
.stat-card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:20px}
.stat-card .ic{font-size:22px;margin-bottom:8px}
.stat-card .n{font-size:28px;font-weight:800}
.stat-card .l{font-size:13px;color:var(--muted)}
.ring-wrap{display:flex;align-items:center;gap:24px;flex-wrap:wrap}
.ring{width:150px;height:150px}
.ring-legend .li{display:flex;align-items:center;gap:8px;margin-bottom:8px;font-size:14px}
.ring-legend .li i{width:12px;height:12px;border-radius:3px}
.heatmap{display:grid;grid-template-columns:repeat(14,1fr);gap:5px;margin-top:8px}
.heatmap i{aspect-ratio:1;border-radius:4px;background:rgba(255,255,255,.06)}
.heatmap i[data-l="1"]{background:rgba(108,140,255,.3)}
.heatmap i[data-l="2"]{background:rgba(108,140,255,.55)}
.heatmap i[data-l="3"]{background:rgba(108,140,255,.8)}
.heatmap i[data-l="4"]{background:var(--pri)}

/* ===== 成就 ===== */
.achv-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.achv{display:flex;gap:14px;align-items:center;padding:18px;background:var(--card);border:1px solid var(--line);border-radius:var(--r);transition:.2s}
.achv.locked{opacity:.45;filter:grayscale(.6)}
.achv .medal{flex:none;width:52px;height:52px;border-radius:50%;display:grid;place-items:center;font-size:24px;background:var(--grad);color:#fff}
.achv.locked .medal{background:rgba(255,255,255,.1)}
.achv h4{font-size:15px}
.achv p{font-size:12px;color:var(--muted)}

/* ===== 学习路径推荐 ===== */
.path-wrap{position:relative}
.path-node{display:flex;gap:16px;margin-bottom:6px}
.path-node .dot{flex:none;width:38px;height:38px;border-radius:50%;background:var(--card2);border:2px solid var(--line);display:grid;place-items:center;font-weight:700;color:var(--pri);position:relative;z-index:2}
.path-node.done .dot{background:var(--acc);border-color:var(--acc);color:#0f1226}
.path-node.cur .dot{border-color:var(--pri);box-shadow:0 0 0 5px rgba(108,140,255,.2)}
.path-node .line{flex:none;width:2px;background:var(--line);margin:0 18px}
.path-node:not(:last-child) .line{min-height:46px}
.path-node .content{flex:1;padding-bottom:18px}
.path-node .content h4{font-size:15px;margin-bottom:2px}
.path-node .content p{font-size:13px;color:var(--muted)}
.path-node .content .acts{margin-top:8px;display:flex;gap:8px;flex-wrap:wrap}

/* ===== 社区 ===== */
.post-input{display:flex;gap:12px;margin-bottom:24px}
.post-input textarea{flex:1;background:var(--card);border:1px solid var(--line);border-radius:var(--r-sm);color:var(--txt);padding:14px;resize:none;font-family:inherit;font-size:14px;min-height:70px}
.post-input textarea:focus{outline:none;border-color:var(--pri)}
.post{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:18px;margin-bottom:14px}
.post-head{display:flex;align-items:center;gap:10px;margin-bottom:10px}
.post-head .avatar{width:36px;height:36px;font-size:14px}
.post-head .meta .name{font-weight:600;font-size:14px}
.post-head .meta .time{font-size:12px;color:var(--muted)}
.post-body{font-size:14px;margin-bottom:12px;color:var(--txt)}
.post-tag{display:inline-block;font-size:11px;padding:2px 8px;border-radius:6px;background:rgba(108,140,255,.15);color:var(--pri);margin-right:6px}
.post-foot{display:flex;gap:18px;font-size:13px;color:var(--muted)}
.post-foot button{background:none;border:none;color:var(--muted);cursor:pointer;display:flex;align-items:center;gap:5px;font-size:13px}
.post-foot button:hover{color:var(--pri)}

/* ===== 登录注册 ===== */
.auth-wrap{max-width:420px;margin:30px auto}
.auth-card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:32px}
.auth-tabs{display:flex;gap:8px;margin-bottom:24px;background:var(--card2);padding:5px;border-radius:999px}
.auth-tabs button{flex:1;padding:9px;border:none;background:none;color:var(--txt2);border-radius:999px;cursor:pointer;font-weight:600;font-size:14px;transition:.2s}
.auth-tabs button.active{background:var(--grad);color:#fff}
.field{margin-bottom:16px}
.field label{display:block;font-size:13px;color:var(--txt2);margin-bottom:6px}
.field input{width:100%;padding:12px 14px;background:var(--card2);border:1px solid var(--line);border-radius:var(--r-sm);color:var(--txt);font-size:14px;font-family:inherit}
.field input:focus{outline:none;border-color:var(--pri)}

/* ===== Toast ===== */
.toast{position:fixed;bottom:28px;left:50%;transform:translateX(-50%) translateY(80px);background:var(--card2);border:1px solid var(--line);color:#fff;padding:12px 22px;border-radius:999px;font-size:14px;z-index:200;opacity:0;transition:.3s;box-shadow:var(--shadow)}
.toast.show{opacity:1;transform:translateX(-50%) translateY(0)}

/* ===== Footer ===== */
.footer{background:var(--bg2);border-top:1px solid var(--line);padding:40px 0 20px}
.footer-inner{display:flex;justify-content:space-between;gap:30px;flex-wrap:wrap;padding-bottom:24px;border-bottom:1px solid var(--line)}
.footer-cols{display:flex;gap:50px;flex-wrap:wrap}
.footer-cols h4{font-size:13px;color:var(--muted);margin-bottom:10px;font-weight:600}
.footer-cols a{display:block;font-size:13px;color:var(--txt2);margin-bottom:6px}
.footer-cols a:hover{color:var(--pri)}
.footer-bottom{padding-top:18px;font-size:12px;color:var(--muted);text-align:center}

/* ===== 响应式 ===== */
@media(max-width:880px){
  .nav-links{display:none}
  .icon-btn{display:block}
  .nav-links.open{display:flex;flex-direction:column;position:absolute;top:64px;left:0;right:0;background:var(--bg2);padding:14px 22px;border-bottom:1px solid var(--line)}
  .g3,.g4,.stat-grid,.module-tabs,.achv-grid{grid-template-columns:repeat(2,1fr)}
  .g2{grid-template-columns:1fr}
  .hero h1{font-size:32px}
}
@media(max-width:520px){
  .g3,.g4,.stat-grid,.module-tabs,.achv-grid{grid-template-columns:1fr}
  .user-chip .uname{display:none}
}