/* ============ 全龄英语学习平台 · 全局样式 ============ */
:root{
  --blue:#2563eb; --blue-d:#1d4ed8; --blue-l:#60a5fa;
  --ink:#1a2a3a; --sub:#5a6b7d; --line:#dbe3ec; --bg:#f4f7fb; --card:#ffffff;
  --green:#2fa36b; --amber:#e89b2c; --rose:#d8587b; --violet:#7a5fc0;
  --radius:12px; --shadow:0 6px 20px rgba(15,43,70,.08);
}
*{box-sizing:border-box;margin:0;padding:0}
html,body{font-family:-apple-system,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;color:var(--ink);background:var(--bg);line-height:1.6;-webkit-text-size-adjust:100%}
a{color:var(--blue);text-decoration:none}
img{max-width:100%;display:block}
ul{list-style:none}

/* 全站容器：桌面 1600px，小屏自适应 */
.container{width:100%;max-width:1600px;margin:0 auto;padding:0 24px}
@media(max-width:768px){.container{padding:0 14px}}

/* ============ 顶部 200px 蓝调渐变页头 ============ */
.site-header{
  height:200px;
  background:linear-gradient(135deg,#0f2b46 0%,#1d4ed8 45%,#3b82f6 75%,#7ab7ff 100%);
  background-size:cover;background-position:center;
  color:#fff;position:relative;overflow:hidden;
}
.site-header::before{content:"";position:absolute;inset:0;background:radial-gradient(circle at 85% 20%,rgba(255,255,255,.25),transparent 45%)}
.header-inner{position:relative;z-index:2;height:200px;display:flex;flex-direction:column;justify-content:center}
.site-title{font-size:34px;font-weight:800;letter-spacing:.5px;line-height:1.2}
.site-title .en{font-size:17px;font-weight:600;opacity:.9;letter-spacing:2px;display:block;margin-top:4px}
.site-slogan{margin-top:8px;font-size:16px;opacity:.92}
.header-top{position:relative;z-index:2;display:flex;justify-content:space-between;align-items:center;padding:16px 0 0}
.brand{font-size:22px;font-weight:800;display:flex;align-items:center;gap:10px}
.brand .logo{width:38px;height:38px;background:#fff;color:var(--blue-d);border-radius:9px;display:flex;align-items:center;justify-content:center;font-size:20px;font-weight:900}
.user-actions{display:flex;gap:10px;align-items:center}
@media(max-width:768px){.site-header,.header-inner{height:auto;min-height:150px;padding-bottom:14px}.site-title{font-size:24px}}

/* ============ 主导航 ============ */
.main-nav{background:#fff;border-bottom:1px solid var(--line);position:sticky;top:0;z-index:50;box-shadow:0 2px 8px rgba(15,43,70,.05)}
.nav-inner{display:flex;align-items:center;gap:4px;flex-wrap:wrap;padding:0 24px;max-width:1600px;margin:0 auto}
.nav-inner a{padding:12px 14px;font-size:15px;font-weight:600;color:var(--sub);border-bottom:3px solid transparent;transition:.2s}
.nav-inner a:hover,.nav-inner a.active{color:var(--blue);border-bottom-color:var(--blue)}
@media(max-width:768px){.nav-inner a{padding:10px 9px;font-size:13px}}

/* ============ 通用组件 ============ */
.section{padding:44px 0}
.section-tight{padding:28px 0}
.section-head{margin-bottom:22px}
.section-head h2{font-size:26px;font-weight:800;color:var(--ink)}
.section-head p{color:var(--sub);margin-top:6px;max-width:760px}
.section-head .tag{display:inline-block;background:#eaf2fb;color:var(--blue-d);font-size:13px;font-weight:700;padding:3px 10px;border-radius:20px;margin-bottom:8px}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:20px}
.grid{display:grid;gap:16px}
.g4{grid-template-columns:repeat(4,1fr)}
.g3{grid-template-columns:repeat(3,1fr)}
.g2{grid-template-columns:repeat(2,1fr)}
@media(max-width:1024px){.g4{grid-template-columns:repeat(2,1fr)}}
@media(max-width:768px){.g4,.g3,.g2{grid-template-columns:1fr}}

.btn{display:inline-block;padding:11px 22px;border-radius:8px;font-size:15px;font-weight:700;border:none;cursor:pointer;transition:.2s;text-align:center}
.btn-primary{background:var(--blue);color:#fff}
.btn-primary:hover{background:var(--blue-d)}
.btn-light{background:#fff;color:var(--blue-d);border:1px solid var(--line)}
.btn-ghost{background:transparent;color:#fff;border:1px solid rgba(255,255,255,.7)}
.btn-green{background:var(--green);color:#fff}
.btn-sm{padding:7px 14px;font-size:13px}
.tag-pill{display:inline-block;padding:2px 9px;border-radius:20px;font-size:12px;font-weight:700}
.badge{background:#eaf2fb;color:var(--blue-d)}

/* 阶段色条 */
.st-age{background:#eaf2fb;border-left:5px solid var(--blue)}
.st-primary{background:#e6f2ec;border-left:5px solid var(--green)}
.st-junior{background:#eef3e4;border-left:5px solid #a3b83c}
.st-senior{background:#fdf1e0;border-left:5px solid var(--amber)}
.st-college{background:#fbeaea;border-left:5px solid var(--rose)}
.st-adult{background:#efe9fb;border-left:5px solid var(--violet)}

/* 步骤条 */
.steps{display:flex;gap:0;align-items:center;flex-wrap:wrap}
.step{flex:1;min-width:130px;text-align:center;position:relative}
.step .n{width:34px;height:34px;border-radius:50%;background:var(--blue);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:800;margin:0 auto 8px}
.step .t{font-size:13px;font-weight:600}
.step:not(:last-child)::after{content:"";position:absolute;top:17px;left:calc(50% + 20px);width:calc(100% - 40px);height:2px;background:var(--line)}

/* 表格 */
table{width:100%;border-collapse:collapse;font-size:14px}
th,td{padding:10px 12px;border-bottom:1px solid var(--line);text-align:left}
th{background:#eef3fb;font-weight:700}
tr:hover td{background:#f8fafe}

/* 页脚六栏 */
.site-footer{background:#0f2b46;color:#c7d4e2;margin-top:40px}
.footer-inner{max-width:1600px;margin:0 auto;padding:44px 24px 24px;display:grid;grid-template-columns:1.4fr repeat(4,1fr) 1.2fr;gap:26px}
.footer-col h4{color:#fff;font-size:15px;margin-bottom:12px}
.footer-col a,.footer-col li{font-size:13px;color:#b9c8d8;line-height:2}
.footer-col a:hover{color:#fff}
.footer-brand{font-size:20px;font-weight:800;color:#fff;margin-bottom:10px}
.footer-brand .en{font-size:12px;opacity:.7;letter-spacing:1px;display:block;margin-top:4px}
.footer-contact li{line-height:2}
.footer-bottom{border-top:1px solid rgba(255,255,255,.12);max-width:1600px;margin:0 auto;padding:16px 24px;font-size:12px;color:#8fa3b8;text-align:center}
@media(max-width:1024px){.footer-inner{grid-template-columns:repeat(3,1fr)}}
@media(max-width:768px){.footer-inner{grid-template-columns:repeat(2,1fr)}}

/* 首页 hero 之下内容卡片 hover */
.card-link{cursor:pointer;transition:.2s}
.card-link:hover{transform:translateY(-4px);box-shadow:0 12px 28px rgba(15,43,70,.14)}

/* 移动端导航切换按钮 */
.nav-toggle{display:none}
@media(max-width:768px){
  .nav-toggle{display:inline-flex;align-items:center;gap:6px;font-size:13px;color:#fff;background:rgba(255,255,255,.18);padding:7px 12px;border-radius:8px;border:none;cursor:pointer;font-weight:600}
  .nav-inner{flex-wrap:nowrap;overflow-x:auto;-webkit-overflow-scrolling:touch}
}

/* 标签页 */
.tabs{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:18px}
.tab{padding:8px 16px;border-radius:20px;background:#fff;border:1px solid var(--line);font-size:14px;font-weight:600;color:var(--sub);cursor:pointer}
.tab.active{background:var(--blue);color:#fff;border-color:var(--blue)}

/* 进度条 */
.progress{height:10px;background:#e7edf5;border-radius:20px;overflow:hidden}
.progress>span{display:block;height:100%;background:linear-gradient(90deg,var(--blue),var(--blue-l));border-radius:20px}

/* 词卡翻转 */
.flip-card{perspective:1000px;cursor:pointer}
.flip-inner{position:relative;width:100%;min-height:220px;transition:transform .5s;transform-style:preserve-3d}
.flip-card.flipped .flip-inner{transform:rotateY(180deg)}
.flip-face{position:absolute;inset:0;backface-visibility:hidden;display:flex;flex-direction:column;align-items:center;justify-content:center;border-radius:var(--radius);padding:24px;text-align:center}
.flip-front{background:#fff;border:1px solid var(--line)}
.flip-back{background:var(--blue);color:#fff;transform:rotateY(180deg)}
.flip-word{font-size:34px;font-weight:800}
.flip-pos{font-size:13px;color:var(--sub);margin-top:4px}
.flip-meaning{font-size:18px;font-weight:600;margin-top:10px}

/* 测验选项 */
.q-opt{display:block;width:100%;text-align:left;padding:12px 16px;border:1px solid var(--line);border-radius:8px;background:#fff;margin-bottom:10px;font-size:15px;cursor:pointer;transition:.15s}
.q-opt:hover{border-color:var(--blue)}
.q-opt.correct{border-color:var(--green);background:#e6f2ec;font-weight:700}
.q-opt.wrong{border-color:var(--rose);background:#fbeaea}

/* AI 口语对话气泡 */
.chat-box{background:#fff;border:1px solid var(--line);border-radius:12px;padding:16px;max-height:380px;overflow-y:auto;display:flex;flex-direction:column;gap:10px}
.bubble{max-width:78%;padding:10px 14px;border-radius:14px;font-size:14px;line-height:1.5}
.bubble.ai{background:#eaf2fb;align-self:flex-start;border-bottom-left-radius:4px}
.bubble.me{background:var(--blue);color:#fff;align-self:flex-end;border-bottom-right-radius:4px}

/* 每日打卡圈 */
.streak-ring{width:120px;height:120px;margin:0 auto;position:relative}
.streak-ring svg{transform:rotate(-90deg)}
.streak-num{position:absolute;inset:0;display:flex;flex-direction:column;align-items:center;justify-content:center}

/* 实用工具类 */
.mt-8{margin-top:8px}.mt-16{margin-top:16px}.mb-8{margin-bottom:8px}.mb-16{margin-bottom:16px}
.center{text-align:center}.muted{color:var(--sub)}.bold{font-weight:700}
.flex{display:flex;gap:10px;align-items:center}.wrap{flex-wrap:wrap}
.hidden{display:none!important}

/* ============ 页头全站搜索框（深色渐变页头内，两主题通用） ============ */
.site-search{display:flex;align-items:center;gap:6px;background:rgba(255,255,255,.16);border:1px solid rgba(255,255,255,.35);border-radius:20px;padding:2px 4px 2px 12px}
.site-search input{background:transparent;border:none;outline:none;color:#fff;font-size:13px;width:130px}
.site-search input::placeholder{color:rgba(255,255,255,.75)}
.site-search button{background:transparent;border:none;cursor:pointer;font-size:14px;padding:3px 8px;border-radius:50%}
@media(max-width:768px){.site-search input{width:80px}}

/* ============ 深色模式（:root 浅色默认值保持不变，仅覆盖） ============ */
:root[data-theme="dark"]{
  --blue:#60a5fa; --blue-d:#3b82f6; --blue-l:#93c5fd;
  --ink:#c7d4e2; --sub:#8fa3b8; --line:#2a3a4d; --bg:#0f1b2a; --card:#121f31;
  --green:#34d399; --amber:#fbbf24; --rose:#fb7185; --violet:#a78bfa;
  --shadow:0 6px 20px rgba(0,0,0,.35);
}
/* 页头渐变在深色下加深 */
:root[data-theme="dark"] .site-header{background:linear-gradient(135deg,#071220 0%,#123055 45%,#1d4ed8 80%,#3b82f6 100%)}
/* CSS 类中硬编码浅色值的深色适配 */
:root[data-theme="dark"] .main-nav{background:#121f31;border-bottom-color:var(--line)}
:root[data-theme="dark"] .tab{background:#121f31;border-color:var(--line)}
:root[data-theme="dark"] .q-opt{background:#121f31}
:root[data-theme="dark"] .chat-box{background:#121f31}
:root[data-theme="dark"] .flip-front{background:#121f31}
:root[data-theme="dark"] .btn-light{background:#121f31;color:var(--blue-l)}
:root[data-theme="dark"] .tag,:root[data-theme="dark"] .badge{background:#16233a;color:var(--blue-l)}
:root[data-theme="dark"] .st-age{background:#16233a}
:root[data-theme="dark"] .st-primary{background:#122a20}
:root[data-theme="dark"] .st-junior{background:#1a2410}
:root[data-theme="dark"] .st-senior{background:#242010}
:root[data-theme="dark"] .st-college{background:#2a1620}
:root[data-theme="dark"] .st-adult{background:#1e1a30}
:root[data-theme="dark"] th{background:#16233a}
:root[data-theme="dark"] tr:hover td{background:#0d1a29}
:root[data-theme="dark"] .progress{background:#1c2b3f}
:root[data-theme="dark"] .bubble.ai{background:#16233a}
:root[data-theme="dark"] .q-opt.correct{background:#122a20}
:root[data-theme="dark"] .q-opt.wrong{background:#2a1620}
:root[data-theme="dark"] .card-link:hover{box-shadow:0 12px 28px rgba(0,0,0,.5)}
/* 页面内联硬编码浅色值覆盖（属性选择器，!important）——通用白底放前，暖调深色放后 */
:root[data-theme="dark"] [style*="background:#fff;"],
:root[data-theme="dark"] [style$="background:#fff"]{background:#121f31!important}
:root[data-theme="dark"] [style*="#f8fafe"]{background:#0d1a29!important}
:root[data-theme="dark"] [style*="#eaf2fb"]{background:#16233a!important}
:root[data-theme="dark"] [style*="#eef3fb"]{background:#16233a!important}
:root[data-theme="dark"] [style*="#f4f7fb"]{background:#0f1b2a!important}
:root[data-theme="dark"] [style*="#f8fafc"]{background:#121f31!important}
:root[data-theme="dark"] [style*="#eef4ff"]{background:#16233a!important}
:root[data-theme="dark"] [style*="#fdf1e0"]{background:#242010!important}
:root[data-theme="dark"] [style*="#fbeaea"]{background:#2a1620!important}
:root[data-theme="dark"] [style*="#e6f2ec"]{background:#122a20!important}
:root[data-theme="dark"] [style*="#eef3e4"]{background:#1a2410!important}
:root[data-theme="dark"] [style*="#efe9fb"]{background:#1e1a30!important}
:root[data-theme="dark"] [style*="#fffbeb"]{background:#242010!important}
:root[data-theme="dark"] [style*="#fef3c7"]{background:#2a2410!important}
:root[data-theme="dark"] [style*="#dbeafe"]{background:#16233a!important}
/* 内联硬编码文字色 / 边框色 */
:root[data-theme="dark"] [style*="color:#3a4d60"]{color:#c7d4e2!important}
:root[data-theme="dark"] [style*="color:#5a6b7d"]{color:#8fa3b8!important}
:root[data-theme="dark"] [style*="color:#334155"]{color:#c7d4e2!important}
:root[data-theme="dark"] [style*="color:#94a3b8"]{color:#8fa3b8!important}
:root[data-theme="dark"] [style*="color:#b45309"]{color:#fbbf24!important}
:root[data-theme="dark"] [style*="#dbe3ec"],
:root[data-theme="dark"] [style*="#e2e8f0"]{border-color:#2a3a4d!important}
:root[data-theme="dark"] [style*="#fde68a"]{border-color:#6b5a2a!important}

/* ============ 登录/注册模态框（复用全局 CSS 变量，深色模式自动适配） ============ */
.auth-modal{position:fixed;inset:0;z-index:1000;background:rgba(10,20,35,.55);display:flex;align-items:center;justify-content:center;padding:20px}
.auth-card{position:relative;width:100%;max-width:380px;padding:28px 26px !important;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);box-shadow:0 18px 50px rgba(0,0,0,.28)}
.auth-close{position:absolute;top:12px;right:14px;background:none;border:none;font-size:18px;line-height:1;cursor:pointer;color:var(--sub)}
.auth-close:hover{color:var(--ink)}
.auth-tabs{display:flex;gap:8px;margin-bottom:18px}
.auth-tab{flex:1;padding:9px 0;text-align:center;border-radius:8px;background:transparent;border:1px solid var(--line);color:var(--sub);font-size:14px;font-weight:700;cursor:pointer;transition:.15s}
.auth-tab.active{background:var(--blue);color:#fff;border-color:var(--blue)}
.auth-input{width:100%;padding:11px 13px;margin-bottom:12px;border:1px solid var(--line);border-radius:8px;background:transparent;color:var(--ink);font-size:14px;outline:none;box-sizing:border-box}
.auth-input:focus{border-color:var(--blue);box-shadow:0 0 0 3px rgba(37,99,235,.14)}
.auth-err{color:var(--rose);font-size:13px;min-height:18px;margin:2px 0 10px}