:root {
    --brand-blue: #007AFF;
    --brand-blue-hover: #1A87FF;
    --brand-blue-shadow: #0047FF;
    --duo-green: #58CC02;
    --duo-orange: #FF9600;
    --duo-red: #FF4B4B;
    --duo-purple: #A652FF;
    --bg-white: #FFFFFF;
    --text-black: #3C3C3C;
    --radius: 24px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
body { 
    font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "PingFang SC", "Helvetica Neue", sans-serif; 
    background: var(--bg-white); 
    color: var(--text-black);
    overflow-x: hidden;
}

p { margin-bottom: 12px; }

/* 导航 */
.navbar { 
    padding: 20px 50px; 
    display: flex; 
    justify-content: space-between; 
    align-items: center; 
    border-bottom: 2px solid #F0F0F0; 
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(10px);
    position: sticky;
    top: 0;
    z-index: 100;
}
.nav-brand { display: flex; align-items: center; gap: 12px; }
.nav-brand h2 { font-size: 20px; font-weight: 800; letter-spacing: -0.5px; }
.nav-logo { height: 36px; width: 36px; border-radius: 8px; object-fit: cover; }
.nav-links { display: flex; align-items: center; }
.nav-btn-main { 
    text-decoration: none; 
    font-weight: 800; 
    color: var(--brand-blue); 
    font-size: 15px; 
    padding: 8px 16px;
    border-radius: 12px;
    transition: 0.2s;
}
.nav-btn-main:hover { background: #F0F7FF; }

/* Hero 区 */
.hero { padding: 80px 50px 100px; display: flex; justify-content: center; background: radial-gradient(circle at top right, #F0F7FF 0%, #FFF 60%); }
.hero-main { max-width: 1200px; width: 100%; display: flex; align-items: center; gap: 60px; }
.hero-text { flex: 1.2; }
.hero-text h1 { font-size: 56px; line-height: 1.15; letter-spacing: -1.5px; margin-bottom: 24px; font-weight: 900; }
.blue-text { color: var(--brand-blue); }

/* 词库标签“线路图” - 流式响应式布局 */
.vocab-network { 
    margin-bottom: 40px; 
    display: flex; 
    flex-wrap: wrap; 
    gap: 10px; 
    align-items: center;
}
.v-tag { 
    padding: 8px 16px; 
    border-radius: 100px; 
    font-weight: 800; 
    font-size: 13px; 
    border: 2px solid #E5E5E5; 
    background: #FFF;
    transition: all 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275); 
    cursor: default;
    user-select: none;
}
.v-tag:hover { transform: translateY(-3px) scale(1.03); border-color: var(--brand-blue); box-shadow: 0 5px 15px rgba(0,122,255,0.1); }
.t-blue { color: var(--brand-blue); }
.t-green { color: var(--duo-green); }
.t-yellow { color: var(--duo-orange); }
.t-orange { color: var(--duo-orange); }
.t-red { color: var(--duo-red); }
.t-purple { color: var(--duo-purple); }
.v-line-connect { font-size: 13px; color: #999; font-weight: 800; letter-spacing: 1px; padding-left: 5px; }

/* 按钮：Duolingo 质感升级 */
.btn-express {
    display: inline-block; 
    padding: 20px 40px; 
    background: var(--brand-blue); 
    color: #FFF; 
    text-decoration: none; 
    border-radius: 18px; 
    font-weight: 800; 
    font-size: 18px;
    box-shadow: 0 6px 0 var(--brand-blue-shadow); 
    transition: transform 0.1s ease, box-shadow 0.1s ease, background-color 0.2s;
}
.btn-express:hover { background-color: var(--brand-blue-hover); transform: translateY(-2px); box-shadow: 0 8px 0 var(--brand-blue-shadow); }
.btn-express:active { transform: translateY(4px); box-shadow: 0 2px 0 var(--brand-blue-shadow); }

/* 【重点修复】手机模型自适应（解决压扁与跳脱问题） */
.hero-mockup { 
    flex: 0.8; 
    display: flex; 
    justify-content: center; 
    align-items: center;
}
.phone-case { 
    width: 100%;
    max-width: 290px; /* 控制桌面端标准大小 */
    background: #000;
    border: 11px solid #121212; 
    border-radius: 42px; 
    box-shadow: 0 40px 80px rgba(0,0,0,0.15);
    overflow: hidden;
    line-height: 0;   /* 移除图片底部的幽灵白边 */
}
.full-shot { 
    width: 100%; 
    height: auto;      /* 依靠图片本身高度撑开，决不强行扭曲比例 */
    display: block;
    object-fit: contain; 
}

/* 黑色滚动条（通用） */
.rolling-bar, .town-rolling-bar { background: #1a1a1a; padding: 15px 0; overflow: hidden; }
.rolling-inner, .town-rolling-inner { display: flex; width: max-content; animation: move 30s linear infinite; }
.rolling-inner span, .town-rolling-inner span { color: #fff; font-size: 14px; font-weight: 900; letter-spacing: 2px; padding: 0 40px; }

@keyframes move { 
    from { transform: translateX(0); } 
    to { transform: translateX(-50%); } 
}

/* 核心玩法四重奏 */
.gameplay-flow { padding: 100px 50px; max-width: 1300px; margin: 0 auto; }
.section-title { font-size: 38px; font-weight: 900; text-align: center; margin-bottom: 60px; letter-spacing: -0.5px; }
.shot-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 30px; }
.shot-card { transition: 0.4s cubic-bezier(0.2, 0.8, 0.2, 1); }
.shot-card:hover { transform: translateY(-10px); }
.shot-frame { 
    width: 100%; 
    aspect-ratio: 9/16; 
    background: #F8F8F8; 
    border-radius: 20px; 
    overflow: hidden; 
    border: 1px solid #EEE;
    margin-bottom: 20px; 
    box-shadow: 0 10px 30px rgba(0,0,0,0.04);
}
.shot-frame img { width: 100%; height: 100%; object-fit: cover; }
.badge { 
    display: inline-block; padding: 4px 10px; background: #E5F2FF; 
    color: var(--brand-blue); border-radius: 8px; font-weight: 800; font-size: 11px; margin-bottom: 12px;
}
.shot-desc h3 { font-size: 20px; font-weight: 800; margin-bottom: 8px; }
.shot-desc p { font-size: 14px; color: #667085; line-height: 1.6; }


/* 【新增板块】中间蓝色、反向滚动的微倾斜过渡条 */
.mid-rolling-bar { 
    background: var(--brand-blue); 
    padding: 14px 0; 
    overflow: hidden; 
    transform: rotate(-1deg); /* 潮牌杂志感微倾斜 */
    margin: 50px 0;
    box-shadow: 0 8px 24px rgba(0, 122, 255, 0.15);
}
.mid-rolling-inner { 
    display: flex; 
    width: max-content; 
    animation: move-reverse 28s linear infinite; /* 与黑色错开，形成对冲视觉特效 */
}
.mid-rolling-inner span { 
    color: #fff; 
    font-size: 14px; 
    font-weight: 900; 
    letter-spacing: 2px; 
    padding: 0 45px; 
    text-transform: uppercase;
}

@keyframes move-reverse { 
    from { transform: translateX(-50%); } 
    to { transform: translateX(0); } 
}


/* 车站小镇特色区 */
.town-feature {
    max-width: 1300px;
    margin: 0 auto;
    padding: 60px 50px 80px;
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 60px;
    align-items: center;
}
.town-copy h2 { font-size: 40px; font-weight: 900; line-height: 1.2; margin: 14px 0 20px; letter-spacing: -0.5px; }
.town-copy p { font-size: 16px; line-height: 1.7; color: #5F6B7A; }
.town-lead { font-weight: 700; color: #3C3C3C; margin-bottom: 16px; }
.town-detail-list { display: grid; gap: 20px; margin-top: 26px; }
.town-detail-list h3 { font-size: 18px; font-weight: 800; margin-bottom: 6px; color: #1a1a1a; }
.town-detail-list p { font-size: 14px; line-height: 1.6; margin-bottom: 0; }

.town-showcase { display: grid; grid-template-columns: 180px 1fr; gap: 20px; align-items: center; }
.town-phone { border: 8px solid #121212; border-radius: 30px; overflow: hidden; background: #000; box-shadow: 0 25px 50px rgba(0,0,0,0.12); }
.town-phone img { width: 100%; display: block; }
.town-panorama { display: grid; gap: 16px; }
.town-panorama img { width: 100%; display: block; border-radius: 16px; border: 1px solid #E8EEF5; box-shadow: 0 15px 35px rgba(0,0,0,0.06); }


/* 底部区域 */
.site-footer { margin-top: 80px; padding: 60px 40px 40px; background: #F7F9FC; border-top: 1px solid #EEF1F5; border-radius: 40px 40px 0 0; }
.footer-inner { max-width: 1200px; margin: 0 auto; display: flex; flex-direction: column; gap: 30px; }
.footer-brand { display: flex; align-items: center; gap: 14px; }
.footer-brand img { width: 44px; height: 44px; border-radius: 10px; }
.footer-brand h3 { font-size: 18px; font-weight: 800; margin-bottom: 2px; }
.footer-brand p { font-size: 13px; color: #8A8A8A; }
.footer-links { display: flex; gap: 24px; flex-wrap: wrap; }
.footer-links a { text-decoration: none; color: #5F6B7A; font-weight: 700; font-size: 14px; transition: 0.2s; }
.footer-links a:hover { color: var(--brand-blue); }
.footer-bottom { padding-top: 20px; border-top: 1px solid #EAECEF; font-size: 13px; color: #98A2B3; }

/* 微信遮罩层 */
.wx-mask { display: none; position: fixed; z-index: 9999; inset: 0; background: rgba(12, 16, 24, 0.68); backdrop-filter: blur(2px); justify-content: flex-end; align-items: stretch; padding: 18px 16px max(22px, env(safe-area-inset-bottom)); flex-direction: column; }
.wx-card { background: #fff; width: 100%; max-width: 520px; margin: 0 auto; border-radius: 20px; padding: 22px; box-shadow: 0 18px 50px rgba(0, 0, 0, 0.22); text-align: left; }
.wx-top-guide { position: fixed; top: 14px; right: 16px; display: flex; align-items: center; gap: 8px; padding: 8px 11px; border-radius: 999px; background: rgba(255, 255, 255, 0.94); color: #111827; font-size: 12px; font-weight: 700; box-shadow: 0 10px 30px rgba(0, 0, 0, 0.18); }
.wx-top-arrow { font-size: 18px; line-height: 1; color: #007AFF; }
.wx-card-head { display: flex; gap: 12px; align-items: center; }
.wx-card-head img { width: 46px; height: 46px; border-radius: 11px; }
.wx-card-head h2 { margin: 0 0 5px; font-size: 21px; color: #111827; }
.wx-card-head p { margin: 0; font-size: 13px; color: #667085; }
.wx-steps { display: grid; gap: 12px; margin: 22px 0 18px; }
.wx-step { display: grid; gap: 5px; padding: 14px; border-radius: 14px; background: #F5F8FF; color: #344054; font-size: 14px; line-height: 1.55; }
.wx-step b { color: #007AFF; font-size: 14px; }
.wx-step strong { color: #111827; }
.wx-copy { width: 100%; min-height: 46px; border: 1px solid #D0D5DD; border-radius: 14px; background: #fff; color: #344054; font-size: 15px; font-weight: 700; cursor: pointer; }
.wx-copy-primary { border: 0; background: #007AFF; color: #fff; }
.wx-copy-tip { height: 16px; margin-top: 8px; color: #12B76A; font-size: 12px; text-align: center; opacity: 0; transition: opacity 0.2s ease; }
.wx-copy-tip.active { opacity: 1; }
.wx-close { display: block; width: 100%; margin-top: 12px; border: 0; background: transparent; font-size: 12px; color: #98A2B3; text-align: center; cursor: pointer; }


/* --- 完美移动端响应式断点控制 --- */
@media (max-width: 1024px) {
    .hero-main { flex-direction: column; text-align: center; gap: 40px; }
    .vocab-network { justify-content: center; }
    .hero-mockup { width: 100%; }
    .phone-case { max-width: 260px; margin: 0 auto; } /* 平板上缩减外壳，保持紧凑 */
    .shot-grid { grid-template-columns: repeat(2, 1fr); gap: 24px; }
    .town-feature { grid-template-columns: 1fr; padding: 40px 30px; gap: 40px; }
    .town-copy { text-align: center; }
    .town-showcase { max-width: 500px; margin: 0 auto; }
}

@media (max-width: 768px) {
    .navbar { padding: 15px 24px; }
    .hero { padding: 40px 24px 60px; }
    .hero-text h1 { font-size: 38px; }
    .gameplay-flow { padding: 60px 24px; }
    .section-title { font-size: 30px; margin-bottom: 40px; }
    .wx-mask { justify-content: center; align-items: center; padding: 20px; }
    .wx-card { width: 100%; }
}

@media (max-width: 480px) {
    .shot-grid { grid-template-columns: 1fr; }
    .town-showcase { grid-template-columns: 1fr; gap: 20px; }
    .town-phone { max-width: 170px; margin: 0 auto; } /* 极窄手机屏上确保外壳不拥挤 */
    .phone-case { max-width: 220px; }                 /* 首屏截图在小手机上安全缩放，绝不拉伸变形 */
    .hero-text h1 { font-size: 31px; }
    .btn-express { width: 100%; text-align: center; padding: 16px 20px; font-size: 16px; }
}