/* ===== Reset & Base ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary: #6366F1;
    --primary-deep: #4F46E5;
    --accent: #F43F5E;
    --bg: #F7F8FF;
    --bg-alt: #EEF0FB;
    --text: #171923;
    --text-soft: #5B6072;
    --card-border: #E4E6F4;
    --radius-lg: 24px;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg);
    color: var(--text);
    line-height: 1.6;
}

/* ===== 导航栏 ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(247, 248, 255, 0.92);
    backdrop-filter: blur(12px);
    z-index: 1000;
    padding: 0.9rem 0;
    border-bottom: 1px solid rgba(228, 230, 244, 0.7);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    color: var(--text);
    font-size: 1.4rem;
    font-weight: 800;
}

.logo-icon {
    display: inline-flex;
    align-items: center;
}

.logo-icon img {
    width: 30px;
    height: 30px;
    border-radius: 8px;
    display: block;
}

.footer-brand .logo-icon img {
    width: 24px;
    height: 24px;
    border-radius: 6px;
}

.hero-brand {
    display: flex;
    align-items: center;
    gap: 0.9rem;
    margin-bottom: 1.3rem;
}

.hero-brand img {
    width: 64px;
    height: 64px;
    border-radius: 16px;
    display: block;
    box-shadow: 0 8px 20px rgba(99, 102, 241, 0.18);
}

.hero-brand strong {
    display: block;
    font-size: 1.15rem;
    font-weight: 800;
    color: var(--text);
}

.hero-brand span {
    font-size: 0.85rem;
    color: var(--text-soft);
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-soft);
    font-size: 0.95rem;
    font-weight: 500;
    transition: color 0.3s;
}

.nav-links a:hover {
    color: var(--primary-deep);
}

.nav-actions {
    display: flex;
    gap: 1rem;
}

.btn {
    padding: 0.6rem 1.3rem;
    border-radius: 50px;
    text-decoration: none;
    font-size: 0.92rem;
    font-weight: 600;
    transition: all 0.3s;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    white-space: nowrap;
}

.btn-icon {
    width: 1.1em;
    height: 1.1em;
    margin-right: 0.45rem;
    flex-shrink: 0;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), #8B5CF6);
    color: #fff;
    box-shadow: 0 8px 20px rgba(99, 102, 241, 0.35);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 26px rgba(99, 102, 241, 0.45);
}

.btn-outline {
    border: 1.5px solid var(--card-border);
    color: var(--text);
    background: #fff;
}

/* 操作手册入口：弱化为朴素文字链，把视觉焦点留给「立即下载」 */
.btn-doc {
    padding: 0.4rem 0.25rem;
    background: transparent;
    border: none;
    border-radius: 8px;
    color: var(--text-soft);
    font-weight: 500;
    font-size: 0.88rem;
}

.btn-doc:hover {
    background: transparent;
    color: var(--primary-deep);
    text-decoration: underline;
}

.btn-outline:hover {
    border-color: var(--primary);
    color: var(--primary-deep);
}

.btn-lg {
    padding: 0.85rem 1.9rem;
    font-size: 1rem;
}

/* ===== Hero ===== */
.hero {
    padding: 9.5rem 0 5rem;
    overflow: hidden;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: grid;
    grid-template-columns: 1.05fr 1fr;
    align-items: center;
    gap: 3rem;
}

.hero-badge {
    display: inline-block;
    padding: 0.35rem 1rem;
    background: rgba(99, 102, 241, 0.1);
    color: var(--primary-deep);
    border-radius: 50px;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 1.4rem;
}

.hero-title {
    font-size: clamp(2.2rem, 4.5vw, 3.4rem);
    line-height: 1.25;
    font-weight: 800;
    letter-spacing: -0.5px;
}

.highlight {
    background: linear-gradient(120deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

/* 正文中的品牌名：品牌色 + 加粗，与周围文字区分 */
.brand {
    color: var(--primary-deep);
    font-weight: 700;
}

.hero-subtitle {
    margin-top: 1.3rem;
    font-size: 1.08rem;
    color: var(--text-soft);
    max-width: 34em;
}

.hero-actions {
    margin-top: 2.2rem;
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.hero-chips {
    margin-top: 2rem;
    display: flex;
    gap: 0.6rem;
    flex-wrap: wrap;
}

.hero-chips span {
    padding: 0.4rem 0.9rem;
    background: #fff;
    border: 1px solid var(--card-border);
    border-radius: 50px;
    font-size: 0.85rem;
    color: var(--text-soft);
}

/* Hero 视觉区 */
.hero-visual {
    position: relative;
    display: flex;
    justify-content: center;
    min-height: 560px;
    align-items: center;
}

/* 机身：金属渐变 + 内圈高光/暗边 + 分层阴影 */
.phone-mockup,
.shot-phone {
    background:
        linear-gradient(145deg,
            #4B5068 0%,
            #262935 14%,
            #171922 46%,
            #2F3342 78%,
            #454A60 100%);
    box-shadow:
        inset 0 0 0 1px rgba(255, 255, 255, 0.14),
        inset 0 0 2px rgba(255, 255, 255, 0.1),
        0 0 0 1px rgba(11, 12, 17, 0.9),
        0 2px 5px rgba(23, 25, 35, 0.14),
        0 16px 30px rgba(23, 25, 35, 0.13),
        0 42px 70px rgba(23, 25, 35, 0.14);
}

.phone-mockup {
    width: 300px;
    border-radius: 48px;
    padding: 9px 8px;
    position: relative;
    z-index: 2;
}

/* 侧边按键 */
.phone-mockup::before,
.shot-phone::before {
    content: '';
    position: absolute;
    right: -2px;
    top: 26%;
    width: 3px;
    height: 12%;
    border-radius: 0 3px 3px 0;
    background: linear-gradient(180deg, #4B5068, #22242F);
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.45);
}

.phone-mockup::after,
.shot-phone::after {
    content: '';
    position: absolute;
    left: -2px;
    top: 20%;
    width: 3px;
    height: 18%;
    border-radius: 3px 0 0 3px;
    background: linear-gradient(180deg, #4B5068, #22242F);
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.45);
}

.phone-screen {
    background: #F7F8FF;
    border-radius: 39px;
    overflow: hidden;
    position: relative;
    box-shadow: inset 0 0 12px rgba(23, 25, 35, 0.16);
}

.phone-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 22px 6px;
    font-size: 0.72rem;
    font-weight: 600;
}

.phone-notch {
    width: 80px;
    height: 20px;
    background: #171923;
    border-radius: 12px;
}

.phone-content {
    padding: 10px 16px 26px;
}

.phone-greeting {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 14px;
}

.greet-avatar {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, #E0E7FF, #FCE7F3);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.3rem;
}

.greet-avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 50%;
}

.phone-greeting h3 {
    font-size: 0.95rem;
    font-weight: 700;
}

.phone-greeting p {
    font-size: 0.72rem;
    color: #F59E0B;
    font-weight: 600;
}

.goal-card {
    background: linear-gradient(135deg, #6366F1, #8B5CF6);
    border-radius: 18px;
    padding: 16px;
    color: #fff;
    box-shadow: 0 14px 26px rgba(99, 102, 241, 0.35);
}

.goal-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.goal-label {
    font-size: 0.72rem;
    opacity: 0.9;
}

.goal-ring {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    border: 3px solid rgba(255, 255, 255, 0.35);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.68rem;
    font-weight: 700;
}

.goal-num {
    font-size: 0.9rem;
    margin: 8px 0 12px;
    opacity: 0.92;
}

.goal-num strong {
    font-size: 1.9rem;
    font-weight: 800;
}

.goal-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    background: rgba(255, 255, 255, 0.16);
    border-radius: 12px;
    padding: 8px 0;
    text-align: center;
}

.goal-stats div {
    display: flex;
    flex-direction: column;
    gap: 1px;
}

.goal-stats i {
    font-style: normal;
    font-size: 0.66rem;
    opacity: 0.85;
}

.goal-stats b {
    font-size: 0.95rem;
}

.phone-section {
    display: flex;
    justify-content: space-between;
    margin: 16px 0 10px;
    font-size: 0.76rem;
    font-weight: 700;
}

.phone-section span:last-child {
    color: #9CA0B5;
    font-weight: 500;
}

.deck-mini {
    display: flex;
    gap: 10px;
    background: #fff;
    border-radius: 14px;
    padding: 12px;
    box-shadow: 0 6px 16px rgba(23, 25, 35, 0.06);
}

.deck-mini-icon {
    width: 38px;
    height: 38px;
    background: #EEF0FF;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
}

.deck-mini-info {
    flex: 1;
}

.deck-mini-info strong {
    font-size: 0.78rem;
    display: block;
    margin-bottom: 6px;
}

.deck-bar {
    height: 5px;
    background: #EEF0FB;
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 5px;
}

.deck-bar span {
    display: block;
    width: 78%;
    height: 100%;
    background: linear-gradient(90deg, var(--primary), #8B5CF6);
    border-radius: 4px;
}

.deck-mini-info p {
    font-size: 0.66rem;
    color: #9CA0B5;
}

.phone-fab {
    position: absolute;
    bottom: 14px;
    left: 50%;
    transform: translateX(-50%);
    width: 44px;
    height: 44px;
    background: var(--accent);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.4rem;
    font-weight: 300;
    box-shadow: 0 10px 22px rgba(244, 63, 94, 0.45);
}

/* 浮动卡片 */
.floating-card {
    position: absolute;
    background: #fff;
    border: 1px solid var(--card-border);
    border-radius: 16px;
    padding: 0.9rem 1.1rem;
    display: flex;
    align-items: center;
    gap: 0.7rem;
    box-shadow: 0 16px 34px rgba(23, 25, 35, 0.1);
    z-index: 3;
    animation: float 5s ease-in-out infinite;
}

.float-icon {
    font-size: 1.4rem;
}

.float-text {
    display: flex;
    flex-direction: column;
    line-height: 1.35;
}

.float-text strong {
    font-size: 0.88rem;
}

.float-text span {
    font-size: 0.74rem;
    color: var(--text-soft);
}

.card-streak {
    top: 12%;
    left: -2%;
}

.card-retention {
    bottom: 20%;
    left: -4%;
    animation-delay: 1.6s;
}

.card-review {
    top: 32%;
    right: -3%;
    animation-delay: 3s;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-12px); }
}

/* ===== 通用 Section ===== */
.section {
    padding: 5.5rem 0;
}

.section-alt {
    background: var(--bg-alt);
}

.section-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

.section-head {
    text-align: center;
    max-width: 720px;
    margin: 0 auto 3.2rem;
}

.section-tag {
    display: inline-block;
    padding: 0.3rem 1rem;
    background: rgba(99, 102, 241, 0.1);
    color: var(--primary-deep);
    border-radius: 50px;
    font-size: 0.82rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.section-head h2,
.split-copy h2 {
    font-size: clamp(1.7rem, 3vw, 2.3rem);
    font-weight: 800;
    line-height: 1.35;
}

.section-head p {
    margin-top: 0.9rem;
    color: var(--text-soft);
    font-size: 1.02rem;
}

/* 功能总览网格 */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.4rem;
}

.feature-card {
    background: #fff;
    border: 1px solid var(--card-border);
    border-radius: var(--radius-lg);
    padding: 1.8rem;
    transition: transform 0.3s, box-shadow 0.3s;
}

.feature-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 18px 40px rgba(23, 25, 35, 0.09);
}

.feature-icon {
    width: 52px;
    height: 52px;
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    margin-bottom: 1.1rem;
}

.f-purple { background: #EEF0FF; }
.f-pink   { background: #FFE9EE; }
.f-blue   { background: #E4F0FF; }
.f-orange { background: #FFF1E0; }
.f-green  { background: #E4F8EC; }
.f-cyan   { background: #E0F7FA; }

.feature-card h3 {
    font-size: 1.12rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.feature-card p {
    color: var(--text-soft);
    font-size: 0.93rem;
}

/* ===== 左右分栏展示 ===== */
.split {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.split-reverse {
    direction: rtl;
}

.split-reverse > * {
    direction: ltr;
}

.split-copy p {
    margin-top: 1.1rem;
    color: var(--text-soft);
    font-size: 1.02rem;
}

.split-visual {
    display: flex;
    justify-content: center;
    gap: 1.4rem;
}

/* 截图手机外壳：裁掉系统状态栏，只展示 App 内容 */
.shot-phone {
    position: relative;
    margin: 0;
    width: 272px;
    flex-shrink: 0;
    padding: 8px;
    border-radius: 44px;
}

.shot-phone.sm {
    width: 232px;
}

.shot-screen {
    position: relative;
    border-radius: 37px;
    overflow: hidden;
    background: #fff;
    box-shadow: inset 0 0 12px rgba(23, 25, 35, 0.16);
    /* 截图 2160x3840，裁去顶部 114px 状态栏 */
    aspect-ratio: 2160 / 3726;
}

/* 屏幕斜向光泽 */
.shot-screen::after {
    content: '';
    position: absolute;
    inset: 0;
    pointer-events: none;
    background: linear-gradient(118deg,
        rgba(255, 255, 255, 0.18) 0%,
        rgba(255, 255, 255, 0.02) 24%,
        rgba(255, 255, 255, 0) 46%,
        rgba(255, 255, 255, 0) 74%,
        rgba(255, 255, 255, 0.07) 100%);
}

.shot-screen img {
    display: block;
    width: 100%;
    /* 114 / 2160，按容器宽度换算的裁切量 */
    margin-top: -5.278%;
}

/* 手势列表 */
.gesture-list {
    list-style: none;
    margin-top: 1.6rem;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.9rem;
}

.gesture-list li {
    display: flex;
    align-items: center;
    gap: 0.7rem;
    background: #fff;
    border: 1px solid var(--card-border);
    border-radius: 12px;
    padding: 0.7rem 1rem;
    font-size: 0.92rem;
    font-weight: 600;
}

/* 手势环绕：学习卡片四周的四向滑动标注 */
.gesture-ring {
    position: relative;
    padding: 3.2rem 0;
}

/* 学习卡片组：替代第二部手机，避免连续手机观感 */
.study-deck {
    position: relative;
    width: 300px;
    flex-shrink: 0;
}

.study-stack {
    position: relative;
    height: 348px;
}

.study-card {
    position: absolute;
    inset: 0;
    background: #fff;
    border: 1px solid var(--card-border);
    border-radius: var(--radius-lg);
    box-shadow: 0 18px 40px rgba(23, 25, 35, 0.12);
    padding: 1.6rem 1.5rem;
    display: flex;
    flex-direction: column;
}

.study-card-tail {
    transform: rotate(-8deg) translate(-30px, 22px);
    opacity: 0.5;
}

.study-card-mid {
    transform: rotate(-4deg) translate(-15px, 11px);
    opacity: 0.8;
}

.study-card-front {
    transform: rotate(2deg);
}

.study-deck-tag {
    align-self: flex-start;
    padding: 0.25rem 0.75rem;
    border-radius: 50px;
    background: rgba(99, 102, 241, 0.1);
    color: var(--primary-deep);
    font-size: 0.78rem;
    font-weight: 600;
}

.study-answer {
    margin-top: 1.2rem;
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text-soft);
}

.study-side {
    margin-top: 1.4rem;
    font-size: 0.78rem;
    letter-spacing: 1px;
    color: var(--text-soft);
}

.study-question {
    margin-top: 0.4rem;
    font-size: 2rem;
    font-weight: 800;
    line-height: 1.3;
}

.study-hint {
    margin-top: 0.8rem;
    font-size: 0.9rem;
    color: var(--text-soft);
}

.study-foot {
    margin-top: auto;
    padding-top: 1rem;
    border-top: 1px dashed var(--card-border);
    display: flex;
    justify-content: space-between;
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--text-soft);
}

.swipe-chips {
    position: absolute;
    inset: -1.7rem -1.2rem;
}

.swipe-chip {
    position: absolute;
    display: flex;
    align-items: center;
    gap: 0.55rem;
    padding: 0.4rem 0.95rem 0.4rem 0.4rem;
    background: #fff;
    border: 1px solid var(--card-border);
    border-radius: 50px;
    box-shadow: 0 14px 28px rgba(23, 25, 35, 0.1);
    font-size: 0.88rem;
    font-weight: 600;
    white-space: nowrap;
    z-index: 3;
}

.swipe-chip .gesture {
    width: 26px;
    height: 26px;
    font-size: 0.85rem;
    font-weight: 700;
}

.chip-left  { top: 38%; left: 0; }
.chip-right { top: 38%; right: 0; }
.chip-up    { top: 0; left: 50%; transform: translateX(-50%); }
.chip-down  { bottom: 0; left: 50%; transform: translateX(-50%); }

@media (max-width: 960px) {
    .gesture-ring {
        flex-direction: column;
        align-items: center;
        padding: 0;
    }

    /* 单列排版不再环绕，手势信息由文案侧列表承载 */
    .swipe-chips {
        display: none;
    }
}

.gesture {
    width: 30px;
    height: 30px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.95rem;
    color: #fff;
    flex-shrink: 0;
}

.g-left  { background: #F43F5E; }
.g-right { background: #22C55E; }
.g-up    { background: #F59E0B; }
.g-down  { background: #3B82F6; }

/* AI 来源 */
.ai-sources {
    margin-top: 1.6rem;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.9rem;
}

.source-item {
    display: flex;
    gap: 0.8rem;
    background: #fff;
    border: 1px solid var(--card-border);
    border-radius: 14px;
    padding: 0.9rem 1rem;
}

.source-item span {
    font-size: 1.3rem;
}

.source-item strong {
    font-size: 0.92rem;
    display: block;
}

.source-item p {
    font-size: 0.78rem;
    color: var(--text-soft);
    margin: 0;
}

/* AI 段：主次叠放 + 身份标注 */
.ai-stack {
    position: relative;
    width: 100%;
    max-width: 446px;
    padding: 3.4rem 0 3.2rem;
}

.ai-main {
    margin-left: auto;
}

.ai-sub.sm {
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 200px;
    border: 5px solid var(--bg);
    border-radius: 49px;
    filter: drop-shadow(0 20px 34px rgba(23, 25, 35, 0.18));
    z-index: 2;
}

.ai-badge {
    position: absolute;
    display: flex;
    align-items: center;
    gap: 0.45rem;
    padding: 0.4rem 0.85rem;
    background: #fff;
    border: 1px solid var(--card-border);
    border-radius: 50px;
    box-shadow: 0 12px 26px rgba(23, 25, 35, 0.1);
    font-size: 0.82rem;
    font-weight: 600;
    white-space: nowrap;
    z-index: 3;
}

.badge-main { top: 0; right: 0; }
.badge-sub  { bottom: 0; left: 0; }

.rec-dot {
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: #F43F5E;
    box-shadow: 0 0 0 3px rgba(244, 63, 94, 0.16);
}

@media (max-width: 1160px) {
    .ai-stack {
        display: flex;
        flex-direction: column;
        align-items: center;
        gap: 1.2rem;
        max-width: none;
        padding: 0;
    }

    .ai-main {
        margin-left: 0;
    }

    .ai-sub.sm {
        position: relative;
        top: auto;
        left: auto;
        transform: none;
        border: 0;
    }

    /* 窄屏叠放解除，标注不再重复文案信息 */
    .ai-badge {
        display: none;
    }
}

/* 统计指标 chips */
.metric-chips {
    margin-top: 1.6rem;
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
}

.metric-chips span {
    padding: 0.5rem 1rem;
    background: #fff;
    border: 1px solid var(--card-border);
    border-radius: 50px;
    font-size: 0.88rem;
    font-weight: 500;
}

/* 学习统计：柔光环装饰 + 上下贴边标注 */
.stats-stage {
    position: relative;
}

.stats-stack {
    position: relative;
    padding: 3.3rem 0;
}

.stats-glow {
    position: absolute;
    top: 50%;
    left: 50%;
    width: 460px;
    height: 460px;
    margin: -230px 0 0 -230px;
    background: radial-gradient(circle, rgba(99, 102, 241, 0.13), rgba(99, 102, 241, 0) 68%);
    pointer-events: none;
}

.stats-ring {
    position: absolute;
    top: 50%;
    left: 50%;
    width: 372px;
    height: 372px;
    margin: -186px 0 0 -186px;
    border: 1.5px dashed rgba(99, 102, 241, 0.3);
    border-radius: 50%;
    pointer-events: none;
}

.stat-pill {
    position: absolute;
    display: flex;
    align-items: center;
    gap: 0.45rem;
    padding: 0.42rem 0.9rem;
    background: #fff;
    border: 1px solid var(--card-border);
    border-radius: 50px;
    box-shadow: 0 14px 28px rgba(23, 25, 35, 0.1);
    font-size: 0.84rem;
    font-weight: 600;
    white-space: nowrap;
    z-index: 3;
}

.pill-tabs {
    top: 0;
    left: 50%;
    transform: translateX(-50%);
}

.pill-stubborn {
    bottom: 0;
    right: 0;
}

@media (max-width: 960px) {
    .stats-stack {
        padding: 0;
    }

    .stats-glow {
        width: 340px;
        height: 340px;
        margin: -170px 0 0 -170px;
    }

    .stats-ring {
        width: 300px;
        height: 300px;
        margin: -150px 0 0 -150px;
    }

    .stat-pill {
        display: none;
    }
}

/* 对战 + 广场 双卡 */
.duo-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.6rem;
}

.duo-card {
    background: #fff;
    border: 1px solid var(--card-border);
    border-radius: var(--radius-lg);
    padding: 2rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
    transition: transform 0.3s, box-shadow 0.3s;
}

.duo-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 18px 40px rgba(23, 25, 35, 0.09);
}

.duo-info h3 {
    font-size: 1.15rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.duo-info p {
    color: var(--text-soft);
    font-size: 0.93rem;
}

/* 对战卡：淡淡靛蓝底 + 靛蓝点缀，保持站点色系 */
.duo-card--battle {
    background: linear-gradient(180deg, rgba(99, 102, 241, 0.07) 0%, rgba(99, 102, 241, 0.02) 100%);
    border-color: rgba(99, 102, 241, 0.2);
}

/* 卡内小标注 */
.duo-badge {
    position: relative;
    z-index: 1;
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.35rem 0.85rem;
    border-radius: 50px;
    font-size: 0.8rem;
    font-weight: 600;
    background: #F4F5FD;
    border: 1px solid var(--card-border);
    color: var(--text-soft);
}

.duo-card--battle .duo-badge {
    background: rgba(99, 102, 241, 0.1);
    border-color: rgba(99, 102, 241, 0.26);
    color: var(--primary-deep);
}

.duo-info {
    position: relative;
    z-index: 1;
}

.duo-tags {
    position: relative;
    z-index: 1;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.5rem;
}

.duo-tags span {
    padding: 0.3rem 0.75rem;
    border-radius: 50px;
    font-size: 0.78rem;
    font-weight: 600;
    background: #F4F5FD;
    border: 1px solid var(--card-border);
    color: var(--text-soft);
}

.duo-card--battle .duo-tags span {
    background: rgba(99, 102, 241, 0.08);
    border-color: rgba(99, 102, 241, 0.22);
    color: var(--primary-deep);
}

/* 五个玩法排成 3+2，避免最后剩一个落单 */
.duo-card--battle .duo-tags {
    max-width: 380px;
}

/* 导入段：Anki 卡包搬进手机 */
.import-flow {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.6rem;
}

.import-flow .shot-phone {
    width: 250px;
}

.apkg-file {
    flex-shrink: 0;
    width: 124px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.28rem;
    padding: 0.75rem 0.55rem;
    background: #fff;
    border: 1px solid var(--card-border);
    border-radius: 16px;
    box-shadow: 0 14px 28px rgba(23, 25, 35, 0.1);
    text-align: center;
}

.apkg-icon {
    display: grid;
    place-items: center;
    width: 34px;
    height: 34px;
    margin-bottom: 0.15rem;
    border-radius: 10px;
    background: rgba(99, 102, 241, 0.1);
    font-size: 1rem;
}

.apkg-file strong {
    width: 100%;
    font-size: 0.76rem;
    font-weight: 700;
    line-height: 1.35;
}

.apkg-note {
    width: 100%;
    font-size: 0.66rem;
    line-height: 1.4;
    color: var(--text-soft);
}

/* 虚线连接线 + 箭头，读作「搬进来」 */
.apkg-arrow {
    flex-shrink: 0;
    position: relative;
    width: 44px;
    height: 2px;
    background: repeating-linear-gradient(90deg,
        rgba(99, 102, 241, 0.55) 0 4px,
        transparent 4px 9px);
}

.apkg-arrow::after {
    content: '';
    position: absolute;
    right: 0;
    top: 50%;
    width: 7px;
    height: 7px;
    border-top: 2px solid rgba(99, 102, 241, 0.55);
    border-right: 2px solid rgba(99, 102, 241, 0.55);
    transform: translateY(-50%) rotate(45deg);
}

/* 两列收窄到 1024 及以下时，手机缩一档避免文件卡把宽度撑满 */
@media (max-width: 1024px) {
    .import-flow .shot-phone {
        width: 224px;
    }
}

@media (max-width: 640px) {
    .import-flow {
        flex-direction: column;
        gap: 0.7rem;
    }

    .apkg-arrow {
        width: 2px;
        height: 34px;
        background: repeating-linear-gradient(180deg,
            rgba(99, 102, 241, 0.55) 0 4px,
            transparent 4px 9px);
    }

    .apkg-arrow::after {
        right: 50%;
        top: auto;
        bottom: 0;
        transform: translateX(50%) rotate(135deg);
    }
}

/* ===== 下载区域 ===== */
/* 深色只保留在两张卡片上：区块底与 .section-alt 同族浅紫，上下与相邻区块同色，无硬切边 */
.download-section {
    position: relative;
    overflow: hidden;
    padding: 5rem 0 5.5rem;
    background: linear-gradient(180deg, #EEF0FB 0%, #F3F1FE 45%, #EEF0FB 100%);
}

/* 淡紫网点，保留氛围但不抢内容 */
.download-section::before {
    content: "";
    position: absolute;
    inset: 0;
    background-image: radial-gradient(rgba(99, 102, 241, 0.09) 1px, transparent 1px);
    background-size: 24px 24px;
    -webkit-mask-image: radial-gradient(720px 460px at 50% 42%, #000 0%, transparent 78%);
    mask-image: radial-gradient(720px 460px at 50% 42%, #000 0%, transparent 78%);
    pointer-events: none;
}

.download-container {
    position: relative;
    z-index: 1;
    max-width: 820px;
    margin: 0 auto;
    padding: 0 2rem;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.6rem;
}

.download-container .section-head {
    grid-column: 1 / -1;
    margin-bottom: 0.6rem;
}

/* 卡片承接深色：低饱和雾蓝渐变 + 白色内描边 + 投影，在浅底上浮起 */
.download-card {
    display: flex;
    flex-direction: column;
    color: #fff;
    background: linear-gradient(160deg, #5E76B3 0%, #4D62A0 55%, #40548C 100%);
    border: 1px solid rgba(255, 255, 255, 0.14);
    border-radius: 16px;
    padding: 1.5rem 1.4rem;
    text-align: center;
    box-shadow: 0 20px 45px rgba(28, 38, 60, 0.28), inset 0 1px 0 rgba(255, 255, 255, 0.18);
}

.download-card-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.8rem;
    padding-bottom: 0.9rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.14);
}

.platform-title {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.status-pill {
    display: inline-flex;
    align-items: center;
    padding: 0.24rem 0.7rem;
    border-radius: 999px;
    font-size: 0.74rem;
    font-weight: 600;
    white-space: nowrap;
}

/* 待上线：半透明白底 + 浅白字，中性弱化 */
.status-pill--pending {
    background: rgba(255, 255, 255, 0.16);
    border: 1px solid rgba(255, 255, 255, 0.22);
    color: rgba(255, 255, 255, 0.82);
}

/* 可下载：白底 + 品牌紫字，卡片内最亮元素，一眼可辨 */
.status-pill--available {
    background: #fff;
    border: 1px solid rgba(255, 255, 255, 0.6);
    color: var(--primary-deep);
    box-shadow: 0 4px 12px rgba(28, 38, 60, 0.25);
}

/* 上紧下松：主体贴住分割线，剩余留白交给底部备注 */
.download-card-body {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
    padding: 1.5rem 0 1.2rem;
}

.download-card-footer {
    margin-top: auto;
}

.qr-wrapper {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.7rem;
}

.qr-hint {
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.9);
}

/* 二维码衬底：冷灰蓝白而非纯白，与雾蓝背景柔和过渡 */
.qr-code {
    width: 168px;
    height: 168px;
    background: #EEF3F8;
    border-radius: 14px;
    padding: 14px;
    box-shadow: 0 12px 26px rgba(28, 38, 60, 0.24), inset 0 1px 0 rgba(255, 255, 255, 0.9);
}

.qr-trigger {
    border: none;
    display: block;
    cursor: zoom-in;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.qr-trigger:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 24px rgba(15, 23, 42, 0.25);
}

.qr-img {
    display: block;
    width: 100%;
    height: 100%;
    object-fit: contain;
}

/* iOS 尚未上架：进度环 + 主标题，视觉重量与 Android 二维码区保持一致 */
.ios-ring {
    display: grid;
    place-items: center;
    width: 62px;
    height: 62px;
    margin-bottom: 1.1rem;
    border-radius: 18px;
    background: rgba(255, 255, 255, 0.14);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.ios-ring svg {
    display: block;
    width: 36px;
    height: 36px;
    fill: none;
    stroke: #fff;
    stroke-width: 2.4;
    stroke-linecap: round;
}

.ios-ring .ring-track {
    stroke: rgba(255, 255, 255, 0.24);
}

.ios-ring .ring-progress {
    stroke-dasharray: 113;
    stroke-dashoffset: 45;
    transform: rotate(-90deg);
    transform-origin: 22px 22px;
}

/* 模块主标题：页面内最高优先级 */
.card-lead {
    display: block;
    font-size: 1.375rem;
    font-weight: 700;
    line-height: 1.35;
}

.card-text {
    margin-top: 0.5rem;
    font-size: 0.875rem;
    line-height: 1.6;
    color: rgba(255, 255, 255, 0.85);
}

/* iOS 暂不可下载：明确的禁用态，避免误导点击 */
.btn-disabled {
    display: flex;
    width: 100%;
    min-height: 74px;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.2rem;
    padding: 0.9rem 1.1rem;
    border: 1px solid rgba(255, 255, 255, 0.22);
    border-radius: 12px;
    background: rgba(255, 255, 255, 0.07);
    color: rgba(255, 255, 255, 0.7);
    cursor: not-allowed;
}

.btn-disabled span {
    font-size: 0.95rem;
    font-weight: 600;
}

.btn-disabled small {
    font-size: 0.75rem;
    color: rgba(255, 255, 255, 0.6);
}

/* Android APK 直链下载（核心 CTA，PC 与 Android 均显示，二维码仅 PC 显示） */
.apk-download {
    display: flex;
    width: 100%;
    min-height: 74px;
    padding: 0.9rem 1.1rem;
    background: linear-gradient(135deg, #6366F1, #8B5CF6);
    border: 1px solid rgba(255, 255, 255, 0.32);
    border-radius: 12px;
    flex-direction: row;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    color: #fff;
    text-decoration: none;
    box-shadow: 0 14px 28px rgba(35, 27, 88, 0.5);
    transition: transform 0.2s ease, box-shadow 0.2s ease, filter 0.2s ease;
}

.apk-download:hover {
    transform: translateY(-2px);
    filter: brightness(1.07);
    box-shadow: 0 18px 34px rgba(43, 34, 96, 0.55);
}

/* 移动端没有 hover，按下时给一次可见反馈 */
.apk-download:active {
    transform: scale(0.985);
    filter: brightness(0.97);
}

/* 已触发下载：短暂禁用，避免重复点击 */
.apk-download.is-loading {
    pointer-events: none;
    opacity: 0.72;
}

.apk-download-icon {
    width: 1.7rem;
    height: 1.7rem;
    flex-shrink: 0;
}

.apk-download-text {
    display: flex;
    flex-direction: column;
    gap: 0.2rem;
}

.apk-download strong {
    font-size: 1.125rem;
    font-weight: 700;
}

.apk-download small {
    font-size: 0.8rem;
    line-height: 1.4;
    color: rgba(255, 255, 255, 0.82);
}

.only-android {
    display: none;
}

/* Android 端不显示二维码（已能直接下载），同时收掉二维码区留下的间距 */
html.is-android .android-card .qr-wrapper {
    display: none;
}

html.is-android .android-card .download-card-body {
    display: none;
}

html.is-android .android-card .only-pc {
    display: none;
}

html.is-android .android-card .only-android {
    display: inline;
}

/* ===== 二维码放大预览 ===== */
.qr-modal {
    position: fixed;
    inset: 0;
    z-index: 1200;
    display: none;
    align-items: center;
    justify-content: center;
    padding: 1.5rem;
}

.qr-modal.is-open {
    display: flex;
}

.qr-modal-mask {
    position: absolute;
    inset: 0;
    background: rgba(15, 23, 42, 0.72);
    backdrop-filter: blur(4px);
}

.qr-modal-body {
    position: relative;
    background: #fff;
    border-radius: 20px;
    padding: 1.3rem;
    text-align: center;
    box-shadow: 0 24px 60px rgba(0, 0, 0, 0.35);
}

.qr-modal-img {
    display: block;
    width: min(70vw, 320px);
    height: auto;
    border-radius: 8px;
}

.qr-modal-caption {
    margin-top: 0.8rem;
    font-size: 0.9rem;
    color: var(--text-soft);
}

.qr-modal-close {
    position: absolute;
    top: -14px;
    right: -14px;
    width: 34px;
    height: 34px;
    border: none;
    border-radius: 50%;
    background: #fff;
    color: var(--text);
    font-size: 1.25rem;
    line-height: 1;
    cursor: pointer;
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.22);
}

.qr-modal-close:hover {
    color: var(--primary);
}

/* 卡片标题：18px 加粗 */
.platform-name {
    font-size: 1.125rem;
    font-weight: 700;
    margin: 0;
}

/* 品牌图标统一为面性风格，尺寸一致 */
.platform-icon {
    width: 1.2rem;
    height: 1.2rem;
    flex-shrink: 0;
}

/* 底部备注：12~13px，降低透明度，不抢视觉 */
.platform-desc {
    margin-top: 0.6rem;
    font-size: 0.8rem;
    line-height: 1.5;
    color: rgba(255, 255, 255, 0.68);
}

/* ===== 下载中转页（download.html） ===== */
.dl-body {
    min-height: 100vh;
    background: linear-gradient(160deg, #5E76B3, #4D62A0 55%, #40548C);
    color: #fff;
}

.dl-page {
    max-width: 420px;
    margin: 0 auto;
    padding: 4rem 2rem;
    text-align: center;
}

.dl-logo img {
    width: 64px;
    height: 64px;
}

.dl-title {
    margin-top: 0.8rem;
    font-size: 1.5rem;
    font-weight: 800;
}

.dl-msg {
    margin-top: 0.6rem;
    font-size: 0.95rem;
    color: rgba(255, 255, 255, 0.88);
}

.dl-btn {
    display: inline-block;
    margin-top: 2rem;
    border-radius: 50px;
    padding: 0.7rem 2rem;
    background: #fff;
    color: var(--primary);
    font-weight: 600;
    text-decoration: none;
}

.dl-qr {
    margin-top: 1.6rem;
}

.dl-qr img {
    width: 180px;
    height: 180px;
    padding: 12px;
    background: #fff;
    border-radius: 16px;
}

.dl-qr p {
    margin-top: 0.7rem;
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.85);
}

.dl-back {
    display: inline-block;
    margin-top: 2.2rem;
    font-size: 0.88rem;
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
}

.dl-back:hover {
    color: #fff;
    text-decoration: underline;
}

/* ===== 微信内置浏览器下载引导 ===== */
.browser-guide {
    position: fixed;
    inset: 0;
    z-index: 1300;
    display: none;
}

.browser-guide.is-open {
    display: block;
}

.browser-guide-mask {
    position: absolute;
    inset: 0;
    background: rgba(15, 23, 42, 0.88);
}

.browser-guide-arrow {
    position: absolute;
    top: 0.3rem;
    right: 1.2rem;
    font-size: 2.6rem;
    line-height: 1;
    color: #fff;
}

.browser-guide-body {
    position: relative;
    padding: 7rem 2rem 0;
    text-align: center;
    color: #fff;
}

.browser-guide-title {
    font-size: 1.25rem;
    font-weight: 700;
}

.browser-guide-steps {
    margin-top: 0.8rem;
    font-size: 0.95rem;
    line-height: 2;
    color: rgba(255, 255, 255, 0.88);
}

.browser-guide-steps .dots {
    display: inline-block;
    padding: 0 0.4rem;
    border-radius: 6px;
    background: rgba(255, 255, 255, 0.18);
    font-weight: 700;
}

.browser-guide-copy {
    margin-top: 2rem;
    border: none;
    border-radius: 50px;
    padding: 0.6rem 1.6rem;
    background: #fff;
    color: var(--primary);
    font-size: 0.92rem;
    font-weight: 600;
    cursor: pointer;
}

.browser-guide-copy.is-copied {
    background: var(--primary);
    color: #fff;
}

.browser-guide-tip {
    margin-top: 0.9rem;
    font-size: 0.8rem;
    color: rgba(255, 255, 255, 0.72);
}

/* 复制失败时的兜底：露出地址供长按选择 */
.browser-guide-link {
    margin-top: 0.9rem;
    padding: 0.7rem 0.9rem;
    border-radius: 10px;
    background: rgba(255, 255, 255, 0.12);
    font-size: 0.8rem;
    line-height: 1.5;
    word-break: break-all;
    user-select: all;
}

/* ===== 页脚 ===== */
.footer {
    padding: 2.6rem 0;
    background: #F0F1FA;
    text-align: center;
}

.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

.footer-brand {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.2rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
}

.footer-note {
    color: var(--text-soft);
    font-size: 0.88rem;
    margin-bottom: 0.4rem;
}

.footer p:last-child {
    color: #9CA0B5;
    font-size: 0.82rem;
}

.footer-beian {
    margin-left: 0.9rem;
    color: inherit;
    text-decoration: none;
}

.footer-beian:hover {
    text-decoration: underline;
}

.footer-gaba {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    vertical-align: middle;
    white-space: nowrap;
}

.footer-gaba img {
    display: block;
    width: 14px;
    height: 14px;
}

/* ===== 移动端导航与汉堡按钮 ===== */
.nav-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 36px;
    height: 36px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 4px;
    border-radius: 8px;
    transition: background-color 0.2s;
}

.nav-toggle span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--text);
    border-radius: 2px;
    transition: transform 0.25s, opacity 0.25s;
    margin: 0 auto;
}

.nav-toggle.is-active span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.nav-toggle.is-active span:nth-child(2) {
    opacity: 0;
}

.nav-toggle.is-active span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

.mobile-nav-menu {
    display: none;
}

/* ===== 响应式 ===== */
@media (max-width: 960px) {
    .nav-links {
        display: none;
    }

    .nav-toggle {
        display: flex;
    }

    .mobile-nav-menu {
        display: block;
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.35s ease, padding 0.3s ease;
        background: #fff;
        border-top: 1px solid var(--card-border);
        box-shadow: 0 16px 30px rgba(23, 25, 35, 0.08);
        padding: 0 1.5rem;
    }

    .mobile-nav-menu.is-open {
        max-height: 80vh;
        overflow-y: auto;
        padding: 1.2rem 1.5rem 1.8rem;
    }

    .mobile-nav-menu a {
        display: block;
        padding: 0.75rem 0.5rem;
        color: var(--text);
        text-decoration: none;
        font-size: 1rem;
        font-weight: 600;
        border-bottom: 1px solid rgba(228, 230, 244, 0.6);
        transition: color 0.2s;
    }

    .mobile-nav-menu a:hover {
        color: var(--primary);
    }

    .mobile-nav-actions {
        display: flex;
        flex-direction: column;
        gap: 0.8rem;
        margin-top: 1.2rem;
    }

    .mobile-nav-actions .btn {
        width: 100%;
        text-align: center;
    }

    .hero {
        padding-top: 7rem;
    }

    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-subtitle {
        margin-left: auto;
        margin-right: auto;
    }

    .hero-actions,
    .hero-chips {
        justify-content: center;
    }

    .hero-visual {
        min-height: 0;
        margin-top: 2rem;
    }

    .floating-card {
        display: none;
    }

    .feature-grid,
    .duo-grid,
    .split {
        grid-template-columns: 1fr;
    }

    .split {
        gap: 2.5rem;
    }

    /* 单列时收窄双卡，避免满屏渐变里一台小手机 */
    .duo-card {
        width: 100%;
        max-width: 520px;
        margin: 0 auto;
    }

    .split-visual {
        flex-wrap: wrap;
        justify-content: center;
    }
}

/* 移动端下载双卡：上下堆叠，iOS 在上、Android 在下 */
@media (max-width: 768px) {
    .download-container {
        grid-template-columns: 1fr;
        max-width: 460px;
    }

    .download-section {
        padding: 4rem 0 4.5rem;
    }
}

@media (max-width: 640px) {
    .nav-actions .btn {
        display: none;
    }

    .hero-title {
        font-size: 2.1rem;
    }

    .hero-actions {
        flex-direction: column;
        width: 100%;
    }

    .hero-actions .btn {
        width: 100%;
    }

    .phone-mockup {
        width: min(290px, 86vw);
    }

    /* 窄屏收敛卡片扇形幅度，避免旋转卡片溢出视口 */
    .study-deck {
        width: min(260px, 82vw);
    }

    .study-stack {
        height: 300px;
    }

    .study-card-tail {
        transform: rotate(-6deg) translate(-10px, 14px);
    }

    .study-card-mid {
        transform: rotate(-3deg) translate(-5px, 7px);
    }
}

@media (max-width: 520px) {
    .nav-container {
        padding: 0 1.2rem;
    }

    .section-container,
    .download-container,
    .hero-container {
        padding: 0 1.2rem;
    }

    .gesture-list,
    .ai-sources {
        grid-template-columns: 1fr;
    }

    .shot-phone,
    .shot-phone.sm {
        width: 224px;
        max-width: 82vw;
    }

    .download-card {
        padding: 1.5rem 1rem;
    }

    /* 窄屏保持主次比例，次图不与主图等大 */
    .ai-stack .ai-sub.sm {
        width: 176px;
    }

    /* 窄屏道具标签收紧，避免 3+1 断行 */
    .duo-tags {
        gap: 0.35rem;
    }

    .duo-tags span {
        padding: 0.28rem 0.56rem;
        font-size: 0.72rem;
    }
}

/* 超窄屏收敛统计段装饰尺寸，避免横向溢出 */
@media (max-width: 400px) {
    .stats-glow {
        width: 270px;
        height: 270px;
        margin: -135px 0 0 -135px;
    }

    .stats-ring {
        width: 250px;
        height: 250px;
        margin: -125px 0 0 -125px;
    }
}