:root {
    --bg: #f6fbff;
    --panel: rgba(255,255,255,0.88);
    --panel-strong: #ffffff;
    --text: #0f1724;
    --accent: #6fb3ff;
    --accent-strong: #358df3;
    --muted: #6b7280;
    --radius: 18px;
    --shadow: 0 14px 35px rgba(23,43,77,0.10);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background:
        radial-gradient(circle at top, rgba(111,179,255,0.18), transparent 52%),
        linear-gradient(180deg, var(--bg), #ffffff 72%);
    color: var(--text);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    padding: 28px 20px 40px;
}

.container {
    max-width: 1120px;
    margin: 0 auto;
}

.tiktok-btn,
.primary-btn {
    display: inline-block;
    padding: 14px 38px;
    font-size: 16px;
    font-weight: 700;
    color: #fff;
    text-decoration: none;
    border-radius: var(--radius);
    background: linear-gradient(135deg, var(--accent), var(--accent-strong));
    box-shadow: 0 10px 25px rgba(111,179,255,0.28);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.tiktok-btn {
    position: relative;
    overflow: hidden;
}

.tiktok-btn::before {
    content: "";
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(255,255,255,0.22), transparent);
    pointer-events: none;
}

.tiktok-btn:hover,
.primary-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 14px 28px rgba(111,179,255,0.34);
}

.btn-secondary {
    display: inline-block;
    padding: 14px 24px;
    margin-left: 12px;
    border-radius: var(--radius);
    border: 1px solid rgba(111,179,255,0.22);
    color: var(--accent-strong);
    background: rgba(255,255,255,0.88);
    text-decoration: none;
    font-weight: 700;
    transition: transform 0.2s ease, background 0.2s ease;
}

.btn-secondary:hover {
    transform: translateY(-2px);
    background: #fff;
}

.hero {
    text-align: center;
    padding: 84px 24px 18px;
    background: var(--panel);
    border: 1px solid rgba(111,179,255,0.14);
    border-radius: 28px;
    box-shadow: var(--shadow);
    margin-bottom: 28px;
}

.hero p {
    font-size: 18px;
    max-width: 680px;
    margin: auto;
    color: var(--muted);
}

.app-intro-grid {
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    gap: 40px;
    align-items: center;
    text-align: left;
}

.app-meta {
    display: flex;
    align-items: center;
    gap: 18px;
    margin-bottom: 20px;
}

.app-icon {
    width: 86px;
    height: 86px;
    border-radius: 26px;
    background: linear-gradient(135deg, rgba(111,179,255,0.14), rgba(53,141,243,0.08));
    border: 1px solid rgba(111,179,255,0.22);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    font-weight: 800;
    letter-spacing: 1px;
    color: var(--accent-strong);
    box-shadow: 0 15px 35px rgba(111,179,255,0.18);
}

.app-icon img {
    width: 100%;
    height: 100%;
    border-radius: inherit;
    object-fit: cover;
}

.app-meta small {
    text-transform: uppercase;
    color: var(--muted);
    letter-spacing: 2px;
}

.app-meta h1 {
    margin: 5px 0 0;
    font-size: 26px;
}

.app-preview {
    position: relative;
    border-radius: 28px;
    padding: 18px;
    background: linear-gradient(135deg, rgba(111,179,255,0.12), rgba(255,255,255,0.9));
    border: 1px solid rgba(111,179,255,0.15);
    box-shadow: 0 26px 50px rgba(23,43,77,0.14);
    overflow: hidden;
}

.app-preview::after {
    content: "Hover 预览";
    position: absolute;
    top: 18px;
    right: 24px;
    font-size: 12px;
    letter-spacing: 1px;
    padding: 6px 12px;
    border-radius: 999px;
    border: 1px solid rgba(53,141,243,0.18);
    background: rgba(255,255,255,0.8);
    color: var(--accent-strong);
}

.app-preview img {
    width: 100%;
    border-radius: 22px;
    box-shadow: 0 18px 40px rgba(23,43,77,0.18);
    transition: transform 0.35s ease, box-shadow 0.35s ease;
}

.app-preview:hover img,
.app-preview:focus-within img {
    transform: scale(1.03);
    box-shadow: 0 24px 50px rgba(111,179,255,0.22);
}

.section-title {
    text-align: center;
    font-size: 34px;
    font-weight: 800;
    color: var(--text);
    margin-bottom: 40px;
}

.section {
    width: 100%;
    margin: auto;
    padding: 28px 0;
}

.features {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
}

.card {
    background: var(--panel-strong);
    padding: 26px;
    border-radius: var(--radius);
    border: 1px solid rgba(111,179,255,0.1);
    box-shadow: var(--shadow);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 18px 35px rgba(23,43,77,0.12);
}

.card h3 {
    font-size: 22px;
    margin-bottom: 10px;
    color: var(--accent-strong);
}

.gallery {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 25px;
    margin-top: 40px;
}

.gallery img {
    width: 100%;
    border-radius: var(--radius);
    border: 1px solid rgba(111,179,255,0.12);
    box-shadow: var(--shadow);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.gallery img:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 40px rgba(23,43,77,0.14);
}

.cta {
    text-align: center;
    padding: 80px 20px;
    background: linear-gradient(135deg, rgba(111,179,255,0.12), rgba(53,141,243,0.08));
    margin-top: 42px;
    border-radius: 28px;
    border: 1px solid rgba(111,179,255,0.12);
    box-shadow: var(--shadow);
}

.cta h2 {
    font-size: 36px;
    font-weight: 900;
    margin-bottom: 20px;
}

.corner-badge {
    position: fixed;
    top: 24px;
    left: 24px;
    z-index: 1000;
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 12px 18px;
    border-radius: 999px;
    background: rgba(255,255,255,0.8);
    border: 1px solid rgba(111,179,255,0.14);
    backdrop-filter: blur(10px);
    box-shadow: 0 20px 40px rgba(23,43,77,0.12);
}

.badge-text {
    display: flex;
    flex-direction: column;
    line-height: 1.2;
}

.badge-text strong {
    font-size: 15px;
    letter-spacing: 0.5px;
}

.badge-text small {
    font-size: 12px;
    color: var(--muted);
    letter-spacing: 1px;
    text-transform: uppercase;
}

@media (max-width: 900px) {
    .app-intro-grid {
        grid-template-columns: 1fr;
    }

    .features {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 640px) {
    .corner-badge {
        position: static;
        margin: 20px auto 0;
        justify-content: center;
        width: fit-content;
    }

    .features {
        grid-template-columns: 1fr;
    }

    .btn-secondary {
        display: block;
        margin: 12px 0 0;
    }
}