/* Lule Zhihu - Official Website Style (ROLO) */
:root {
    --primary: #007AFF;
    --accent: #00F2FE;
    --bg: #030303;
    --surface: rgba(255, 255, 255, 0.05);
    --surface-border: rgba(255, 255, 255, 0.1);
    --text-main: #ffffff;
    --text-dim: #a1a1a1;
    --glass: blur(12px);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

body {
    background-color: var(--bg);
    color: var(--text-main);
    line-height: 1.6;
    overflow-x: hidden;
    scroll-behavior: smooth;
}

/* Typography */
h1, h2, h3 {
    font-weight: 700;
    letter-spacing: -0.02em;
}

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

section {
    padding: 100px 0;
}

/* Navbar */
nav {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    background: rgba(3, 3, 3, 0.7);
    backdrop-filter: var(--glass);
    border-bottom: 1px solid var(--surface-border);
    padding: 1rem 0;
}

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

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

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

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

.nav-links a:hover {
    color: var(--text-main);
}

/* Mobile nav toggle button */
.nav-toggle {
    display: none;
    background: transparent;
    border: none;
    color: var(--text-main);
    font-weight: 700;
    cursor: pointer;
    padding: 0.4rem 0.6rem;
    border-radius: 12px;
}

.nav-toggle:focus-visible {
    outline: 2px solid rgba(0, 122, 255, 0.7);
    outline-offset: 2px;
}

/* Hero Section */
.hero {
    height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    padding-top: 80px;
    background: radial-gradient(circle at 10% 20%, rgba(0, 122, 255, 0.1) 0%, transparent 40%);
}

.hero-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-content h1 {
    font-size: 4.5rem;
    line-height: 1.1;
    margin-bottom: 1.5rem;
}

.hero-content p {
    font-size: 1.25rem;
    color: var(--text-dim);
    margin-bottom: 2.5rem;
}

.hero-visual {
    position: relative;
}

.hero-image {
    width: 100%;
    border-radius: 2rem;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 1rem 2.5rem;
    border-radius: 99px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    cursor: pointer;
}

.btn-primary {
    background: var(--primary);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(0, 122, 255, 0.3);
}

.btn-outline {
    border: 1px solid var(--surface-border);
    color: white;
    backdrop-filter: var(--glass);
}

.btn-outline:hover {
    background: var(--surface);
}

/* Features */
.section-title {
    text-align: center;
    margin-bottom: 4rem;
}

.section-title h2 {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.section-title p {
    color: var(--text-dim);
    font-size: 1.1rem;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.feature-card {
    background: var(--surface);
    border: 1px solid var(--surface-border);
    padding: 2.5rem;
    border-radius: 2rem;
    transition: all 0.3s;
}

.feature-card:hover {
    border-color: var(--primary);
    transform: translateY(-5px);
}

.feature-icon {
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
}

/* Product Section (Mixed media) */
.product-showcase {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 5rem;
    align-items: center;
}

.showcase-image {
    width: 100%;
    border-radius: 2rem;
    overflow: hidden;
}

/* Support/FAQ */
.support-tabs {
    background: var(--surface);
    border-radius: 2rem;
    padding: 3rem;
}

.faq-item {
    padding: 1.5rem 0;
    border-bottom: 1px solid var(--surface-border);
}

.faq-item:last-child {
    border-bottom: none;
}

.faq-q {
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.faq-a {
    color: var(--text-dim);
}

/* Contact Form */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

input, textarea {
    width: 100%;
    background: var(--surface);
    border: 1px solid var(--surface-border);
    padding: 1rem;
    border-radius: 0.75rem;
    color: white;
    outline: none;
}

input:focus, textarea:focus {
    border-color: var(--primary);
}

/* Footer */
footer {
    padding: 50px 0;
    border-top: 1px solid var(--surface-border);
    text-align: center;
    color: var(--text-dim);
}

/* Legal / Article Pages */
.legal-page {
    padding-top: 150px;
}

.article-content {
    background: var(--surface);
    border: 1px solid var(--surface-border);
    padding: 4rem;
    border-radius: 2rem;
    max-width: 900px;
    margin: 0 auto;
}

.article-content h1 {
    font-size: 2.5rem;
    margin-bottom: 2rem;
    text-align: center;
}

.article-content h2 {
    font-size: 1.5rem;
    margin: 2rem 0 1rem;
    color: var(--primary);
}

.article-content h3 {
    font-size: 1.2rem;
    margin: 1.5rem 0 0.8rem;
    color: var(--accent);
}

.article-content p {
    margin-bottom: 1.2rem;
    color: var(--text-dim);
    font-size: 1rem;
    line-height: 1.8;
}

.article-content ul {
    margin-bottom: 1.5rem;
    padding-left: 1.5rem;
    color: var(--text-dim);
}

.article-content li {
    margin-bottom: 0.5rem;
}

.back-home {
    display: inline-block;
    margin-bottom: 2rem;
    color: var(--text-dim);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

.back-home:hover {
    color: var(--primary);
}
[data-reveal] {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s ease-out;
}

[data-reveal].active {
    opacity: 1;
    transform: translateY(0);
}

@media (max-width: 768px) {
    /* Container / spacing */
    .container {
        padding: 0 1rem;
    }

    section {
        padding: 70px 0;
    }

    /* Navbar: drawer-style menu */
    nav {
        padding: 0.75rem 0;
    }

    .nav-content {
        align-items: center;
        position: relative;
        gap: 0.75rem;
    }

    .nav-links {
        display: none;
        position: absolute;
        left: 0;
        right: 0;
        top: 100%;
        margin-top: 0.5rem;
        padding: 0.75rem 1rem;
        background: rgba(3, 3, 3, 0.88);
        backdrop-filter: var(--glass);
        border-bottom: 1px solid var(--surface-border);
        flex-direction: column;
        gap: 0.75rem;
        z-index: 1001;
    }

    nav.nav-open .nav-links {
        display: flex;
    }

    .nav-toggle {
        display: inline-flex;
        align-items: center;
        justify-content: center;
    }

    .nav-links a {
        font-size: 1rem;
        width: 100%;
        text-align: center;
    }

    /* Hero: avoid 100vh issues on mobile, align to top */
    .hero {
        height: auto;
        min-height: unset;
        align-items: flex-start;
        padding: 6.5rem 0 3.5rem;
    }

    .hero-grid {
        grid-template-columns: 1fr;
        gap: 2.5rem;
    }

    .hero-content h1 {
        font-size: 2.6rem;
        margin-bottom: 1.25rem;
    }

    .hero-content p {
        font-size: 1.05rem;
        margin-bottom: 1.75rem;
    }

    /* Hero buttons: stack vertically; override inline margin */
    .hero-btns {
        display: flex;
        flex-direction: column;
        align-items: flex-start;
        gap: 0.9rem;
    }

    .hero-btns .btn {
        padding: 0.85rem 1.4rem;
    }

    .hero-btns .btn-outline {
        margin-left: 0 !important; /* override inline style in index.html */
    }

    /* Sections */
    .section-title {
        margin-bottom: 2.75rem;
    }

    .section-title h2 {
        font-size: 2.1rem;
        margin-bottom: 0.75rem;
    }

    .section-title p {
        font-size: 1rem;
    }

    /* Features */
    .feature-grid {
        grid-template-columns: 1fr;
        gap: 1.25rem;
    }

    .feature-card {
        padding: 1.5rem;
        border-radius: 1.5rem;
    }

    .feature-icon {
        font-size: 2rem;
        margin-bottom: 1rem;
    }

    /* Product / showcase */
    .product-showcase {
        grid-template-columns: 1fr;
        gap: 2.5rem;
    }

    /* Inline font-size in index.html: override on mobile */
    .product-showcase-section .showcase-content h2 {
        font-size: 2.1rem !important;
        margin-bottom: 1.25rem !important;
    }

    .product-showcase-section .showcase-content p {
        font-size: 1rem !important;
        margin-bottom: 1.5rem !important;
    }

    .family-care .showcase-content h2 {
        font-size: 2.1rem !important;
        margin-bottom: 1.25rem !important;
    }

    .family-care .showcase-content p {
        font-size: 1rem !important;
        margin-bottom: 1.5rem !important;
    }

    .family-care .product-showcase {
        /* index.html uses inline grid-template-columns which needs priority override */
        grid-template-columns: 1fr !important;
    }

    .showcase-image {
        border-radius: 1.5rem;
    }

    .product-showcase-section .showcase-image img,
    .family-care .showcase-image img {
        border-radius: 1.5rem !important; /* index.html has inline border-radius */
    }

    .support-tabs {
        padding: 1.75rem;
        border-radius: 1.5rem;
    }

    /* Contact form */
    .contact-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    input,
    textarea {
        padding: 0.9rem;
    }

    /* Footer */
    footer {
        padding: 35px 0;
    }

    /* Download block: override inline spacing/sizes */
    #download p[data-reveal] {
        margin-bottom: 2rem !important; /* index.html inline margin-bottom */
    }

    #download .download-btns {
        gap: 1.25rem !important; /* index.html inline gap */
    }

    #download .qr-code-wrapper img {
        width: 120px !important; /* index.html inline width */
        border-radius: 0.85rem !important; /* index.html inline border-radius */
    }

    #download .qr-code-wrapper p {
        font-size: 0.85rem !important; /* index.html inline font-size */
    }
}