:root {
    --bg-primary: #FFFFFF;
    --bg-secondary: #f5f5f5;
    --bg-tertiary: #eeeeee;
    --border: #e0e0e0;
    --yellow-primary: #F5C400;
    --yellow-hover: #FFD700;
    --orange-accent: #FF8C00;
    --text-primary: #1a1a1a;
    --text-muted: #555555;
    --text-dark: #999999;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
}

body {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    font-size: 16px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header / Navigation */
.header {
    position: sticky;
    top: 0;
    background-color: #FFFFFF;
    border-bottom: 1px solid var(--border);
    z-index: 1000;
    transition: box-shadow 0.3s ease;
}

.header.scrolled {
    box-shadow: var(--shadow-sm);
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo-section {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: var(--text-primary);
}

.logo {
    height: 40px;
    width: auto;
}

.brand-name {
    font-size: 20px;
    font-weight: bold;
    color: var(--text-primary);
}

.nav {
    display: flex;
    gap: 20px;
    align-items: center;
}

/* Buttons */
.cta-button {
    display: inline-block;
    background: linear-gradient(135deg, var(--yellow-primary) 0%, var(--orange-accent) 100%);
    color: #000000;
    padding: 12px 24px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: bold;
    font-size: 14px;
    border: none;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.cta-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(245, 196, 0, 0.3);
}

.cta-button.large {
    padding: 16px 40px;
    font-size: 18px;
    margin-top: 20px;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #FFFFFF 0%, rgba(245, 196, 0, 0.05) 100%);
    padding: 60px 0;
    border-bottom: 1px solid var(--border);
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    align-items: center;
}

.hero-content h1 {
    font-size: 48px;
    line-height: 1.2;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.hero-content .subtitle {
    font-size: 18px;
    color: var(--text-muted);
    margin-bottom: 30px;
    line-height: 1.5;
}

.stats {
    display: flex;
    gap: 30px;
    margin-bottom: 30px;
    flex-wrap: wrap;
}

.stat {
    padding: 12px 20px;
    background-color: var(--bg-secondary);
    border-radius: 6px;
    border-left: 3px solid var(--yellow-primary);
    font-weight: 600;
}

.hero-image {
    text-align: center;
}

.hero-image img {
    max-width: 100%;
    height: auto;
    filter: drop-shadow(0 0 30px rgba(245, 196, 0, 0.2));
}

/* APK Info Section */
.apk-info {
    padding: 60px 0;
    background-color: var(--bg-primary);
}

.apk-info h2 {
    font-size: 36px;
    margin-bottom: 40px;
    color: var(--text-primary);
}

.info-table {
    width: 100%;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 8px;
    overflow: hidden;
}

.info-table tr {
    border-bottom: 1px solid var(--border);
}

.info-table tr:last-child {
    border-bottom: none;
}

.info-table td {
    padding: 16px 20px;
}

.info-table .label {
    font-weight: 600;
    color: var(--yellow-primary);
    width: 40%;
    border-right: 1px solid var(--border);
}

.info-table .value {
    color: var(--text-muted);
}

/* Features Section */
.features {
    padding: 60px 0;
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.features h2 {
    font-size: 36px;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.section-intro {
    font-size: 16px;
    color: var(--text-muted);
    margin-bottom: 40px;
    max-width: 800px;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
}

.feature-card {
    background-color: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 30px 20px;
    text-align: center;
    transition: all 0.3s ease;
}

.feature-card:hover {
    border-top: 3px solid var(--yellow-primary);
    transform: translateY(-4px);
}

.feature-icon {
    font-size: 48px;
    margin-bottom: 15px;
    display: block;
}

.feature-card h3 {
    font-size: 18px;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.feature-card p {
    font-size: 14px;
    color: var(--text-muted);
    line-height: 1.5;
}

/* Installation Guide */
.install {
    padding: 60px 0;
    background-color: var(--bg-primary);
}

.install h2 {
    font-size: 36px;
    margin-bottom: 40px;
    color: var(--text-primary);
}

.steps {
    display: grid;
    gap: 30px;
    margin-bottom: 40px;
}

.step {
    display: grid;
    grid-template-columns: 60px 1fr;
    gap: 20px;
    align-items: flex-start;
}

.step-number {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--yellow-primary) 0%, var(--orange-accent) 100%);
    color: #000000;
    border-radius: 50%;
    font-weight: bold;
    font-size: 24px;
    flex-shrink: 0;
}

.step-content h3 {
    font-size: 18px;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.step-content p {
    font-size: 14px;
    color: var(--text-muted);
}

/* Devices Section */
.devices {
    padding: 60px 0;
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.devices h2 {
    font-size: 36px;
    margin-bottom: 40px;
    color: var(--text-primary);
}

.device-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.device-card {
    background-color: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 30px 20px;
    text-align: center;
}

.device-icon {
    font-size: 48px;
    margin-bottom: 15px;
    display: block;
}

.device-card h3 {
    font-size: 20px;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.device-card p {
    font-size: 14px;
    color: var(--text-muted);
    line-height: 1.5;
}

/* Troubleshoot Section */
.troubleshoot {
    padding: 60px 0;
    background-color: var(--bg-primary);
}

.troubleshoot h2 {
    font-size: 36px;
    margin-bottom: 40px;
    color: var(--text-primary);
}

.fix-table {
    width: 100%;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 8px;
    overflow: hidden;
}

.fix-table th {
    background-color: var(--bg-tertiary);
    padding: 16px 20px;
    text-align: left;
    font-weight: 600;
    color: var(--yellow-primary);
    border-bottom: 1px solid var(--border);
}

.fix-table tr {
    border-bottom: 1px solid var(--border);
}

.fix-table tr:last-child {
    border-bottom: none;
}

.fix-table td {
    padding: 16px 20px;
}

.fix-table td:first-child {
    font-weight: 600;
    color: var(--text-primary);
    width: 30%;
}

.fix-table td:last-child {
    color: var(--text-muted);
}

/* Content Grid Section */
.content-grid {
    padding: 60px 0;
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.content-grid h2 {
    font-size: 36px;
    margin-bottom: 40px;
    color: var(--text-primary);
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.grid-item {
    background-color: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 30px;
}

.grid-item h3 {
    font-size: 20px;
    margin-bottom: 15px;
    color: var(--yellow-primary);
}

.grid-item p {
    font-size: 14px;
    color: var(--text-muted);
    line-height: 1.6;
}

/* FAQ Section */
.faq {
    padding: 60px 0;
    background-color: var(--bg-primary);
}

.faq h2 {
    font-size: 36px;
    margin-bottom: 40px;
    color: var(--text-primary);
}

.faq-item {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 8px;
    margin-bottom: 15px;
    overflow: hidden;
}

.faq-item summary {
    padding: 20px;
    cursor: pointer;
    font-weight: 600;
    color: var(--text-primary);
    display: flex;
    justify-content: space-between;
    align-items: center;
    user-select: none;
    transition: background-color 0.2s ease;
}

.faq-item summary:hover {
    background-color: var(--bg-tertiary);
}

.faq-item[open] summary {
    border-bottom: 2px solid var(--yellow-primary);
    background-color: var(--bg-tertiary);
}

.faq-item p {
    padding: 0 20px 20px;
    color: var(--text-muted);
    font-size: 14px;
    line-height: 1.6;
}

.faq-item summary::after {
    content: '▼';
    font-size: 12px;
    color: var(--yellow-primary);
    transition: transform 0.3s ease;
}

.faq-item[open] summary::after {
    transform: rotate(180deg);
}

/* Disclaimer Section */
.disclaimer {
    padding: 60px 0;
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    text-align: center;
}

.disclaimer h2 {
    font-size: 28px;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.disclaimer p {
    font-size: 14px;
    color: var(--text-muted);
    max-width: 900px;
    margin: 0 auto;
    line-height: 1.6;
}

/* Footer */
.footer {
    background-color: #f5f5f5;
    border-top: 1px solid var(--border);
    padding: 40px 0;
}

.footer .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.footer p {
    font-size: 14px;
    color: var(--text-muted);
}

.footer-nav {
    display: flex;
    gap: 25px;
}

.footer-nav a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 14px;
    transition: color 0.2s ease;
}

.footer-nav a:hover {
    color: var(--yellow-primary);
}

/* Scroll to Top Button */
.scroll-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--yellow-primary) 0%, var(--orange-accent) 100%);
    color: #000000;
    border: none;
    border-radius: 50%;
    font-size: 24px;
    cursor: pointer;
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 999;
    transition: all 0.3s ease;
    box-shadow: var(--shadow);
}

.scroll-to-top.show {
    display: flex;
}

.scroll-to-top:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 28px rgba(245, 196, 0, 0.4);
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-container {
        grid-template-columns: 1fr;
        gap: 30px;
        padding: 0 20px;
    }

    .hero-content h1 {
        font-size: 32px;
    }

    .hero-content .subtitle {
        font-size: 16px;
    }

    .stats {
        gap: 15px;
    }

    .stat {
        padding: 10px 15px;
        font-size: 13px;
    }

    .info-table .label {
        width: 50%;
    }

    .info-table td {
        padding: 12px 15px;
        font-size: 13px;
    }

    .apk-info h2,
    .features h2,
    .install h2,
    .devices h2,
    .troubleshoot h2,
    .content-grid h2,
    .faq h2 {
        font-size: 28px;
    }

    .feature-grid {
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
        gap: 15px;
    }

    .feature-card {
        padding: 20px 15px;
    }

    .feature-icon {
        font-size: 36px;
    }

    .feature-card h3 {
        font-size: 16px;
    }

    .step {
        grid-template-columns: 50px 1fr;
        gap: 15px;
    }

    .step-number {
        width: 50px;
        height: 50px;
        font-size: 20px;
    }

    .step-content h3 {
        font-size: 16px;
    }

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

    .grid-3 {
        grid-template-columns: 1fr;
        gap: 20px;
    }

    .footer .container {
        flex-direction: column;
        text-align: center;
    }

    .footer-nav {
        flex-wrap: wrap;
        justify-content: center;
    }

    .scroll-to-top {
        width: 40px;
        height: 40px;
        font-size: 20px;
        bottom: 20px;
        right: 20px;
    }

    .header-container {
        height: 60px;
    }

    .nav {
        gap: 10px;
    }

    .cta-button {
        padding: 10px 16px;
        font-size: 12px;
    }
}

@media (max-width: 480px) {
    body {
        font-size: 14px;
    }

    .hero-content h1 {
        font-size: 24px;
    }

    .hero-content .subtitle {
        font-size: 14px;
    }

    .stats {
        flex-direction: column;
        gap: 10px;
    }

    .stat {
        width: 100%;
        text-align: center;
    }

    .info-table .label {
        width: 100%;
        border-right: none;
        border-bottom: 1px solid var(--border);
        margin-bottom: 5px;
    }

    .info-table .value {
        display: block;
        padding-top: 5px;
    }

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

    .feature-card {
        padding: 20px;
    }

    .faq-item summary {
        padding: 15px;
        font-size: 14px;
    }

    .faq-item p {
        padding: 0 15px 15px;
        font-size: 12px;
    }

    .disclaimer h2 {
        font-size: 22px;
    }

    .disclaimer p {
        font-size: 12px;
    }
}