/* Variables */
:root {
    --color-primary: #ffcc00;
    --color-primary-dark: #e6b800;
    --color-background: #F5F5F5;
    --color-text: #212121;
    --color-text-light: #757575;
    --color-white: #FFFFFF;
    --color-border: #E0E0E0;
    --color-success: #4CAF50;
    --color-warning: #FF9800;
    --color-error: #F44336;
    --spacing-unit: 16px;
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-background);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    margin-bottom: var(--spacing-unit);
    color: var(--color-text);
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
}

h2 {
    font-size: 2rem;
    margin-bottom: calc(var(--spacing-unit) * 1.5);
    text-align: center;
}

h3 {
    font-size: 1.5rem;
}

h4 {
    font-size: 1.1rem;
}

p {
    margin-bottom: var(--spacing-unit);
    color: var(--color-text-light);
    line-height: 1.7;
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: var(--transition);
}

a:hover {
    color: var(--color-primary-dark);
    text-decoration: underline;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-unit);
}

/* Header */
.header {
    background: var(--color-white);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-unit) var(--spacing-unit);
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-primary);
    letter-spacing: -0.5px;
}

.nav {
    display: flex;
    gap: calc(var(--spacing-unit) * 2);
}

.nav a {
    font-weight: 500;
    color: var(--color-text);
    transition: var(--transition);
}

.nav a:hover {
    color: var(--color-primary);
    text-decoration: none;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: var(--spacing-unit) calc(var(--spacing-unit) * 1.5);
    border-radius: 6px;
    font-weight: 600;
    text-align: center;
    cursor: pointer;
    border: none;
    transition: var(--transition);
    font-size: 1rem;
}

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

.btn-primary:hover {
    background-color: var(--color-primary-dark);
    text-decoration: none;
    box-shadow: 0 4px 12px rgba(255, 204, 0, 0.3);
}

.btn-large {
    padding: calc(var(--spacing-unit) * 1.2) calc(var(--spacing-unit) * 2.5);
    font-size: 1.1rem;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #ffffff 0%, #fffaed 100%);
    padding: calc(var(--spacing-unit) * 4) var(--spacing-unit);
    border-bottom: 1px solid var(--color-border);
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: calc(var(--spacing-unit) * 3);
    align-items: center;
}

.hero-content h1 {
    color: var(--color-text);
    margin-bottom: var(--spacing-unit);
}

.hero-subtitle {
    font-size: 1.3rem;
    color: var(--color-primary);
    font-weight: 600;
    margin-bottom: var(--spacing-unit);
}

.hero-description {
    font-size: 1.05rem;
    margin-bottom: calc(var(--spacing-unit) * 2);
    color: var(--color-text-light);
}

.hero-image {
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-image img {
    max-width: 100%;
    height: auto;
    width: 300px;
    border-radius: 12px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

/* APK Details Section */
.apk-details {
    background: var(--color-white);
    padding: calc(var(--spacing-unit) * 4) var(--spacing-unit);
}

.apk-details h2 {
    color: var(--color-text);
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.details-table {
    background: var(--color-background);
    border-radius: 8px;
    overflow: hidden;
    margin-bottom: calc(var(--spacing-unit) * 3);
}

.detail-row {
    display: grid;
    grid-template-columns: 200px 1fr;
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-unit);
    gap: var(--spacing-unit);
}

.detail-row:last-child {
    border-bottom: none;
}

.detail-label {
    font-weight: 600;
    color: var(--color-primary);
}

.detail-value {
    color: var(--color-text);
}

.download-box {
    background: linear-gradient(135deg, var(--color-primary) 0%, #ffcc00 100%);
    color: #333;
    padding: calc(var(--spacing-unit) * 2.5);
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 8px 20px rgba(255, 204, 0, 0.2);
}

.download-box h3 {
    color: #333;
    margin-bottom: var(--spacing-unit);
}

.download-box p {
    color: #555;
    margin-bottom: var(--spacing-unit);
}

.download-box .btn-primary {
    background-color: #333;
    color: var(--color-primary);
    margin: var(--spacing-unit) 0;
}

.download-box .btn-primary:hover {
    background-color: #555;
    color: var(--color-primary);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.25);
}

.file-info {
    font-size: 0.9rem;
    color: #666;
    margin-bottom: 0;
}

/* Features Section */
.features {
    background: var(--color-white);
    padding: calc(var(--spacing-unit) * 4) var(--spacing-unit);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: calc(var(--spacing-unit) * 2);
}

.feature-card {
    background: var(--color-background);
    padding: calc(var(--spacing-unit) * 2);
    border-radius: 12px;
    text-align: center;
    transition: var(--transition);
    border: 1px solid var(--color-border);
}

.feature-card:hover {
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
    transform: translateY(-4px);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-unit);
}

.feature-card h3 {
    color: var(--color-text);
    margin-bottom: var(--spacing-unit);
}

.feature-card p {
    color: var(--color-text-light);
    margin-bottom: 0;
}

/* Installation Section */
.installation {
    background: var(--color-background);
    padding: calc(var(--spacing-unit) * 4) var(--spacing-unit);
}

.installation-steps {
    background: var(--color-white);
    padding: calc(var(--spacing-unit) * 2);
    border-radius: 12px;
    margin-bottom: calc(var(--spacing-unit) * 3);
}

.installation-steps h3 {
    color: var(--color-text);
    margin-bottom: calc(var(--spacing-unit) * 2);
}

.steps {
    display: grid;
    gap: calc(var(--spacing-unit) * 2);
}

.step {
    display: grid;
    grid-template-columns: 60px 1fr;
    gap: calc(var(--spacing-unit) * 1.5);
}

.step-number {
    width: 60px;
    height: 60px;
    background: var(--color-primary);
    color: var(--color-white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.5rem;
    flex-shrink: 0;
}

.step-content h4 {
    color: var(--color-text);
    margin-bottom: 0.5rem;
}

.step-content p {
    color: var(--color-text-light);
    margin-bottom: 0;
    font-size: 0.95rem;
}

.installation-tips {
    background: #FFF8DC;
    padding: calc(var(--spacing-unit) * 2);
    border-radius: 12px;
    border-left: 4px solid var(--color-warning);
}

.installation-tips h3 {
    color: var(--color-text);
    margin-bottom: var(--spacing-unit);
}

.installation-tips ul {
    list-style: none;
    padding: 0;
}

.installation-tips li {
    padding: 0.5rem 0;
    color: var(--color-text-light);
}

.installation-tips li strong {
    color: var(--color-text);
}

/* Troubleshooting Section */
.troubleshooting {
    background: var(--color-white);
    padding: calc(var(--spacing-unit) * 4) var(--spacing-unit);
}

.troubleshooting-table {
    display: grid;
    gap: var(--spacing-unit);
}

.trouble-row {
    display: grid;
    grid-template-columns: 200px 1fr;
    gap: var(--spacing-unit);
    background: var(--color-background);
    padding: var(--spacing-unit);
    border-radius: 8px;
    border-left: 4px solid var(--color-warning);
}

.trouble-problem {
    font-weight: 600;
    color: var(--color-primary);
}

.trouble-fix {
    color: var(--color-text-light);
}

/* Content Guide Section */
.content-guide {
    background: var(--color-background);
    padding: calc(var(--spacing-unit) * 4) var(--spacing-unit);
}

.content-sections {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: calc(var(--spacing-unit) * 2);
}

.content-item {
    background: var(--color-white);
    padding: calc(var(--spacing-unit) * 2);
    border-radius: 12px;
    border: 1px solid var(--color-border);
}

.content-item h3 {
    color: var(--color-text);
    margin-bottom: var(--spacing-unit);
}

.content-item p {
    color: var(--color-text-light);
    margin-bottom: 0;
    font-size: 0.95rem;
}

/* Quality & Features Section */
.quality-features {
    background: var(--color-white);
    padding: calc(var(--spacing-unit) * 4) var(--spacing-unit);
}

.quality-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: calc(var(--spacing-unit) * 2);
}

.quality-card {
    background: var(--color-background);
    padding: calc(var(--spacing-unit) * 2);
    border-radius: 12px;
    border: 1px solid var(--color-border);
}

.quality-card h3 {
    color: var(--color-primary);
    margin-bottom: var(--spacing-unit);
}

.quality-card p {
    color: var(--color-text-light);
    margin-bottom: var(--spacing-unit);
}

.quality-card ul {
    list-style: none;
    padding: 0;
}

.quality-card li {
    padding: 0.5rem 0;
    color: var(--color-text);
    padding-left: 1.5rem;
    position: relative;
}

.quality-card li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--color-success);
    font-weight: bold;
}

/* Device Compatibility Section */
.device-compatibility {
    background: var(--color-background);
    padding: calc(var(--spacing-unit) * 4) var(--spacing-unit);
}

.compatibility-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: calc(var(--spacing-unit) * 2);
    margin-bottom: calc(var(--spacing-unit) * 3);
}

.compatibility-item {
    background: var(--color-white);
    padding: calc(var(--spacing-unit) * 2);
    border-radius: 12px;
    border-left: 4px solid var(--color-primary);
}

.compatibility-item h3 {
    color: var(--color-text);
    margin-bottom: var(--spacing-unit);
}

.compatibility-item p {
    color: var(--color-text-light);
    margin-bottom: 0;
}

.compatibility-note {
    background: #fffaed;
    padding: calc(var(--spacing-unit) * 2);
    border-radius: 8px;
    border-left: 4px solid var(--color-primary);
}

.compatibility-note p {
    color: var(--color-text);
    margin-bottom: 0;
}

/* FAQ Section */
.faq {
    background: var(--color-white);
    padding: calc(var(--spacing-unit) * 4) var(--spacing-unit);
}

.faq-list {
    display: grid;
    gap: var(--spacing-unit);
    max-width: 900px;
    margin: 0 auto;
}

.faq-item {
    background: var(--color-background);
    padding: calc(var(--spacing-unit) * 1.5);
    border-radius: 8px;
    border-left: 4px solid var(--color-primary);
    transition: var(--transition);
}

.faq-item:hover {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.faq-item h3 {
    color: var(--color-text);
    margin-bottom: var(--spacing-unit);
    cursor: pointer;
}

.faq-item p {
    color: var(--color-text-light);
    margin-bottom: 0;
}

/* Disclaimer Section */
.disclaimer {
    background: #F5F5F5;
    padding: calc(var(--spacing-unit) * 4) var(--spacing-unit);
    border-top: 1px solid var(--color-border);
}

.disclaimer h2 {
    color: var(--color-text);
}

.disclaimer p {
    color: var(--color-text-light);
    max-width: 900px;
    margin-left: auto;
    margin-right: auto;
}

/* Footer */
.footer {
    background: var(--color-text);
    color: var(--color-white);
    padding: calc(var(--spacing-unit) * 3) var(--spacing-unit);
    text-align: center;
    border-top: 1px solid var(--color-border);
}

.footer p {
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: 0.5rem;
}

.footer p:last-child {
    margin-bottom: 0;
}

/* Responsive Design */
@media (max-width: 768px) {
    h1 {
        font-size: 1.8rem;
    }

    h2 {
        font-size: 1.5rem;
    }

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

    .detail-row {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }

    .detail-label {
        font-weight: 600;
    }

    .nav {
        gap: var(--spacing-unit);
    }

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

    .step-number {
        width: 50px;
        height: 50px;
        font-size: 1.2rem;
    }

    .trouble-row {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }

    .header .container {
        flex-direction: column;
        gap: var(--spacing-unit);
    }
}

@media (max-width: 480px) {
    h1 {
        font-size: 1.5rem;
    }

    h2 {
        font-size: 1.2rem;
    }

    .container {
        padding: 0 var(--spacing-unit) * 0.5;
    }

    .hero {
        padding: calc(var(--spacing-unit) * 2) var(--spacing-unit);
    }

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

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

    .content-sections {
        grid-template-columns: 1fr;
    }

    .compatibility-grid {
        grid-template-columns: 1fr;
        margin-bottom: calc(var(--spacing-unit) * 2);
    }

    .btn-large {
        padding: var(--spacing-unit) calc(var(--spacing-unit) * 1.5);
        font-size: 1rem;
    }
}