/* Global Styles */
:root {
    --main-color: #0052CC; /* OKX Blue */
    --accent-color: #FFD700; /* Gold/Yellow for CTA */
    --light-bg: #f8f9fa;
    --dark-bg: #121a2f;
    --text-color: #333;
    --light-text: #fff;
    --border-radius: 8px;
    --box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

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

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--light-bg);
}

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

section {
    padding: 60px 0;
}

h1, h2, h3 {
    margin-bottom: 20px;
    font-weight: 700;
}

h2 {
    text-align: center;
    font-size: 2rem;
    position: relative;
    padding-bottom: 15px;
}

h2:after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background-color: var(--accent-color);
}

/* Hero Banner */
.hero-banner {
    background: linear-gradient(to right, var(--dark-bg), var(--main-color));
    color: var(--light-text);
    padding: 80px 0;
    text-align: center;
}

.hero-banner h1 {
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.referral-code {
    font-size: 1.3rem;
    margin-bottom: 25px;
}

.code {
    font-weight: 700;
    background-color: rgba(255, 255, 255, 0.2);
    padding: 4px 10px;
    border-radius: var(--border-radius);
    margin: 0 5px;
}

.cta-button {
    background-color: var(--accent-color);
    color: var(--dark-bg);
    padding: 12px 30px;
    font-size: 1.1rem;
    font-weight: 600;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: all 0.3s ease;
}

.cta-button:hover {
    background-color: #FFCC00;
    transform: translateY(-3px);
    box-shadow: 0 6px 15px rgba(0, 0, 0, 0.2);
}

/* What Is OKX Section */
.what-is-okx {
    background-color: #fff;
}

.info-container {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.info-container p {
    font-size: 1.2rem;
    margin-bottom: 30px;
}

.features {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 20px;
}

.feature-item {
    background-color: var(--light-bg);
    padding: 20px;
    border-radius: var(--border-radius);
    width: 200px;
    display: flex;
    flex-direction: column;
    align-items: center;
    box-shadow: var(--box-shadow);
}

.feature-item i {
    font-size: 2rem;
    color: var(--main-color);
    margin-bottom: 15px;
}

/* Why Use Our Referral Section */
.why-referral {
    background-color: var(--light-bg);
}

.benefits {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 30px;
    margin-top: 40px;
}

.benefit-card {
    background-color: #fff;
    padding: 30px;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    flex: 1;
    min-width: 250px;
    max-width: 350px;
    text-align: center;
    transition: transform 0.3s ease;
}

.benefit-card:hover {
    transform: translateY(-10px);
}

.benefit-icon {
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.benefit-card h3 {
    font-size: 1.3rem;
    margin-bottom: 15px;
}

/* Registration Guide */
.registration-guide {
    background-color: #fff;
}

.steps {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 30px;
    margin-top: 40px;
}

.step {
    text-align: center;
    flex: 1;
    min-width: 200px;
    max-width: 250px;
    position: relative;
}

.step-number {
    background-color: var(--main-color);
    color: var(--light-text);
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    margin: 0 auto 15px;
}

.step-icon {
    font-size: 2rem;
    color: var(--main-color);
    margin-bottom: 15px;
}

.step:not(:last-child):after {
    content: '→';
    position: absolute;
    right: -20px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 1.5rem;
    color: var(--main-color);
    display: none;
}

@media (min-width: 768px) {
    .step:not(:last-child):after {
        display: block;
    }
}

/* Fees Comparison */
.fees-comparison {
    background-color: var(--light-bg);
}

.table-container {
    overflow-x: auto;
    margin-top: 40px;
}

.fees-table {
    width: 100%;
    border-collapse: collapse;
    box-shadow: var(--box-shadow);
    background-color: #fff;
    border-radius: var(--border-radius);
    overflow: hidden;
}

.fees-table th, .fees-table td {
    padding: 15px;
    text-align: center;
    border-bottom: 1px solid #eee;
}

.fees-table th {
    background-color: var(--main-color);
    color: var(--light-text);
    font-weight: 600;
}

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

.discount {
    color: #28a745;
    font-weight: 600;
}

/* Latest Tutorials Section */
.latest-tutorials {
    background-color: #fff;
    padding: 70px 0;
}

.tutorials-container {
    margin-top: 40px;
    display: flex;
    flex-direction: column;
    gap: 25px;
}

.tutorial-item {
    display: flex;
    background-color: var(--light-bg);
    border-radius: var(--border-radius);
    padding: 25px;
    box-shadow: var(--box-shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.tutorial-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
}

.tutorial-icon {
    font-size: 2rem;
    color: var(--main-color);
    margin-right: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 60px;
}

.tutorial-content {
    flex: 1;
}

.tutorial-content h3 {
    margin-bottom: 8px;
    color: var(--main-color);
    font-size: 1.3rem;
}

.tutorial-date {
    color: #666;
    font-size: 0.9rem;
    margin-bottom: 12px;
}

.tutorial-description {
    margin-bottom: 15px;
    line-height: 1.5;
}

.tutorial-tags {
    display: flex;
    gap: 10px;
}

.tag {
    background-color: rgba(0, 82, 204, 0.1);
    color: var(--main-color);
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
}

.tutorials-note {
    margin-top: 30px;
    background-color: rgba(255, 215, 0, 0.1);
    border-left: 4px solid var(--accent-color);
    padding: 15px 20px;
    border-radius: 0 var(--border-radius) var(--border-radius) 0;
}

.tutorials-note p {
    display: flex;
    align-items: center;
    gap: 10px;
}

.tutorials-note i {
    color: var(--accent-color);
    font-size: 1.2rem;
}

@media (max-width: 768px) {
    .tutorial-item {
        flex-direction: column;
    }
    
    .tutorial-icon {
        margin-right: 0;
        margin-bottom: 15px;
    }
}

/* FAQs */
.faqs {
    background-color: #fff;
}

.faq-container {
    max-width: 800px;
    margin: 30px auto 0;
}

.faq-item {
    margin-bottom: 15px;
    border: 1px solid #eee;
    border-radius: var(--border-radius);
    overflow: hidden;
}

.faq-question {
    padding: 20px;
    background-color: var(--light-bg);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.faq-question h3 {
    margin: 0;
    font-size: 1.1rem;
}

.toggle-icon {
    font-size: 1.3rem;
    font-weight: 700;
}

.faq-answer {
    padding: 0 20px;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
}

.faq-item.active .faq-answer {
    padding: 20px;
    max-height: 1000px;
}

.faq-item.active .toggle-icon {
    transform: rotate(45deg);
}

/* Trust Section */
.trust-signals {
    background-color: var(--light-bg);
}

.trust-items {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 30px;
    margin-top: 40px;
}

.trust-item {
    text-align: center;
    flex: 1;
    min-width: 200px;
    max-width: 250px;
}

.trust-icon {
    font-size: 2rem;
    color: var(--main-color);
    margin-bottom: 15px;
}

/* YouTube Video Section */
.youtube-video {
    background-color: #fff;
    padding: 70px 0;
}

.video-container {
    position: relative;
    padding-bottom: 56.25%; /* 16:9 Aspect Ratio */
    height: 0;
    overflow: hidden;
    max-width: 900px;
    margin: 0 auto;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border-radius: var(--border-radius);
}

.video-description {
    text-align: center;
    max-width: 800px;
    margin: 25px auto 0;
    font-size: 1.1rem;
    color: var(--text-color);
}

/* Sticky Footer */
.sticky-footer {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    background-color: var(--dark-bg);
    color: var(--light-text);
    padding: 15px 0;
    box-shadow: 0 -4px 10px rgba(0, 0, 0, 0.1);
    z-index: 100;
}

.sticky-footer .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 15px;
}

.copy-btn {
    background-color: var(--light-bg);
    color: var(--dark-bg);
    padding: 8px 15px;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s ease;
}

.copy-btn:hover {
    background-color: #e2e6ea;
}

/* Responsive Design */
@media (max-width: 768px) {
    section {
        padding: 40px 0;
    }
    
    .hero-banner {
        padding: 60px 0;
    }
    
    .hero-banner h1 {
        font-size: 2rem;
    }
    
    .benefits, .steps, .trust-items {
        flex-direction: column;
        align-items: center;
    }
    
    .sticky-footer .container {
        justify-content: center;
        text-align: center;
    }
    
    .sticky-footer p, .sticky-footer button {
        width: 100%;
        margin-bottom: 10px;
    }
    
    /* Additional mobile optimization */
    .feature-item {
        width: 150px;
        padding: 15px;
    }
    
    .benefit-card, .step {
        min-width: 100%;
        max-width: 100%;
        margin-bottom: 20px;
    }
    
    .step:not(:last-child):after {
        display: none;
    }
    
    /* Stacked steps for mobile */
    .steps {
        position: relative;
    }
    
    .steps:before {
        content: '';
        position: absolute;
        left: 50%;
        top: 0;
        bottom: 0;
        width: 2px;
        background-color: var(--main-color);
        transform: translateX(-50%);
        z-index: 0;
    }
    
    .step {
        position: relative;
        z-index: 1;
        background-color: #fff;
        padding: 15px;
        border-radius: var(--border-radius);
        box-shadow: var(--box-shadow);
    }
    
    /* Table responsiveness */
    .fees-table th, .fees-table td {
        padding: 10px;
    }
    
    /* Video container for mobile */
    .video-container {
        margin: 0 10px;
    }
}

@media (max-width: 480px) {
    .hero-banner h1 {
        font-size: 1.8rem;
    }
    
    .referral-code {
        font-size: 1.1rem;
    }
    
    h2 {
        font-size: 1.7rem;
    }
    
    /* Additional small mobile optimization */
    .container {
        padding: 0 15px;
    }
    
    .features {
        gap: 10px;
    }
    
    .feature-item {
        width: 130px;
        font-size: 0.9rem;
    }
    
    .feature-item i {
        font-size: 1.6rem;
    }
    
    .benefit-icon, .trust-icon, .step-icon {
        font-size: 2rem;
    }
    
    .benefit-card h3, .faq-question h3 {
        font-size: 1.1rem;
    }
    
    .benefit-card {
        padding: 20px;
    }
    
    .fees-table {
        font-size: 0.9rem;
    }
    
    .fees-table th, .fees-table td {
        padding: 8px 5px;
    }
    
    /* Adjust spacing for stacked elements */
    .steps, .benefits, .trust-items {
        gap: 15px;
    }
    
    /* Fix sticky footer for very small screens */
    .sticky-footer {
        padding: 10px 0;
    }
    
    .sticky-footer .container {
        gap: 8px;
    }
    
    .cta-button, .copy-btn {
        font-size: 0.95rem;
        padding: 10px 20px;
    }
}

/* Fix orientation change issues */
@media screen and (orientation: landscape) and (max-height: 500px) {
    .hero-banner {
        padding: 30px 0;
    }
    
    .hero-banner h1 {
        font-size: 1.6rem;
        margin-bottom: 10px;
    }
    
    .referral-code {
        margin-bottom: 15px;
    }
    
    /* Handle sticky footer in landscape on small devices */
    .sticky-footer {
        position: static;
        margin-top: 30px;
    }
    
    body {
        padding-bottom: 0 !important;
    }
}

/* High-DPI screens (Retina) */
@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
    body {
        -webkit-font-smoothing: antialiased;
        -moz-osx-font-smoothing: grayscale;
    }
}

/* Mobile-specific styles */
.mobile-device {
    -webkit-tap-highlight-color: transparent; /* Remove tap highlight */
}

.mobile-device button {
    transition: transform 0.2s, opacity 0.2s;
}

.mobile-device .benefit-card {
    padding: 20px 15px;
}

.static-footer {
    position: static !important;
    box-shadow: none;
    margin-top: 30px;
}

/* Responsive touch targets for mobile */
@media (max-width: 768px) {
    button, 
    .faq-question,
    .benefit-card,
    .feature-item {
        cursor: pointer;
        -webkit-tap-highlight-color: transparent;
        touch-action: manipulation;
    }
    
    /* Add padding to ensure sufficient touch target size */
    .faq-question {
        padding: 20px 15px;
    }
    
    .toggle-icon {
        padding: 10px;
        margin: -10px;
    }
    
    /* Fix focus issues on mobile */
    button:focus,
    a:focus {
        outline: none;
    }
}