:root {
    --primary-color: #FF00CC;
    --secondary-color: #FF7F32;
    --tertiary-color: #D7413D;
    --text-color: #333;
    --bg-color: #fff;
    --font-family: 'Open Sans', sans-serif;
}

body {
    font-family: var(--font-family);
    color: var(--text-color);
    margin: 0;
    line-height: 1.6;
    font-size: 16px; 
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

header {
    padding: 20px 0;
    border-bottom: 1px solid #eee;
    text-align: center; 
}

.logo {
    height: 35px;
}

/* Banner Section */
.banner img {
    width: 100%;
    display: block;
}

/* Intro Section */
.intro {
    padding: 60px 0;
    text-align: center;
}

.intro h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.intro h2 {
    font-size: 1.2em;
    font-weight: 400;
    margin-bottom: 20px;
}

.intro p {
    font-size: 1em;
    margin-bottom: 30px;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.cta-button, .cta-button-secondary {
    display: inline-block;
    padding: 15px 30px;
    text-decoration: none;
    font-weight: 700;
    border-radius: 5px;
    transition: all 0.3s ease;
}

.cta-button {
    background: var(--secondary-color);
    color: white;
}

.cta-button:hover {
    background: var(--tertiary-color);
}

/* Promotion Section */
.promotion {
    padding: 60px 0;
    text-align: center;
    background: #f9f9f9;
}

.promotion h2 {
    color: var(--tertiary-color);
    font-size: 2em;
    margin-bottom: 20px;
}

.cta-button-secondary {
    background: var(--primary-color);
    color: white;
}

.cta-button-secondary:hover {
    background: var(--tertiary-color);
}

/* Features Section */
.features {
    padding: 60px 0;
}

.features h2 {
    text-align: center;
    font-size: 2em;
    margin-bottom: 40px;
}

.feature-grid {
    display: grid;
    grid-template-columns: 1fr; 
    gap: 30px;
}

.feature {
    background: #f9f9f9;
    padding: 30px;
    border-radius: 5px;
    border-left: 5px solid var(--secondary-color);
}

.feature h3 {
    color: var(--primary-color);
    margin-bottom: 15px;
}

/* Device List Section */
.device-list {
    padding: 60px 0;
    background: #f9f9f9;
}

.device-list h2 {
    text-align: center;
    font-size: 2em;
    margin-bottom: 20px;
}

.device-list p {
    text-align: center;
    margin-bottom: 30px;
}

#phoneSearch {
    width: 100%;
    padding: 15px;
    font-size: 1em;
    border: 1px solid #ccc;
    border-radius: 5px;
    margin-bottom: 20px;
    box-sizing: border-box;
}

#phoneList {
    list-style: none;
    padding: 0;
    columns: 1; 
}

#phoneList li {
    padding: 10px;
    border-bottom: 1px solid #eee;
}

/* FAQ Section */
.faq {
    padding: 60px 0;
}

.faq h2 {
    text-align: center;
    font-size: 2em;
    margin-bottom: 40px;
}

.sim-notice {
    background-color: #fff5f5; /* Light red background */
    border: 1px solid var(--tertiary-color);
    border-radius: 5px;
    padding: 20px;
    margin-bottom: 40px;
}

.sim-notice h3 {
    color: var(--tertiary-color);
    margin-top: 0;
}

.faq details {
    border-bottom: 1px solid #eee;
    padding: 15px 0;
}

.faq details:last-of-type {
    border-bottom: none;
}

.faq summary {
    font-weight: 600;
    cursor: pointer;
    list-style: none; /* Remove default marker */
    padding-right: 25px;
    position: relative;
}

.faq summary::-webkit-details-marker {
    display: none; /* Hide for Chrome/Safari */
}

.faq summary::after { /* Custom dropdown arrow */
    content: '+';
    position: absolute;
    right: 5px;
    top: 0;
    font-size: 1.5em;
    color: var(--primary-color);
    transition: transform 0.2s;
}

.faq details[open] summary::after {
    transform: rotate(45deg);
}

.faq details p {
    margin-top: 15px;
    padding-left: 10px;
}


/* Footer */
footer {
    background: var(--text-color);
    color: white;
    text-align: center;
    padding: 20px 0;
}

/* ---------------------------------- */
/* MEDIA QUERIES FOR DESKTOP     */
/* ---------------------------------- */
@media (min-width: 768px) {

    body {
        font-size: 18px; 
    }

    header {
        text-align: left; 
    }
    
    .logo {
        height: 40px;
    }
    
    .intro {
        padding: 80px 0;
    }
    
    .intro h1 {
        font-size: 3.5em;
    }
    
    .intro h2 {
        font-size: 1.5em;
    }

    .promotion, .features, .device-list, .faq {
        padding: 80px 0;
    }

    .promotion h2, .features h2, .device-list h2, .faq h2 {
        font-size: 2.5em;
    }

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

    #phoneList {
        columns: 3; 
        -webkit-columns: 3;
        -moz-columns: 3;
    }
}