/* --- Global Settings & Variables --- */
:root {
    --primary-color: #007bff;
    --dark-blue: #0a2540;
    --light-gray: #f7f7f7;
    --text-color: #333;
    --white: #fff;
    --lg-red: #DE0029;
    --samsung-blue: #0033A0;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
}

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

h1, h2, h3 {
    line-height: 1.2;
}

img {
    max-width: 100%;
}

/* --- Mobile First Styles (Default) --- */

/* General Header */
header {
    background: var(--white);
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    padding: 1rem 0;
}
header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
}
.logo {
    font-size: 1.4rem;
    font-weight: bold;
    color: var(--dark-blue);
}
nav {
    width: 100%;
    margin-top: 10px;
}
nav ul {
    list-style: none;
    display: flex;
    justify-content: space-around;
}
nav ul li a {
    color: var(--text-color);
    font-weight: 500;
    text-decoration: none;
    padding: 5px;
}

/* Brand-Specific Header */
.brand-header .brand-logo img {
    height: 30px;
}
.brand-header .header-call a {
    font-weight: bold;
    color: var(--primary-color);
    text-decoration: none;
    font-size: 1rem;
}

/* Hero Section */
.hero {
    background-color: var(--dark-blue);
    color: var(--white);
    text-align: center;
    padding: 60px 20px;
}
.hero-lg { background-color: var(--lg-red); }
.hero-samsung { background-color: var(--samsung-blue); }
.hero-vu { background-color: var(--dark-blue); }

.hero h1 {
    font-size: 2.2rem;
    margin-bottom: 15px;
}
.hero p {
    font-size: 1.1rem;
    margin-bottom: 30px;
}
.cta-button {
    background: var(--primary-color);
    color: var(--white);
    padding: 15px 25px;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: bold;
    text-decoration: none;
    display: inline-block;
}
.hero-lg .cta-button { background: var(--white); color: var(--lg-red); }
.hero-samsung .cta-button { background: var(--white); color: var(--samsung-blue); }

/* General Sections */
section {
    padding: 50px 0;
}
section h2 {
    text-align: center;
    font-size: 2rem;
    margin-bottom: 30px;
}

/* Brands Section */
.brands { background-color: var(--light-gray); }
.brand-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
}
.brand-card {
    background: var(--white);
    padding: 25px;
    border-radius: 8px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.05);
    text-align: center;
    text-decoration: none;
    color: var(--text-color);
}
.brand-card img { height: 35px; margin-bottom: 15px; }
.brand-card h3 { margin-bottom: 10px; }
.brand-card span { font-weight: bold; color: var(--primary-color); margin-top: 15px; display: inline-block; }

/* Features Grid */
.features-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 30px;
    text-align: center;
}

/* Page Content (For Brand Pages) */
.page-content { padding-top: 30px; }
.page-content h2 { text-align: left; }
.issues-list, .models-list {
    list-style: '✓  ';
    padding-left: 20px;
    margin-bottom: 30px;
}
.issues-list li, .models-list li {
    margin-bottom: 10px;
    font-size: 1.1rem;
}
.highlight {
    background: var(--light-gray);
    border-left: 5px solid var(--primary-color);
    padding: 20px;
    font-size: 1.1rem;
    font-style: italic;
    margin: 30px 0;
    text-align: center;
}

/* Footer */
footer {
    background: var(--dark-blue);
    color: #ccc;
    padding: 30px 0;
    text-align: center;
}
.disclaimer {
    font-size: 0.8rem;
    max-width: 600px;
    margin: 0 auto;
}

/* Floating Call Button */
.floating-call-button {
    position: fixed;
    width: 60px;
    height: 60px;
    bottom: 20px;
    right: 20px;
    background-color: #25D366; /* WhatsApp Green */
    color: #FFF;
    border-radius: 50px;
    text-align: center;
    font-size: 30px;
    box-shadow: 2px 2px 6px rgba(0,0,0,0.3);
    z-index: 1000;
    line-height: 60px;
    text-decoration: none;
}

/* --- Tablet & Desktop Styles --- */
@media (min-width: 768px) {
    /* Header */
    nav {
        width: auto;
        margin-top: 0;
    }
    nav ul li {
        margin-left: 25px;
    }

    /* Brand Header */
    .brand-header .brand-logo img {
        height: 40px;
    }
    .brand-header .header-call a {
        font-size: 1.1rem;
    }

    /* Hero */
    .hero { padding: 80px 20px; }
    .hero h1 { font-size: 2.8rem; }
    .hero p { font-size: 1.2rem; }

    /* Grids */
    .brand-grid {
        grid-template-columns: repeat(3, 1fr);
    }
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    /* Brand Page Lists */
    .issues-list, .models-list {
        columns: 2;
    }
}

@media (min-width: 1024px) {
    .features-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}