/* === MASTER CSS - mcdhot.com === */
:root {
    --primary: #0066ff;
    --primary-dark: #0044cc;
    --accent: #00cc66;
    --bg: #0a0a1a;
    --card-bg: #12122a;
    --text: #e0e0ff;
    --text-muted: #8888bb;
    --border: #1a1a3e;
    --gradient: linear-gradient(135deg, #0066ff, #00cc66);
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.7;
    overflow-x: hidden;
}
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* === Header === */
header {
    background: rgba(13,13,58,0.8);
    border-bottom: 1px solid var(--border);
    padding: 1rem 2rem;
    position: sticky; top: 0; z-index: 100;
    backdrop-filter: blur(10px);
}
header nav {
    max-width: 1200px; margin: 0 auto;
    display: flex; justify-content: space-between; align-items: center;
}
header .logo {
    font-size: 1.3rem; font-weight: 800;
    background: var(--gradient);
    -webkit-background-clip: text; -webkit-text-fill-color: transparent;
    background-clip: text;
}
header .nav-links { display: flex; gap: 1.5rem; list-style: none; }
header .nav-links a { color: var(--text); font-weight: 500; font-size: 0.95rem; }
header .nav-links a:hover { color: var(--primary); text-decoration: none; }

/* === Container === */
.container { max-width: 1200px; margin: 0 auto; padding: 2rem; }
.container-narrow { max-width: 860px; margin: 0 auto; padding: 2rem; }
.breadcrumb { margin-bottom: 1.5rem; color: var(--text-muted); font-size: 0.9rem; }
.breadcrumb a { color: var(--text-muted); }
.breadcrumb a:hover { color: var(--primary); }

/* === Hero === */
.hero {
    min-height: 100vh;
    display: flex; flex-direction: column; align-items: center; justify-content: center;
    text-align: center; padding: 2rem;
    position: relative;
    background: radial-gradient(ellipse at center, #0d0d3a 0%, var(--bg) 70%);
}
.hero::before {
    content: ''; position: absolute; top: 0; left: 0; right: 0; bottom: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' xmlns='http://www.w3.org/2000/svg'%3E%3Cdefs%3E%3Cpattern id='grid' width='60' height='60' patternUnits='userSpaceOnUse'%3E%3Cpath d='M 60 0 L 0 0 0 60' fill='none' stroke='%231a1a3e' stroke-width='0.5'/%3E%3C/pattern%3E%3C/defs%3E%3Crect width='100%25' height='100%25' fill='url(%23grid)'/%3E%3C/svg%3E");
    opacity: 0.5; pointer-events: none;
}
.hero-content { position: relative; z-index: 1; max-width: 900px; }
.hero-badge {
    display: inline-block; background: rgba(0,102,255,0.15); color: var(--primary);
    padding: 0.5rem 1.5rem; border-radius: 50px; font-weight: 600; font-size: 0.9rem;
    margin-bottom: 2rem; border: 1px solid rgba(0,102,255,0.3);
    animation: fadeInDown 0.8s ease;
}
.hero h1 {
    font-size: clamp(2rem, 5vw, 3.5rem); font-weight: 800;
    background: var(--gradient);
    -webkit-background-clip: text; -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 1.5rem; line-height: 1.2;
    animation: fadeInUp 0.8s ease;
}
.hero-subtitle { font-size: clamp(1rem, 2.5vw, 1.3rem); color: var(--text-muted); margin-bottom: 2.5rem; animation: fadeInUp 1s ease; }
.price-tag { font-size: 3rem; font-weight: 900; color: var(--accent); margin: 1.5rem 0; animation: pulse 2s infinite, fadeInUp 1.2s ease; }
.price-tag small { font-size: 1rem; color: var(--text-muted); }

/* === Sections === */
.section { max-width: 1200px; margin: 0 auto; padding: 4rem 2rem; }
.section-title {
    text-align: center; font-size: 2.2rem; font-weight: 800; margin-bottom: 1rem;
    background: var(--gradient);
    -webkit-background-clip: text; -webkit-text-fill-color: transparent;
    background-clip: text;
}
.section-desc { text-align: center; color: var(--text-muted); font-size: 1.1rem; margin-bottom: 3rem; }

/* === Features Grid === */
.features-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 1.5rem; }
.feature-card {
    background: var(--card-bg); border: 1px solid var(--border); border-radius: 16px;
    padding: 2rem; transition: all 0.3s ease; text-align: center;
}
.feature-card:hover { transform: translateY(-5px); border-color: var(--primary); box-shadow: 0 10px 40px rgba(0,102,255,0.15); }
.feature-card h3 { color: var(--primary); margin-bottom: 0.8rem; font-size: 1.2rem; }
.feature-card p { color: var(--text-muted); font-size: 0.95rem; }
svg.icon { width: 40px; height: 40px; display: block; margin: 0 auto 1rem; }

/* === Pricing === */
.specs-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 1.5rem; margin-top: 2rem; }
.spec-card { background: var(--card-bg); border: 1px solid var(--border); border-radius: 16px; padding: 2rem; position: relative; overflow: hidden; }
.spec-card.featured { border-color: var(--primary); box-shadow: 0 0 30px rgba(0,102,255,0.2); }
.spec-card.featured::before {
    content: 'PHỔ BIẾN NHẤT'; position: absolute; top: 1rem; right: -2rem;
    background: var(--gradient); color: white; padding: 0.3rem 3rem;
    transform: rotate(45deg); font-size: 0.7rem; font-weight: 700;
}
.spec-card h3 { font-size: 1.4rem; margin-bottom: 1rem; color: white; }
.spec-price { font-size: 2.5rem; font-weight: 900; color: var(--accent); }
.spec-price small { font-size: 0.9rem; color: var(--text-muted); font-weight: 400; }
.spec-details { margin: 1.5rem 0; list-style: none; }
.spec-details li { padding: 0.5rem 0; border-bottom: 1px solid var(--border); color: var(--text-muted); font-size: 0.95rem; display: flex; align-items: center; gap: 0.5rem; }
.spec-details li svg { min-width: 16px; }
.spec-cta { display: block; text-align: center; background: var(--gradient); color: white; padding: 0.8rem; border-radius: 10px; text-decoration: none; font-weight: 700; margin-top: 1rem; transition: all 0.3s ease; }
.spec-cta:hover { transform: translateY(-2px); box-shadow: 0 5px 20px rgba(0,102,255,0.4); }

/* === Countries === */
.countries-grid { display: flex; flex-wrap: wrap; gap: 1rem; justify-content: center; margin-top: 2rem; }
.country-tag { background: var(--card-bg); border: 1px solid var(--border); padding: 0.8rem 1.5rem; border-radius: 50px; font-weight: 600; color: var(--text); transition: all 0.3s ease; cursor: default; display: flex; align-items: center; gap: 0.5rem; }
.country-tag:hover { border-color: var(--primary); background: rgba(0,102,255,0.1); transform: scale(1.05); }
.country-flag { width: 22px; height: 16px; border-radius: 2px; }

/* === Promo === */
.promo-badge { display: inline-block; background: rgba(0,204,102,0.1); border: 1px dashed var(--accent); color: var(--accent); padding: 0.6rem 1.5rem; border-radius: 8px; font-size: 1rem; margin: 1rem 0; animation: fadeInUp 1.6s ease; }
.promo-badge strong { letter-spacing: 2px; font-size: 1.1rem; }
.promo-banner { max-width: 700px; margin: 2rem auto; padding: 1rem 2rem; background: rgba(0,204,102,0.1); border: 1px dashed var(--accent); border-radius: 12px; text-align: center; color: var(--text); font-size: 0.95rem; display: flex; align-items: center; justify-content: center; gap: 0.5rem; flex-wrap: wrap; }
.promo-banner strong { letter-spacing: 2px; color: var(--accent); }
.promo-banner svg { min-width: 20px; }

/* === CTA === */
.cta-button { display: inline-block; background: var(--gradient); color: white; font-size: 1.2rem; font-weight: 700; padding: 1rem 3rem; border-radius: 50px; text-decoration: none; transition: all 0.3s ease; box-shadow: 0 0 30px rgba(0,102,255,0.4); letter-spacing: 0.5px; }
.cta-button:hover { transform: translateY(-3px); box-shadow: 0 0 50px rgba(0,102,255,0.6); }
.cta-section { text-align: center; padding: 6rem 2rem; background: radial-gradient(ellipse at center, #0d0d3a 0%, var(--bg) 70%); }
.cta-section h2 { font-size: 2rem; font-weight: 800; margin-bottom: 1rem; }
.cta-section p { color: var(--text-muted); margin-bottom: 2rem; font-size: 1.1rem; }
.cta-box { margin: 3rem 0; text-align: center; padding: 2rem; background: rgba(0,204,102,0.06); border: 1px dashed var(--accent); border-radius: 16px; }
.cta-box .cta-button { display: inline-block; background: var(--gradient); color: #fff; font-size: 1.1rem; font-weight: 700; padding: 0.9rem 2.5rem; border-radius: 50px; text-decoration: none; margin-top: 1rem; transition: all .3s ease; box-shadow: 0 0 30px rgba(0,102,255,0.3); }
.cta-box .cta-button:hover { transform: translateY(-3px); box-shadow: 0 0 50px rgba(0,102,255,0.5); }

/* === Blog === */
.articles-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(350px, 1fr)); gap: 1.5rem; }
.article-card { background: var(--card-bg); border: 1px solid var(--border); border-radius: 16px; padding: 1.8rem; transition: all .3s ease; }
.article-card:hover { transform: translateY(-3px); border-color: var(--primary); box-shadow: 0 10px 40px rgba(0,102,255,0.12); }
.article-card .category { display: inline-block; background: rgba(0,204,102,0.12); color: var(--accent); padding: 0.2rem 0.8rem; border-radius: 50px; font-size: 0.8rem; font-weight: 600; margin-bottom: 0.8rem; }
.article-card h2 { font-size: 1.25rem; margin-bottom: 0.8rem; line-height: 1.4; }
.article-card h2 a { color: var(--text); }
.article-card h2 a:hover { color: var(--primary); text-decoration: none; }
.article-card p { color: var(--text-muted); font-size: 0.95rem; margin-bottom: 1rem; }
.article-card .meta { font-size: 0.85rem; color: var(--text-muted); display: flex; gap: 1rem; }

/* === Article detail === */
article h1 { font-size: 2.2rem; font-weight: 800; margin-bottom: 0.5rem; background: var(--gradient); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; line-height: 1.3; }
article .meta { color: var(--text-muted); font-size: 0.9rem; margin-bottom: 2rem; display: flex; gap: 1rem; flex-wrap: wrap; }
article h2 { font-size: 1.6rem; color: var(--primary); margin: 2.5rem 0 1rem; padding-bottom: 0.5rem; border-bottom: 1px solid var(--border); }
article h3 { font-size: 1.25rem; color: var(--accent); margin: 1.5rem 0 0.8rem; }
article p { margin-bottom: 1.2rem; color: var(--text); }
article ul, article ol { margin: 1rem 0 1.5rem 1.5rem; color: var(--text); }
article li { margin-bottom: 0.5rem; }
article code { background: var(--card-bg); padding: 0.2rem 0.5rem; border-radius: 4px; font-size: 0.9rem; color: var(--accent); }
article table { width: 100%; border-collapse: collapse; margin: 1.5rem 0; font-size: 0.95rem; }
article th { background: var(--card-bg); color: var(--primary); padding: 0.8rem; text-align: left; border: 1px solid var(--border); }
article td { padding: 0.8rem; border: 1px solid var(--border); color: var(--text-muted); }
article .highlight { background: var(--card-bg); border-left: 3px solid var(--primary); padding: 1rem 1.5rem; margin: 1.5rem 0; border-radius: 0 8px 8px 0; color: var(--text-muted); font-style: italic; }
article .pros-cons { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; margin: 1.5rem 0; }
article .pros, article .cons { background: var(--card-bg); border-radius: 12px; padding: 1.5rem; }
article .pros { border: 1px solid rgba(0,204,102,0.3); }
article .cons { border: 1px solid rgba(255,80,80,0.3); }
article .pros h3 { color: var(--accent); margin-top: 0; }
article .cons h3 { color: #ff5050; margin-top: 0; }
article ol.steps { counter-reset: step; margin: 1rem 0 1.5rem 1.5rem; }
article ol.steps li { counter-increment: step; margin-bottom: 1.2rem; padding-left: 0.5rem; }
article ol.steps li::marker { content: "#" counter(step) " "; color: var(--accent); font-weight: 800; }
.rank { background: var(--gradient); color: #fff; width: 40px; height: 40px; border-radius: 50%; display: inline-flex; align-items: center; justify-content: center; font-weight: 800; font-size: 1.2rem; margin-right: 1rem; vertical-align: middle; flex-shrink: 0; }
.page-title { font-size: 2.2rem; font-weight: 800; margin-bottom: 0.5rem; background: var(--gradient); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.page-desc { color: var(--text-muted); margin-bottom: 3rem; font-size: 1.1rem; }

/* === Related === */
.related { padding: 1.5rem; background: var(--card-bg); border-radius: 12px; margin: 3rem 0; }
.related h3 { color: var(--primary); margin-bottom: 1rem; }
.related ul { list-style: none; margin: 0; }
.related li { margin-bottom: 0.5rem; }
.related li::before { content: "→ "; color: var(--accent); }

/* === Footer === */
footer { text-align: center; padding: 2rem; color: var(--text-muted); font-size: 0.9rem; border-top: 1px solid var(--border); }
footer a { color: var(--primary); text-decoration: none; }
footer a:hover { text-decoration: underline; }

/* === Animations === */
@keyframes fadeInUp { from { opacity: 0; transform: translateY(30px); } to { opacity: 1; transform: translateY(0); } }
@keyframes fadeInDown { from { opacity: 0; transform: translateY(-20px); } to { opacity: 1; transform: translateY(0); } }
@keyframes pulse { 0%, 100% { opacity: 1; } 50% { opacity: 0.7; } }

/* === RESPONSIVE: Tablets & Medium Screens (max-width: 768px) === */
@media (max-width: 768px) {
    /* Header */
    header { padding: 0.75rem 1rem; }
    header nav { flex-wrap: wrap; gap: 0.5rem; }
    header .logo { font-size: 1.1rem; }
    header .nav-links { gap: 0.6rem; font-size: 0.8rem; flex-wrap: wrap; justify-content: center; }
    header .nav-links a { font-size: 0.8rem; }

    /* Hero */
    .hero { padding: 4rem 1rem; min-height: auto; }
    .hero h1 { font-size: clamp(1.6rem, 6vw, 2.4rem); }
    .hero-subtitle { font-size: 0.95rem; margin-bottom: 1.5rem; }
    .hero-badge { font-size: 0.8rem; padding: 0.4rem 1.2rem; margin-bottom: 1.2rem; }
    .price-tag { font-size: 2.2rem; }

    /* Sections */
    .section { padding: 2.5rem 1rem; }
    .section-title { font-size: 1.6rem; }
    .section-desc { font-size: 0.95rem; margin-bottom: 2rem; }

    /* Container */
    .container { padding: 1.5rem 1rem; }
    .container-narrow { padding: 1.5rem 1rem; }

    /* Features & Cards */
    .features-grid { grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 1rem; }
    .feature-card { padding: 1.5rem; }
    .feature-card h3 { font-size: 1.1rem; }
    .feature-card p { font-size: 0.9rem; }

    /* Pricing / Specs */
    .specs-grid { grid-template-columns: 1fr; gap: 1rem; }
    .spec-card { padding: 1.5rem; }
    .spec-price { font-size: 2rem; }

    /* Articles / Blog */
    .articles-grid { grid-template-columns: 1fr; gap: 1rem; }
    .article-card { padding: 1.2rem; }
    .article-card h2 { font-size: 1.1rem; }
    .article-card p { font-size: 0.9rem; }

    /* Article Detail */
    article h1 { font-size: 1.6rem; }
    article h2 { font-size: 1.3rem; margin: 2rem 0 0.8rem; }
    article h3 { font-size: 1.1rem; }
    article .pros-cons { grid-template-columns: 1fr; gap: 1rem; }
    article .pros, article .cons { padding: 1.2rem; }
    article .highlight { padding: 0.8rem 1rem; font-size: 0.9rem; }
    article ul, article ol { margin-left: 1.2rem; }

    /* Tables - horizontal scroll on mobile */
    article table { display: block; overflow-x: auto; -webkit-overflow-scrolling: touch; white-space: nowrap; font-size: 0.85rem; }
    article th, article td { padding: 0.6rem; font-size: 0.85rem; }

    /* Countries */
    .countries-grid { gap: 0.5rem; }
    .country-tag { padding: 0.5rem 1rem; font-size: 0.85rem; }

    /* Promo */
    .promo-banner { padding: 0.8rem 1.2rem; font-size: 0.85rem; flex-direction: column; text-align: center; }
    .promo-badge { font-size: 0.85rem; padding: 0.5rem 1rem; }

    /* CTA */
    .cta-button { font-size: 1rem; padding: 0.8rem 2rem; }
    .cta-section { padding: 3rem 1rem; }
    .cta-section h2 { font-size: 1.5rem; }
    .cta-section p { font-size: 0.95rem; }
    .cta-box { margin: 2rem 0; padding: 1.5rem; }
    .cta-box .cta-button { font-size: 1rem; padding: 0.8rem 1.8rem; }

    /* Page title / desc */
    .page-title { font-size: 1.6rem; }
    .page-desc { font-size: 0.95rem; margin-bottom: 2rem; }

    /* Related */
    .related { padding: 1rem; margin: 2rem 0; }
    .related h3 { font-size: 1.1rem; }

    /* Rank badge */
    .rank { width: 32px; height: 32px; font-size: 1rem; margin-right: 0.5rem; }

    /* Footer */
    footer { padding: 1.5rem 1rem; font-size: 0.8rem; }
}

/* === RESPONSIVE: Small Phones (max-width: 480px) === */
@media (max-width: 480px) {
    /* Header - stack navigation */
    header { padding: 0.6rem 0.8rem; }
    header nav { flex-direction: column; gap: 0.4rem; }
    header .logo { font-size: 1rem; }
    header .nav-links { gap: 0.5rem; justify-content: center; width: 100%; }
    header .nav-links a { font-size: 0.75rem; }

    /* Hero */
    .hero { padding: 3rem 0.8rem; min-height: auto; }
    .hero h1 { font-size: 1.4rem; }
    .hero-subtitle { font-size: 0.85rem; margin-bottom: 1rem; }
    .hero-badge { font-size: 0.7rem; padding: 0.3rem 1rem; margin-bottom: 1rem; }
    .price-tag { font-size: 1.8rem; }

    /* Sections */
    .section { padding: 2rem 0.8rem; }
    .section-title { font-size: 1.35rem; }
    .section-desc { font-size: 0.85rem; margin-bottom: 1.5rem; }

    /* Container */
    .container { padding: 1rem 0.8rem; }
    .container-narrow { padding: 1rem 0.8rem; }

    /* Features - single column */
    .features-grid { grid-template-columns: 1fr; gap: 0.8rem; }
    .feature-card { padding: 1.2rem; }
    .feature-card h3 { font-size: 1rem; }
    .feature-card p { font-size: 0.85rem; }
    svg.icon { width: 32px; height: 32px; margin-bottom: 0.6rem; }

    /* Pricing / Specs */
    .specs-grid { grid-template-columns: 1fr; gap: 0.8rem; margin-top: 1rem; }
    .spec-card { padding: 1.2rem; }
    .spec-card h3 { font-size: 1.2rem; }
    .spec-price { font-size: 1.8rem; }
    .spec-details li { font-size: 0.85rem; padding: 0.35rem 0; }
    .spec-card.featured::before { font-size: 0.6rem; padding: 0.2rem 2.5rem; top: 0.7rem; right: -2.5rem; }

    /* Articles / Blog */
    .article-card { padding: 1rem; }
    .article-card h2 { font-size: 1rem; }
    .article-card p { font-size: 0.85rem; }
    .article-card .category { font-size: 0.7rem; padding: 0.15rem 0.6rem; }
    .article-card .meta { font-size: 0.75rem; gap: 0.5rem; flex-wrap: wrap; }

    /* Article Detail */
    article h1 { font-size: 1.4rem; }
    article h2 { font-size: 1.15rem; margin: 1.5rem 0 0.6rem; }
    article h3 { font-size: 1rem; }
    article p { font-size: 0.9rem; margin-bottom: 1rem; }
    article ul, article ol { margin-left: 1rem; font-size: 0.9rem; }
    article code { font-size: 0.8rem; padding: 0.15rem 0.4rem; }
    article table { font-size: 0.8rem; }
    article th, article td { padding: 0.45rem; font-size: 0.8rem; }

    /* CTA */
    .cta-button { font-size: 0.9rem; padding: 0.7rem 1.5rem; }
    .cta-section { padding: 2.5rem 0.8rem; }
    .cta-section h2 { font-size: 1.3rem; }
    .cta-section p { font-size: 0.85rem; }
    .cta-box { margin: 1.5rem 0; padding: 1rem; }
    .cta-box .cta-button { font-size: 0.9rem; padding: 0.7rem 1.5rem; }

    /* Promo */
    .promo-banner { font-size: 0.8rem; padding: 0.6rem 1rem; }
    .promo-badge { font-size: 0.8rem; padding: 0.4rem 0.8rem; }

    /* Page title */
    .page-title { font-size: 1.4rem; }
    .page-desc { font-size: 0.85rem; margin-bottom: 1.5rem; }

    /* Countries */
    .country-tag { padding: 0.4rem 0.8rem; font-size: 0.75rem; }

    /* Footer */
    footer { padding: 1.2rem 0.8rem; font-size: 0.75rem; }

    /* Related */
    .related { padding: 0.8rem; margin: 1.5rem 0; }
    .related h3 { font-size: 1rem; }

    /* Breadcrumb */
    .breadcrumb { font-size: 0.8rem; margin-bottom: 1rem; }

    /* Rank */
    .rank { width: 28px; height: 28px; font-size: 0.85rem; margin-right: 0.3rem; }
}