/* =========================================
   CSS VARIABLES & GLOBAL SETTINGS
   ========================================= */
:root {
    /* Colors - Sky Blue Theme */
    --bg-main: #050B14; /* Slightly blue tinted dark background */
    --bg-header: rgba(5, 11, 20, 0.85);
    --bg-card: rgba(14, 165, 233, 0.05);
    --border-card: rgba(14, 165, 233, 0.15);
    
    --text-primary: #FFFFFF;
    --text-secondary: #94A3B8;
    
    --cyan: #0ea5e9; /* Sky blue */
    --cyan-hover: #0284c7; /* Darker sky blue */
    --cyan-glow: rgba(14, 165, 233, 0.3);
    
    --yellow: #F59E0B;
    --yellow-hover: #D97706;
    
    --green: #10B981;
    --red: #EF4444;

    /* Sizing & Spacing */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    
    --container-width: 1200px;
    --transition: all 0.3s ease;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', sans-serif;
}

/* Prevent iOS auto-zoom on input focus */
input, textarea, select {
    font-size: 16px !important;
}

html { 
    scroll-behavior: smooth; 
    overflow-x: hidden !important;
    width: 100%;
    max-width: 100%;
}

body {
    background-color: var(--bg-main);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden !important;
    width: 100%;
    max-width: 100%;
    position: relative;
}

/* Background subtle glow effect */
body::before {
    content: '';
    position: absolute;
    top: -10%;
    left: 50%;
    transform: translateX(-50%);
    width: 100%;
    max-width: 800px;
    height: 800px;
    background: radial-gradient(circle, rgba(14, 165, 233, 0.15) 0%, rgba(5, 11, 20, 0) 70%);
    z-index: -1;
    pointer-events: none;
}

/* =========================================
   TYPOGRAPHY & UTILITIES
   ========================================= */
a, button { 
    text-decoration: none; 
    color: inherit; 
    touch-action: manipulation; /* Prevent double-tap zoom */
}
input, select, textarea {
    touch-action: manipulation;
}
ul { list-style: none; }

.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 2rem;
}

.section { padding: 5rem 0; }
.center { text-align: center; }
.flex-between { display: flex; justify-content: space-between; align-items: center; }

/* Text colors */
.text-cyan { color: var(--cyan); }
.text-yellow { color: var(--yellow); }
.text-success { color: var(--green); }
.text-bold { font-weight: 600; }

.section-header { margin-bottom: 3rem; }
.section-title { font-size: 2.25rem; font-weight: 700; margin-bottom: 0.5rem; }
.section-subtitle { color: var(--text-secondary); font-size: 1.1rem; max-width: 600px; margin: 0 auto; }

/* Grid Layouts */
.grid { display: grid; gap: 2rem; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }

/* =========================================
   BUTTONS
   ========================================= */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
}

.btn-full { width: 100%; }

.btn-zalo {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    text-align: left;
    line-height: 1.3;
}

@media (max-width: 480px) {
    .btn-zalo {
        font-size: 0.85rem;
        padding: 0.6rem 0.5rem;
        gap: 6px;
    }
    .btn-zalo img {
        width: 20px !important;
        height: 20px !important;
    }
}

.btn-primary {
    background: var(--cyan);
    color: white;
}
.btn-primary:hover { background: var(--cyan-hover); box-shadow: 0 0 15px var(--cyan-glow); }

.btn-outline {
    background: transparent;
    border-color: var(--border-card);
    color: var(--text-primary);
}
.btn-outline:hover { border-color: var(--cyan); color: var(--cyan); }

.btn-secondary {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-secondary);
}
.btn-secondary:hover { background: rgba(255, 255, 255, 0.1); color: white; }

.btn-cyan { background: var(--cyan); color: white; }
.btn-cyan:hover { transform: translateY(-2px); box-shadow: 0 5px 15px var(--cyan-glow); }

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

.glow-effect { box-shadow: 0 0 20px rgba(245, 158, 11, 0.3); }
.glow-effect:hover { box-shadow: 0 0 30px rgba(245, 158, 11, 0.5); transform: scale(1.05); }

/* =========================================
   HEADER / NAVBAR
   ========================================= */
.header {
    position: fixed;
    top: 0; left: 0; width: 100%;
    z-index: 1000;
    background: var(--bg-header);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-card);
    transition: var(--transition);
}

.header-container {
    position: relative;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo { font-size: 1.5rem; font-weight: 800; letter-spacing: -0.5px; }

.nav-links { display: flex; gap: 2rem; }
@media (min-width: 769px) {
    .nav-links { position: absolute; left: 50%; transform: translateX(-50%); }
}
.nav-links a { color: var(--text-secondary); font-weight: 500; transition: var(--transition); }
.nav-links a:hover { color: var(--cyan); }

.mobile-menu-toggle {
    display: none;
    background: none; border: none; cursor: pointer;
    flex-direction: column; gap: 5px;
}
.mobile-menu-toggle span { display: block; width: 25px; height: 2px; background: white; transition: 0.3s; }

/* =========================================
   HERO SECTION
   ========================================= */
.hero {
    padding-top: 150px;
    padding-bottom: 4rem;
    text-align: center;
}

.hero-badge {
    display: inline-block;
    padding: 0.5rem 1rem;
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    color: var(--cyan);
    border-radius: 50px;
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
}

.hero-title {
    font-size: 3.5rem;
    line-height: 1.2;
    margin-bottom: 1.5rem;
}

.text-gradient {
    background: linear-gradient(to right, #7dd3fc, var(--cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-desc {
    font-size: 1.125rem;
    color: var(--text-secondary);
    max-width: 650px;
    margin: 0 auto 2.5rem;
}

.hero-actions { display: flex; gap: 1rem; justify-content: center; }

/* =========================================
   TICKER
   ========================================= */
.ticker-wrapper {
    background: #040906;
    border-top: 1px solid var(--border-card);
    border-bottom: 1px solid var(--border-card);
    overflow: hidden;
    white-space: nowrap;
    display: flex;
    align-items: center;
    padding: 8px 0;
    width: 100%;
    max-width: 100%;
}
.ticker-track {
    display: flex;
    align-items: center;
    animation: scrollTicker 25s linear infinite;
}
.ticker-content {
    display: flex;
    align-items: center;
}
.ticker-item {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    color: var(--text-secondary);
    font-size: 0.95rem;
    padding: 0.75rem 2.5rem;
}
.ticker-item strong { color: white; font-weight: 600; }
.ticker-zalo {
    width: 20px; height: 20px;
    background: #0068FF;
    border-radius: 4px;
    display: inline-flex; align-items: center; justify-content: center;
}

@keyframes scrollTicker {
    0% { transform: translateX(0); }
    100% { transform: translateX(-50%); }
}

/* =========================================
   COMMON CARDS (Glassmorphism)
   ========================================= */
.card {
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-lg);
    padding: 2rem;
    backdrop-filter: blur(10px);
    transition: var(--transition);
}
.card:hover {
    transform: translateY(-5px);
    border-color: var(--cyan-glow);
    box-shadow: 0 10px 30px rgba(16, 163, 127, 0.2);
}

/* =========================================
   VALUE PROP SECTION
   ========================================= */
.value-card { text-align: center; }
.value-card .card-icon { font-size: 2.5rem; margin-bottom: 1rem; }
.value-card h3 { margin-bottom: 0.75rem; font-size: 1.25rem; }
.value-card p { color: var(--text-secondary); font-size: 0.95rem; }

/* =========================================
   COURSES SECTION
   ========================================= */
.course-card { padding: 0; overflow: hidden; display: flex; flex-direction: column; height: 100%; }
.course-image {
    height: 180px; width: 100%;
    display: flex; align-items: center; justify-content: center; overflow: hidden;
}
.course-image img { width: 100%; height: 100%; object-fit: cover; }
.course-content { padding: 1.5rem; position: relative; display: flex; flex-direction: column; flex-grow: 1; }
.badge-vip {
    position: absolute; top: -12px; right: 1.5rem;
    background: var(--yellow); color: white;
    font-size: 0.75rem; font-weight: bold;
    padding: 2px 10px; border-radius: 4px;
}
.course-rating { color: var(--yellow); font-size: 0.85rem; margin-bottom: 0.5rem; }
.course-rating span { color: var(--text-secondary); }
.course-title { font-size: 1.2rem; margin-bottom: 0.5rem; }
.course-desc { color: var(--text-secondary); font-size: 0.9rem; margin-bottom: 1.5rem; line-height: 1.5; flex-grow: 1; }

/* =========================================
   TOOLS SECTION
   ========================================= */
.tool-card { position: relative; }
.tool-card.hot-item {
    border-color: rgba(239, 68, 68, 0.4);
    box-shadow: 0 0 20px rgba(239, 68, 68, 0.1);
}
.tool-card.hot-item:hover {
    border-color: rgba(239, 68, 68, 0.7);
    box-shadow: 0 0 30px rgba(239, 68, 68, 0.2);
    transform: translateY(-5px);
}

.tool-badge {
    padding: 0.25rem 0.75rem; border-radius: 20px;
    font-size: 0.75rem; font-weight: 600;
    display: inline-flex; align-items: center; gap: 6px;
    white-space: nowrap; flex-shrink: 0;
}
.tool-badge .dot { width: 6px; height: 6px; border-radius: 50%; }

.status-active { background: rgba(16, 185, 129, 0.1); color: var(--green); border: 1px solid rgba(16,185,129,0.3); }
.status-active .dot { background: var(--green); }
.status-warning { background: rgba(245, 158, 11, 0.1); color: var(--yellow); border: 1px solid rgba(245,158,11,0.3); }
.status-warning .dot { background: var(--yellow); }
.hot-badge { background: rgba(239, 68, 68, 0.1); color: var(--red); border: 1px solid rgba(239, 68, 68, 0.3); }
.hot-badge .dot { background: var(--red); }

.tool-header-row { display: flex; justify-content: space-between; align-items: flex-start; gap: 12px; margin-bottom: 1rem; }
.tool-title-group { display: flex; align-items: center; gap: 10px; flex: 1; }
.tool-icon { width: 45px; height: 45px; border-radius: 10px; background: rgba(255,255,255,0.05); display: flex; align-items: center; justify-content: center; font-size: 1.5rem; flex-shrink: 0; }
.tool-name { font-size: 1.15rem; line-height: 1.3; }
.tool-rating { font-size: 0.85rem; color: var(--text-secondary); margin-bottom: 1.5rem; }

.tool-pricing {
    background: rgba(0,0,0,0.2); padding: 1rem; border-radius: var(--radius-md); text-align: center; margin-bottom: 1.5rem;
}
.price-old { text-decoration: line-through; color: var(--text-secondary); font-size: 0.85rem; }
.price-new { font-size: 1.5rem; font-weight: bold; }
.price-new span { font-size: 0.9rem; font-weight: normal; color: var(--text-secondary); }

.tool-actions { display: flex; flex-direction: column; gap: 0.75rem; }
.btn-zalo { display: flex; align-items: center; justify-content: center; gap: 8px; font-weight: 700; }

/* =========================================
   TESTIMONIALS
   ========================================= */
.review-card { padding: 2rem; }
.reviewer-info { display: flex; align-items: center; gap: 1rem; }
.avatar { width: 40px; height: 40px; background: rgba(255,255,255,0.1); border-radius: 50%; display: flex; align-items: center; justify-content: center; font-size: 1.2rem; }
.reviewer-info h4 { font-size: 1rem; margin-bottom: 2px; }
.verify-badge { font-size: 0.8rem; }
.review-text { font-style: italic; color: var(--text-secondary); font-size: 0.95rem; }

/* =========================================
   FINAL CTA
   ========================================= */
.cta-box {
    border: 1px dashed var(--cyan);
    border-radius: var(--radius-lg);
    padding: 4rem 2rem;
    background: radial-gradient(circle, rgba(6, 182, 212, 0.05) 0%, transparent 100%);
}
.btn-large { font-size: 1.1rem; padding: 1rem 2rem; border-radius: 50px; margin-top: 1rem; }

/* =========================================
   FOOTER
   ========================================= */
.footer { border-top: 1px solid var(--border-card); padding-top: 4rem; background: #070A12; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 3rem; margin-bottom: 3rem; }
.footer-desc { color: var(--text-secondary); font-size: 0.9rem; margin-top: 1rem; max-width: 300px; }
.footer h4 { margin-bottom: 1.5rem; font-size: 1.1rem; }
.footer ul li { margin-bottom: 0.75rem; }
.footer ul li a { color: var(--text-secondary); font-size: 0.9rem; transition: var(--transition); }
.footer ul li a:hover { color: var(--cyan); }
.contact-list li { color: var(--text-secondary); font-size: 0.9rem; }
.footer-bottom { border-top: 1px solid var(--border-card); padding: 1.5rem 0; text-align: center; color: var(--text-secondary); font-size: 0.85rem; }
.disclaimer { font-size: 0.75rem; opacity: 0.6; margin-top: 0.5rem; }

/* =========================================
   FLOATING BUTTONS
   ========================================= */
.floating-contact { position: fixed; bottom: 30px; left: 30px; z-index: 99; display: flex; flex-direction: column; gap: 15px; }
.float-btn {
    height: 55px; border-radius: 50px;
    display: inline-flex; align-items: center; justify-content: center;
    box-shadow: 0 4px 15px rgba(0,0,0,0.3); transition: transform 0.3s;
    background: #0068FF; color: white; padding: 0 20px 0 5px; gap: 10px; font-weight: 600; white-space: nowrap;
}
.float-btn:hover { transform: scale(1.05); }
.zalo-float-icon { width: 45px; height: 45px; border-radius: 50%; }

/* =========================================
   MODAL (PAYMENT)
   ========================================= */
.modal-overlay {
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(5px);
    z-index: 2000;
    display: none; /* hidden by default */
    align-items: center;
    justify-content: center;
    padding: 20px;
}
.modal-overlay.active {
    display: flex;
}
.modal-content {
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    border-radius: var(--radius-lg);
    width: 100%;
    max-width: 450px;
    padding: 2rem;
    position: relative;
    box-shadow: 0 10px 40px rgba(0,0,0,0.5);
    animation: modalSlideUp 0.3s ease;
}
@keyframes modalSlideUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}
.modal-close {
    position: absolute;
    top: 15px; right: 15px;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-size: 1.8rem;
    cursor: pointer;
    line-height: 1;
}
.modal-close:hover { color: white; }

.tier-btn {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(16, 163, 127, 0.3);
    border-radius: 12px;
    padding: 1.2rem;
    cursor: pointer;
    transition: all 0.2s ease;
    width: 100%;
    color: white;
    margin-bottom: 0.8rem;
}
.tier-btn:hover {
    background: rgba(16, 163, 127, 0.08);
    border-color: var(--cyan);
    transform: translateY(-2px);
}

.tier-best {
    background: linear-gradient(to right, rgba(16, 163, 127, 0.1), rgba(16, 163, 127, 0.05));
    border: 1px solid var(--cyan);
    box-shadow: 0 4px 15px rgba(16, 163, 127, 0.15);
}

.tier-left {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    text-align: left;
}

.tier-radio {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    border: 2px solid var(--text-secondary);
    margin-top: 2px;
    flex-shrink: 0;
    transition: var(--transition);
}
.tier-btn:hover .tier-radio, .tier-best .tier-radio {
    border-color: var(--cyan);
    background: var(--cyan);
    box-shadow: inset 0 0 0 4px var(--bg-card);
}

.tier-info {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.tier-name {
    font-weight: 600;
    font-size: 1.05rem;
}

.tier-badge {
    display: inline-block;
    background: rgba(16, 163, 127, 0.15);
    color: var(--cyan);
    font-size: 0.75rem;
    padding: 3px 8px;
    border-radius: 4px;
    font-weight: 600;
    margin-top: 2px;
}

.tier-right {
    text-align: right;
    display: flex;
    flex-direction: column;
    align-items: flex-end;
}

.tier-price {
    color: var(--cyan);
    font-size: 1.1rem;
    font-weight: 700;
    white-space: nowrap;
}

.tier-sub {
    color: var(--text-secondary);
    font-size: 0.8rem;
    margin-top: 2px;
}

/* =========================================
   RESPONSIVE DESIGN (MOBILE/TABLET)
   ========================================= */
.show-mobile { display: none; }

@media (max-width: 992px) {
    .grid-3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
    .grid-3 { grid-template-columns: 1fr; }
    .footer-grid { grid-template-columns: 1fr; gap: 2rem; }
    
    .hero-title { font-size: 2.2rem; }
    .hero-badge { font-size: 0.75rem; padding: 0.4rem 0.8rem; white-space: normal; text-align: center; }
    .hero-actions { flex-direction: column; }
    
    .nav-links {
        position: absolute; top: 70px; left: 0; width: 100%;
        background: var(--bg-header); border-bottom: 1px solid var(--border-card);
        flex-direction: column; gap: 0; padding: 1rem 0;
        display: none;
    }
    .nav-links.active { display: flex; }
    .nav-links a { padding: 1rem 2rem; border-bottom: 1px solid rgba(255,255,255,0.05); }
    
    .mobile-menu-toggle { display: flex; }
    .login-btn { display: none; }
    
    .hidden-mobile { display: none; }
    .show-mobile { display: block; }
    
    .tool-actions { grid-template-columns: 1fr; }
    
    .floating-contact { bottom: 30px; left: 15px; z-index: 999; }
    .float-btn { height: 45px; padding: 0 15px 0 4px; font-size: 0.9rem; }
    .zalo-float-icon { width: 37px; height: 37px; }
}

@media (max-width: 576px) {
    /* Payment Modal */
    .modal-overlay {
        padding: 10px;
    }
    .modal-content {
        padding: 1.2rem;
        max-height: 90vh;
        overflow-y: auto;
        width: 100%;
        max-width: calc(100vw - 20px);
        margin: 0 auto;
        box-sizing: border-box;
    }
    .modal-title { font-size: 1.3rem; margin-bottom: 1rem !important; }
    
    .tier-btn {
        padding: 1rem;
        width: 100%;
        box-sizing: border-box;
    }
    .tier-name {
        font-size: 0.95rem;
    }
    .tier-price {
        font-size: 1rem;
    }
    
    #modal-package-name { font-size: 1.1rem !important; word-break: break-word; }
    #modal-package-price { font-size: 1.3rem !important; }
}