:root {
    --font-main: 'Inter', sans-serif;
    --font-heading: 'Montserrat', sans-serif;
    --bg-main: #FCFAF2; 
    --bg-panel: rgba(255, 255, 255, 0.98); 
    
    --text-main: #1F2937; 
    --text-muted: #4B5563; 
    --text-light: #FFFFFF; 
    
    --primary: #FFBC00; /* Vàng tươi rực rỡ chuẩn nhận diện thương hiệu Hikorean */
    --primary-light: #FFD24D;
    --primary-dark: #E6A800;
    --primary-glow: rgba(255, 188, 0, 0.3);
    --primary-contrast: #111827; /* Vì nền vàng sáng nên text phải là màu đen sẫm để nổi tối đa */
    
    --accent: #ef4444; /* Vẫn giữ tí đỏ tươi cho máu lửa */
    
    --bg-dark: #111827; 
    --brand-border: rgba(255, 188, 0, 0.4); 
    --surface-border: rgba(31, 41, 55, 0.1); 
    
    --transition: all 0.2s ease-in-out;
}

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

body {
    font-family: var(--font-main);
    color: var(--text-main);
    background-color: var(--bg-main);
    background-image:
        radial-gradient(circle at 10% 20%, rgba(212, 175, 55, 0.05) 0%, transparent 40%),
        radial-gradient(circle at 90% 80%, rgba(121, 85, 72, 0.05) 0%, transparent 40%);
    background-attachment: fixed;
    line-height: 1.6;
    overflow-x: hidden;
}

h1, h2, h3, h4, .logo-text {
    font-family: var(--font-heading);
    line-height: 1.2;
    color: var(--text-main);
}

a { text-decoration: none; }

/* TYPOGRAPHY UTILS */
.text-center { text-align: center; }
.highlight { color: var(--primary); }
.highlight-red { color: #f87171; }
.text-gradient { color: var(--primary-dark); }
p.lead-text { font-size: 1.2rem; font-weight: 400; margin-bottom: 2rem; color: var(--text-muted); }

/* LAYOUT */
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }
.max-w-800 { max-width: 800px; margin: 0 auto; }
section { padding: 4rem 0; position: relative; }
.flex-row { display: flex; flex-wrap: wrap; gap: 2rem; }
.items-center { align-items: center; }
.items-stretch { align-items: stretch; }
.col-half { flex: 1 1 45%; }
.mt-3 { margin-top: 1.5rem; }
.mb-3 { margin-bottom: 1.5rem; }
.img-fluid { max-width: 100%; height: auto; border-radius: 12px; }

/* REUSABLE STYLES */
.dark-mode { background-color: var(--bg-dark); color: var(--text-light); }
.dark-mode h1, .dark-mode h2, .dark-mode h3, 
.dark-mode p, .dark-mode .text-muted, .dark-mode li { color: var(--text-light) !important; }

/* PERFORMANCE CARDS */
.glass-header {
    position: fixed; top: 0; width: 100%; z-index: 1000;
    background: var(--bg-panel);
    border-bottom: 2px solid var(--primary);
    box-shadow: 0 4px 15px rgba(62, 39, 35, 0.05);
}
.glass-card, .glass-box, .glass-form {
    background: var(--bg-panel);
    border: 2px solid var(--surface-border);
    border-radius: 16px;
    padding: 2rem;
    box-shadow: 0 4px 15px rgba(62, 39, 35, 0.05);
    transition: transform 0.25s ease-out, box-shadow 0.25s ease-out;
}
.glass-card:hover {
    transform: translateY(-2px);
    border-color: var(--primary);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.08);
}
.dark-mode .glass-card, .dark-mode .glass-form {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--brand-border);
}

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

/* BUTTONS */
.btn {
    display: inline-block; padding: 14px 32px; border-radius: 50px;
    font-weight: 800; text-transform: uppercase; letter-spacing: 0.5px;
    cursor: pointer; transition: var(--transition); border: none; outline: none;
}
.btn-primary { 
    background: var(--primary); 
    color: var(--primary-contrast); 
    box-shadow: 0 4px 0 var(--primary-dark); 
}
.btn-primary:hover { 
    background: var(--primary-light); 
    transform: translateY(2px); 
    box-shadow: 0 2px 0 var(--primary-dark); 
    color: var(--text-main);
}
.btn-full { width: 100%; display: block; padding: 18px; font-size: 1.1rem; }

/* HERO SECTION */
.hero { min-height: 100vh; display: flex; align-items: center; padding-top: 100px; background-color: var(--bg-main); border-bottom: 1px solid rgba(0,0,0,0.05); }

.hero-content { position: relative; z-index: 1; display: flex; flex-wrap: wrap; gap: 4rem; align-items: center; }
.hero-text { flex: 1 1 50%; }
.badge { display: inline-block; padding: 8px 16px; background: var(--primary-glow); color: var(--primary-dark); border: 1px solid var(--primary); border-radius: 50px; font-weight: 700; font-size: 0.95rem; margin-bottom: 20px; text-transform: uppercase; }
.headline { font-size: 3.2rem; margin-bottom: 15px; color: var(--text-main); }
.sub-headline { font-size: 1.6rem; font-weight: 500; color: var(--text-muted); margin-bottom: 20px; }
.intro { font-size: 1.1rem; margin-bottom: 30px; color: var(--text-main); }

.teacher-info { display: flex; align-items: center; gap: 15px; margin-bottom: 20px; padding: 12px 20px; background: var(--bg-panel); border-radius: 50px; display: inline-flex; border: 1px solid var(--surface-border); box-shadow: 0 4px 10px rgba(0,0,0,0.05); }
.teacher-img { width: 60px; height: 60px; border-radius: 50%; object-fit: cover; border: 3px solid var(--primary); background: white; }
.teacher-details { display: flex; flex-direction: column; }
.teacher-role { font-size: 0.85rem; color: var(--text-muted); font-weight: 600; }
.teacher-name { font-weight: 800; color: var(--primary-dark); font-size: 1.1rem; }

.hero-image { flex: 1 1 40%; position: relative; }
.image-card { padding: 12px; position: relative; border: 2px solid var(--primary); background: var(--bg-panel); border-radius: 16px; box-shadow: 0 8px 25px var(--primary-glow); }
.main-img { width: 100%; border-radius: 12px; display: block; }
.floating-badge { position: absolute; background: var(--primary); color: var(--primary-contrast); padding: 10px 20px; border-radius: 50px; font-weight: 800; z-index: 2; display: flex; align-items: center; gap: 8px; border: 2px solid var(--primary-contrast); box-shadow: 0 4px 10px rgba(0,0,0,0.2); }
.floating-badge i { color: var(--primary-contrast); }
.badge-1 { top: -20px; right: -20px; }
.badge-2 { bottom: 30px; left: -30px; }

/* PAIN POINTS */
.section-title { font-size: 2.5rem; margin-bottom: 2rem; color: var(--text-main); font-weight: 800; }
.pain-list { list-style: none; }
.pain-list li { display: flex; gap: 15px; margin-bottom: 20px; background: var(--bg-panel); padding: 20px; border-radius: 12px; border: 1px solid var(--surface-border); border-left: 4px solid var(--accent); box-shadow: 0 4px 10px rgba(0,0,0,0.03); }
.pain-list i { color: var(--accent); font-size: 1.5rem; margin-top: 3px; }
.alert-card { background: var(--bg-panel); color: var(--text-main); border: 2px solid var(--primary); border-left: 8px solid var(--primary); border-radius: 12px; padding: 2rem; box-shadow: 0 8px 20px rgba(212, 175, 55, 0.15); margin-top: 30px; }
.alert-card h3 { color: var(--primary-dark); margin-bottom: 1.5rem; display: flex; align-items: center; gap: 10px; font-size: 1.3rem; }
.alert-card p { margin-bottom: 1rem; color: var(--text-main); font-weight: 500; }
.conclusion { margin-top: 2rem; font-weight: 800; font-size: 1.2rem; color: var(--primary-contrast); background: var(--primary); padding: 15px; border-radius: 8px; text-align: center; }

/* SOLUTION */
.solution { background-color: var(--bg-panel); border-top: 2px solid var(--surface-border); border-bottom: 1px solid var(--surface-border); }
.solution h2 { font-size: 2.8rem; margin-bottom: 1.5rem; color: var(--text-main); }
.highlight-box { background: var(--bg-main); border: 2px dashed var(--primary); padding: 3rem; border-radius: 20px; }
.highlight-box p { font-size: 1.4rem; margin-bottom: 2rem; color: var(--text-main); font-weight: 500; }
.highlight-box strong { font-family: var(--font-heading); }
.gift-banner { background: var(--primary); padding: 15px 30px; border-radius: 50px; font-weight: 800; color: var(--primary-contrast); display: inline-block; box-shadow: 0 4px 15px var(--primary-glow); }

/* SCHEDULE */
.timeline { display: grid; grid-template-columns: repeat(auto-fit, minmax(350px, 1fr)); gap: 3rem; max-width: 1000px; margin: 3rem auto 0; position: relative; }
.timeline-item { width: 100%; position: relative; }
.day-badge { position: absolute; top: -20px; left: 30px; width: 90px; height: 40px; background: var(--primary); color: var(--primary-contrast); font-weight: 800; font-size: 1.1rem; border-radius: 50px; display: flex; align-items: center; justify-content: center; z-index: 2; border: 2px solid white; box-shadow: 0 4px 10px rgba(212, 175, 55, 0.4); }

.module-card { padding-top: 2.5rem; }
.module-card h3 { color: var(--text-main); margin-bottom: 1.5rem; display: flex; align-items: flex-start; gap: 10px; font-size: 1.3rem; font-weight: 800; line-height: 1.4; }
.module-card ul { list-style: none; text-align: left; }
.module-card ul li { margin-bottom: 1rem; position: relative; font-weight: 500; color: var(--text-muted); padding-left: 20px; font-size: 1.05rem; }
.module-card ul li::before { content: '•'; color: var(--accent); position: absolute; left: 0; top: 0; font-size: 1.5rem; line-height: 1; }
.highlight-module { background: #FCFAF2; border: 2px solid var(--primary); }

/* TAKEAWAYS & GIFTS */
.takeaways { background: var(--bg-panel); border-top: 1px solid var(--surface-border); }
.outcome-card h3, .gift-card h3 { color: var(--primary-dark); margin-bottom: 1.5rem; font-size: 1.6rem; font-weight: 800; }
.check-list { list-style: none; }
.check-list li { margin-bottom: 15px; display: flex; gap: 10px; color: var(--text-main); font-size: 1.05rem; }
.check-list i { color: var(--primary); margin-top: 5px; }

.gift-card { background: var(--bg-panel); border: 2px solid var(--primary); }
.gift-list { display: flex; flex-direction: column; gap: 12px; }
.gift-item { background: rgba(212,175,55,0.05); padding: 16px; border-radius: 8px; font-weight: 700; color: var(--primary-dark); display: flex; align-items: center; gap: 12px; font-size: 1.1rem; border: 1px dashed var(--primary); }

/* REGISTER FORM */
.register { padding: 5rem 0; background-color: var(--bg-main); border-top: 2px dashed var(--primary); }
.form-info h2 { font-size: 2.8rem; margin-bottom: 2rem; color: var(--text-main); }
.event-details { display: flex; flex-direction: column; gap: 15px; }
.detail-item { display: flex; align-items: center; gap: 15px; background: var(--bg-panel); padding: 15px; border-radius: 12px; border-left: 4px solid var(--primary); box-shadow: 0 4px 10px rgba(0,0,0,0.02); }
.detail-item i { font-size: 1.8rem; color: var(--primary); }
.detail-item strong { color: var(--text-main); display: block; font-size: 1.1rem; }
.detail-item p { color: var(--text-muted); margin: 0; }

.requirement-box { background: var(--bg-panel); border: 1px solid var(--surface-border); padding: 20px; border-radius: 12px; margin-top: 20px;}
.requirement-box h4 { color: var(--primary-dark); margin-bottom: 10px; }
.requirement-box ul { padding-left: 20px; color: var(--text-main); }

.glass-form { background: var(--bg-panel); border: 2px solid var(--primary); }
.glass-form h3 { color: var(--text-main); margin-bottom: 1.5rem; font-size: 1.5rem; text-align: center; font-weight: 800; }
.input-group { margin-bottom: 1.2rem; }
.input-group label { display: block; margin-bottom: 6px; color: var(--text-muted); font-size: 0.95rem; font-weight: 700; }
.input-group input, .input-group select { width: 100%; padding: 14px 16px; border-radius: 8px; border: 1px solid var(--surface-border); background: var(--bg-main); color: var(--text-main); font-family: inherit; font-size: 1rem; transition: var(--transition); }
.input-group input:focus, .input-group select:focus { outline: none; border-color: var(--primary); background: #ffffff; box-shadow: 0 0 0 3px var(--primary-glow); }
.input-group select option { background: #ffffff; color: var(--text-main); }

/* FOOTER */
.footer { background: #1a100e; padding: 4rem 0 2rem; color: rgba(255,255,255,0.6); border-top: 4px solid var(--primary); }
.footer h3 { color: var(--text-light); font-size: 1.6rem; margin-bottom: 15px; }
.footer-perks span { font-size: 1.1rem; color: var(--text-light); }
.footer-logo { display: inline-block; padding: 10px; background: rgba(255,255,255,0.05); border-radius: 8px; border: 1px solid rgba(255,255,255,0.1); margin-bottom: 15px; }
.copyright { font-size: 0.9rem; margin-top: 20px; border-top: 1px solid rgba(255,255,255,0.1); padding-top: 20px; }

/* BỎ HIỆU ỨNG ANIMATION CỒNG KỀNH GÂY LAG */
.is-visible { opacity: 1 !important; transform: none !important; }

/* IMAGE ACCENTS - Tối ưu hóa kích thước */
.img-collage { position: relative; height: 100%; min-height: 350px; }
.img-collage .img-1 { position: absolute; top: 0; left: 0; width: 75%; z-index: 1; border-radius: 12px; border: 4px solid var(--primary); box-shadow: 0 8px 20px rgba(0,0,0,0.1); }
.img-collage .img-2 { position: absolute; bottom: 0; right: 0; width: 55%; z-index: 2; border-radius: 12px; border: 4px solid white; box-shadow: 0 8px 20px rgba(0,0,0,0.1); }
.decorated-heading { position: relative; display: inline-block; padding-bottom: 10px; border-bottom: 4px solid var(--primary); }

/* RESPONSIVE */
@media (max-width: 992px) {
    .headline { font-size: 2.5rem; }
    .hero-content { flex-direction: column; text-align: center; }
    .teacher-info { margin: 0 auto 30px; }
    .hero-image { width: 100%; max-width: 500px; }
    .timeline::before { left: 30px; }
    .timeline-item { width: 100%; text-align: left !important; padding-left: 70px; }
    .day-badge { left: 0 !important; top: 0; width: 60px; height: 40px; border-radius: 8px; }
    .timeline-item:nth-child(even) .module-card ul li::before, .timeline-item:nth-child(odd) .module-card ul li::after { display: none; }
    .module-card ul li { padding: 0 0 0 20px !important; }
    .module-card ul li::before { content: '•'; color: var(--primary); position: absolute; left: 0; font-size: 1.5rem; line-height: 1; display: block !important; }
    .timeline-item:nth-child(odd) .module-card h3 { justify-content: flex-start; }
    .img-collage { min-height: 300px; margin-top: 20px; }
}

@media (max-width: 768px) {
    .col-half { flex: 1 1 100%; }
    .headline { font-size: 2rem; }
    .sub-headline { font-size: 1.3rem; }
    .section-title, .solution h2, .form-info h2 { font-size: 1.8rem; }
}