/* Reset & Variables */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary: #8a63f7;
    --primary-dark: #6340ce;
    --secondary: #f39c12;
    --text-main: #2d3436;
    --text-light: #636e72;
    --bg-light: #fdfbf7;
    --bg-white: #ffffff;
    --gradient-purple: linear-gradient(135deg, #5b46d0, #9d7cfb);
}

body {
    font-family: 'Be Vietnam Pro', sans-serif;
    color: var(--text-main);
    line-height: 1.6;
    background-color: var(--bg-white);
    overflow-x: hidden;
}

/* Typography Classes */
h1, h2, h3, h4 {
    font-weight: 700;
    line-height: 1.3;
}

h1 {
    font-size: 3.5rem;
    margin-bottom: 1rem;
    color: #fff;
    letter-spacing: -1px;
}

h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

h3 {
    font-size: 1.4rem;
    margin-bottom: 0.5rem;
}

p {
    font-size: 1.1rem;
    color: var(--text-light);
}

.text-orange { color: var(--secondary); font-size: 0.9rem; letter-spacing: 2px; }
.text-purple { color: var(--primary); font-size: 0.9rem; letter-spacing: 2px; }

/* Utilities */
.container {
    width: 100%;
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

.btn {
    display: inline-block;
    padding: 14px 28px;
    font-family: 'Be Vietnam Pro', sans-serif;
    font-weight: 600;
    font-size: 1.1rem;
    border-radius: 50px;
    text-decoration: none;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
}

.btn-primary {
    background-color: var(--bg-white);
    color: var(--primary-dark);
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(255,255,255,0.2);
}

.btn-submit {
    background-color: var(--primary);
    color: white;
    width: 100%;
    margin-top: 10px;
}

.btn-submit:hover {
    background-color: var(--primary-dark);
}

.btn-zalo {
    background-color: #0088ff;
    color: white;
    margin-top: 15px;
    display: inline-block;
}

.btn-zalo:hover {
    background-color: #0066cc;
}

/* Hero Section */
.hero-section {
    position: relative;
    padding: 120px 0;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    /* User wanted the image as background */
    background: url('./assets/bg_brain.png') no-repeat center center;
    background-size: cover;
}

/* Semi-transparent overlay to ensure text is highly readable */
.hero-overlay {
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(30, 20, 60, 0.3); /* Giảm độ đậm của lớp phủ tím để lộ rõ hình não phát sáng */
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    color: white;
}

.hero-content p {
    color: rgba(255, 255, 255, 0.9);
}

.chip {
    display: inline-block;
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,0.3);
    padding: 8px 20px;
    border-radius: 50px;
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: 20px;
}

.hero-content .subtitle {
    font-size: 1.25rem;
    max-width: 600px;
    margin: 0 auto 40px auto;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 60px;
    margin-bottom: 50px;
}

.stat-item h3 {
    font-size: 2.5rem;
    margin-bottom: 0;
    color: white;
}

.stat-item p {
    font-size: 0.95rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* Problem Section */
.problem-section {
    padding: 100px 0;
    background-color: var(--bg-light);
    text-align: center;
}

.section-heading {
    max-width: 700px;
    margin: 0 auto 60px auto;
}

.section-heading p {
    font-size: 1.15rem;
}

.grid-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.card {
    background: white;
    padding: 40px 30px;
    border-radius: 20px;
    box-shadow: 0 10px 40px rgba(0,0,0,0.04);
    text-align: left;
    transition: transform 0.3s ease;
    border: 1px solid rgba(0,0,0,0.02);
}

.card:hover {
    transform: translateY(-5px);
}

.card-icon {
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.pretty-text {
    text-wrap: pretty; /* Đảm bảo không có chữ nào bị rớt mồ côi 1 dòng */
}

/* Solution Section */
.solution-section {
    padding: 100px 0;
    background: white;
}

.solution-layout {
    display: flex;
    align-items: center;
    gap: 60px;
}

.solution-image {
    flex: 1;
}

.ebook-html-cover {
    width: 100%;
    max-width: 380px;
    aspect-ratio: 3 / 4.5;
    margin: 0 auto;
    border-radius: 5px 15px 15px 5px;
    box-shadow: -5px 0 10px rgba(0,0,0,0.2) inset, 15px 20px 40px rgba(0,0,0,0.3);
    position: relative;
    overflow: hidden;
    background: url('./assets/bg_brain.png') no-repeat center center;
    background-size: cover;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    transform: perspective(1000px) rotateY(-5deg);
    transition: transform 0.3s ease;
}

.ebook-html-cover::before {
    content: '';
    position: absolute;
    left: 0; top: 0; bottom: 0;
    width: 15px;
    background: linear-gradient(to right, rgba(255,255,255,0.4), rgba(255,255,255,0.1), transparent);
    z-index: 2;
}

.ebook-html-cover:hover {
    transform: perspective(1000px) rotateY(0deg) scale(1.02);
}

.cover-text-circle {
    background: rgba(255,255,255,0.9);
    width: 220px;
    height: 220px;
    border-radius: 50%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    box-shadow: 0 10px 40px rgba(0,0,0,0.6);
    z-index: 3;
    text-align: center;
    padding: 20px;
}

.cover-top {
    font-size: 1.8rem;
    color: #ff477e;
    font-weight: 500;
}

.cover-bottom {
    font-size: 2.2rem;
    color: #ff477e;
    font-weight: 800;
    line-height: 1.1;
    margin-top: 5px;
}

.cover-author {
    position: absolute;
    bottom: 25px;
    color: rgba(255,255,255,0.9);
    font-size: 1rem;
    font-weight: 500;
    z-index: 3;
    letter-spacing: 1px;
    text-shadow: 0 2px 5px rgba(0,0,0,0.8);
}

.solution-content {
    flex: 1;
}

.solution-content p {
    margin-bottom: 30px;
}

.curriculum-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.curriculum-list li {
    display: flex;
    gap: 20px;
    align-items: flex-start;
    background: var(--bg-light);
    padding: 20px;
    border-radius: 15px;
}

.curriculum-list p {
    margin-bottom: 0;
    font-size: 0.95rem;
}

.day-badge {
    background: var(--primary);
    color: white;
    padding: 5px 12px;
    border-radius: 8px;
    font-weight: 600;
    font-size: 0.9rem;
    white-space: nowrap;
}

/* Pricing Base on Screen 5 */
.pricing-section {
    padding: 100px 0;
    background: var(--gradient-purple);
    color: white;
}

.pricing-layout {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.pricing-text {
    max-width: 600px;
    margin-bottom: 50px;
}

.pricing-text h2 {
    color: white;
}

.pricing-text p {
    color: rgba(255,255,255,0.9);
}

.price-box {
    margin: 30px 0;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 20px;
}

.price-old {
    font-size: 1.5rem;
    text-decoration: line-through;
    color: rgba(255,255,255,0.6);
}

.price-new {
    font-size: 4rem;
    font-weight: 700;
    line-height: 1;
}

/* Form Card */
.form-card {
    background: white;
    padding: 40px;
    border-radius: 24px;
    width: 100%;
    max-width: 500px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.2);
    color: var(--text-main);
    text-align: left;
}

.form-card h3 {
    text-align: center;
    margin-bottom: 30px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    font-size: 0.95rem;
}

.form-group input {
    width: 100%;
    padding: 15px;
    border: 1px solid #e1e1e1;
    border-radius: 12px;
    font-family: inherit;
    font-size: 1rem;
    outline: none;
    transition: border-color 0.3s;
}

.form-group input:focus {
    border-color: var(--primary);
}

/* Loader */
.loader {
    border: 3px solid #f3f3f3;
    border-radius: 50%;
    border-top: 3px solid var(--primary);
    width: 24px;
    height: 24px;
    animation: spin 1s linear infinite;
    margin: 15px auto;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.success-message {
    background: #e8f5e9;
    color: #2e7d32;
    padding: 15px;
    border-radius: 12px;
    margin-top: 20px;
    text-align: center;
    font-size: 0.95rem;
    font-weight: 500;
}

/* Footer */
footer {
    background: #111;
    color: #888;
    text-align: center;
    padding: 40px 0;
}

footer p {
    font-size: 0.9rem;
    margin-bottom: 5px;
    color: #888;
}

/* Responsive Design */
@media (max-width: 768px) {
    h1 { font-size: 2.5rem; }
    h2 { font-size: 2rem; }
    
    .hero-stats {
        flex-direction: column;
        gap: 30px;
    }
    
    .solution-layout {
        flex-direction: column;
    }

    .form-card {
        padding: 30px 20px;
    }
}

/* Payment & QR Section */
.payment-section {
    text-align: center;
    animation: fadeIn 0.5s;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.success-alert {
    background: #e8f5e9;
    color: #2e7d32;
    padding: 15px;
    border-radius: 12px;
    margin-bottom: 20px;
    font-size: 1.1rem;
    font-weight: 600;
}

.payment-desc {
    font-size: 0.95rem;
    margin-bottom: 20px;
}

.qr-box {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 16px;
    margin-bottom: 20px;
    border: 2px dashed #e1e1e1;
}

.qr-image {
    max-width: 100%;
    height: auto;
    border-radius: 10px;
}

.bank-details {
    background: #fdfbf7;
    padding: 15px;
    border-radius: 12px;
    text-align: left;
    margin-bottom: 20px;
    font-size: 0.95rem;
    border: 1px solid #f1f1f1;
}

.bank-details p {
    margin-bottom: 5px;
}

.bank-details p:last-child {
    margin-bottom: 0;
}

.transfer-note {
    margin-top: 15px;
    padding-top: 15px;
    border-top: 1px solid #eaeaea;
}

.note-title {
    color: #d32f2f;
    font-weight: 700;
    margin-bottom: 8px !important;
    font-size: 0.9rem;
}

.transfer-note ul {
    list-style: none;
    margin: 10px 0;
    padding: 12px;
    background: #f1f3f5;
    border-radius: 8px;
    color: #1e293b;
}

.transfer-note ul li {
    margin-bottom: 5px;
    font-size: 1.05rem;
}

.transfer-note small {
    color: #64748b;
    font-size: 0.85rem;
}