:root {
    --primary-green: #1DB954;
    --dark-green: #1E8449;
    --light-green-bg: #E8F5E9;
    --dark-text: #222;
    --body-text: #555;
    --white-bg: #FFFFFF;
    --section-bg: #F9FAFB;
    --border-color: #E7E7E7;
}
/* ===============================
   HERO SECTION
=============================== */
.hero-section {
    position: relative;
    overflow: hidden;
    color: white;
    background: radial-gradient(circle at top, #0a0e27, #050617 70%);
}

.hero-video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover; /* đảm bảo video che kín */
    z-index: 0;
}

.hero-overlay {
    position: absolute;
    height: 100%;
    top: 0;
    background: linear-gradient(to bottom, rgba(10,14,39,0.4), rgba(5,6,23,0.9));
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    padding-top: 200px;
    text-align: center;
}

.hero-title {
    font-size: 44px;
    font-weight: 800;
    color: #6ef5e9;
    margin-bottom: 20px;
}

.hero-subtitle {
    font-size: 18px;
    opacity: 0.9;
    max-width: 700px;
    margin: 0 auto 40px;
    line-height: 1.6;
}

.hero-buttons {
    display: flex;
    justify-content: center;
    gap: 20px;
}

.btn {
    padding: 12px 28px;
    border-radius: 8px;
    font-weight: 600;
    text-decoration: none;
    transition: 0.3s;
    display: flex;
}

.btn-gradient {
    background: linear-gradient(90deg, #00ffcc, #3a8eff);
    color: #0a0e27;
}

.btn-outline {
    border: 2px solid #3a8eff;
    color: #3a8eff;
}

.btn-gradient:hover {
    transform: translateY(-3px);
    box-shadow: 0 0 12px #3a8eff;
}

.btn-outline:hover {
    background: #3a8eff;
    color: #fff;
}
/* ===============================
   ABOUT SECTION
=============================== */
.about {
    padding: 100px 0;
    background: #fff;
}

    .about .container {
        display: grid;
        grid-template-columns: 0.6fr 1fr;
        gap: 30px;
    }

.about-right h2 {
    display: flex;
    justify-content: center;
    align-items: center;
}

.about-intro-content {
    position: relative;
    padding-left: 20px;
    border-left: 4px solid #1DB954;
}

.about h2 {
    color: var(--dark-green);
    font-size: 50px;
    margin-bottom: 16px;
    font-weight: bold;
}

.about p {
    margin-bottom: 20px;
    line-height: 1.7;
    color: #444;
    font-size: 20px;
}

.about img {
    width: 100%;
    border-radius: 12px;
    height: auto;
    border: 1px solid #1DB954;
}

.about-feature-area h3 {
    font-size: 2.0rem;
    font-weight: 600;
    color: var(--dark-text);
    margin-bottom: 30px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: center;
    align-items: center;
}

.about-feature-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
}

.about-feature-card {
    background: var(--white-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 25px;
    display: flex;
    align-items: flex-start;
    gap: 20px;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

    .about-feature-card:hover {
        transform: translateY(-5px);
        box-shadow: 0 12px 30px rgba(29, 185, 84, 0.15);
        border-color: transparent;
    }

    .about-feature-card::before {
        content: "";
        position: absolute;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        border-radius: 12px;
        border: 2px solid transparent;
        background: linear-gradient(135deg, var(--primary-green), var(--dark-green)) border-box;
        -webkit-mask: linear-gradient(#fff 0 0) padding-box, linear-gradient(#fff 0 0);
        -webkit-mask-composite: destination-out;
        mask-composite: exclude;
        opacity: 0;
        transition: opacity 0.3s ease;
    }

    .about-feature-card:hover::before {
        opacity: 1;
    }

.about-feature-icon {
    font-size: 2rem;
    color: var(--dark-green);
    background-color: var(--light-green-bg);
    border-radius: 8px;
    width: 55px;
    height: 55px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}


.about-card-content h4 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--dark-text);
    margin-top: 0;
    margin-bottom: 8px;
}

.about-card-content p {
    font-size: 0.95rem;
    color: var(--body-text);
    margin: 0;
    line-height: 1.5;
}

.benefits {
    display: flex;
    gap: 20px;
    margin-top: 20px;
}

.benefit {
    background: #f1f4fb;
    padding: 20px;
    border-radius: 10px;
    flex: 1;
    text-align: center;
    font-weight: 500;
}
/* ===============================
   MODULES SECTION
=============================== */
.modules-section {
    padding: 100px 0;
    background: #f8f9fc;
    text-align: center;
}

/* Modules */
.modules-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
    margin-top: 20px;
}

.module-card {
    position: relative;
    border-radius: 20px;
    background: #fff;
    border: 1px solid rgba(148, 163, 184, 0.15);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.08);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    overflow: hidden;
    height: 100%;
    display: flex;
    flex-direction: column;
}

    .module-card:hover .module-content {
        transform: translateY(0);
        box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
    }

.module-image {
    height: 400px;
    overflow: hidden;
}

    .module-image img {
        width: 100%;
        height: 100%;
        object-fit: cover;
        transition: transform 0.4s ease;
    }

.module-card:hover .module-image img {
    transform: scale(1.1);
}

.module-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(0, 0, 0, 0.1), rgba(0, 0, 0, 0.3));
    opacity: 0;
    transition: opacity 0.3s ease;
}

.module-card:hover .module-overlay {
    opacity: 1;
}

.module-content {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    padding: 1.5rem;
    color: #fff;
    background: linear-gradient(to top, rgba(0,0,0,0.9), transparent);
}

.module-icon {
    width: 64px;
    height: 64px;
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 16px;
    transition: all 0.3s ease;
    position: relative;
    z-index: 2;
}

.module-school .module-icon {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    box-shadow: 0 8px 20px rgba(102, 126, 234, 0.3);
}

.module-ebook .module-icon {
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    box-shadow: 0 8px 20px rgba(240, 147, 251, 0.3);
}

.module-standard .module-icon {
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    box-shadow: 0 8px 20px rgba(79, 172, 254, 0.3);
}

.module-icon i {
    font-size: 1.5rem;
    color: #fff;
}

.module-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 12px;
    color: #fff;
    text-align: center;
    line-height: 1.3;
}

.module-description {
    color: var(--text-medium);
    margin-bottom: 20px;
    text-align: center;
    line-height: 1.6;
    flex: 1;
}

.module-features {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    justify-content: center;
    margin-top: auto;
}

.feature-tag {
    background: rgba(37, 99, 235, 0.1);
    color: var(--primary);
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
    border: 1px solid rgba(37, 99, 235, 0.2);
    transition: all 0.3s ease;
}

.module-school .feature-tag {
    background: rgba(102, 126, 234, 0.1);
    color: #667eea;
    border-color: rgba(102, 126, 234, 0.2);
}

.module-ebook .feature-tag {
    background: rgba(240, 147, 251, 0.1);
    color: #f093fb;
    border-color: rgba(240, 147, 251, 0.2);
}

.module-standard .feature-tag {
    background: rgba(79, 172, 254, 0.1);
    color: #4facfe;
    border-color: rgba(79, 172, 254, 0.2);
}

.module-card:hover .feature-tag {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

/* Module specific hover effects */
.module-school:hover {
    border-color: rgba(102, 126, 234, 0.3);
}

.module-ebook:hover {
    border-color: rgba(240, 147, 251, 0.3);
}

.module-standard:hover {
    border-color: rgba(79, 172, 254, 0.3);
}

.tag {
    display: inline-block;
    background: #e6f0ff;
    color: #0066cc;
    padding: 5px 10px;
    border-radius: 20px;
    font-size: 13px;
    margin: 5px;
}
/* Phan-he section styling */
#phan-he {
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
    position: relative;
    overflow: hidden;
}

    #phan-he::before {
        content: "";
        position: absolute;
        top: -50%;
        left: -50%;
        width: 200%;
        height: 200%;
        background: radial-gradient( circle, rgba(37, 99, 235, 0.03) 0%, transparent 70% );
        animation: float 20s ease-in-out infinite;
        pointer-events: none;
    }
/* ===============================
   QUY TRÌNH
=============================== */
.process-section {
    padding: 100px 0;
    text-align: center;
}

.section-header {
    margin-bottom: 50px;
}

.section-title {
    font-size: 32px;
    color: #0a0e27;
}

.steps-container {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.steps-row {
    display: flex;
    justify-content: center;
    gap: 25px;
    flex-wrap: wrap;
}

.step-card {
    color: #fff;
    padding: 30px;
    border-radius: 14px;
    width: 220px;
    transition: 0.3s;
}

    .step-card:hover {
        transform: translateY(-5px);
        box-shadow: 0 0 12px rgba(0,255,170,0.5);
    }

    .step-card .icon {
        font-size: 28px;
        margin-bottom: 10px;
    }

    .step-card h3 {
        margin-bottom: 10px;
    }

.color1 {
    background: #aaf0c4;
}

.color2 {
    background: #f8a256;
}

.color3 {
    background: #4c64f1;
}

.color4 {
    background: #b687e1;
}

.color5 {
    background: #f08fce;
}

.color6 {
    background: #c8de79;
}

.color7 {
    background: #f8989e;
}

.number {
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    margin: 10px auto;
    font-size: 18px;
    white-space: nowrap;
}

.color1 .number,
.color1 .icon {
    color: #2196f3;
}

.color2 .number,
.color2 .icon {
    color: #4caf50;
}

.color3 .number,
.color3 .icon {
    color: #ff9800;
}

.color4 .number,
.color4 .icon {
    color: #9c27b0;
}

.color5 .number,
.color5 .icon {
    color: #e91e63;
}

.color6 .number,
.color6 .icon {
    color: #00bcd4;
}

.color7 .number,
.color7 .icon {
    color: #795548;
}

#quy-trinh p {
    color: #0a0000;
    margin-bottom: 40px;
    font-style: italic;
}

.users-section {
    padding: 100px 0;
    background: #fff;
    text-align: center;
}

/* Users */
.users-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 28px;
    margin-top: 20px;
}

.user-card {
    position: relative;
    border-radius: 20px;
    background: #fff;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.08);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    overflow: hidden;
    height: 100%;
    display: flex;
    flex-direction: column;
    border: 1px solid rgba(148, 163, 184, 0.15);
}

    .user-card:hover {
        transform: translateY(-8px) scale(1.02);
        box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
    }

.user-avatar {
    position: relative;
    height: 200px;
    overflow: hidden;
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
}

    .user-avatar img {
        width: 100%;
        height: 100%;
        object-fit: cover;
        transition: transform 0.4s ease;
    }

.user-card:hover .user-avatar img {
    transform: scale(1.1);
}

.user-info h3 {
    margin-bottom: 8px;
    font-weight: 600;
    color: #0a0e27;
}

#nguoi-dung {
    background: linear-gradient(135deg, #f1f5f9 0%, #e2e8f0 100%);
    position: relative;
    overflow: hidden;
}
/* ===============================
   CTA SECTION
=============================== */
.cta-section {
    background: linear-gradient(90deg, #055726, #055726);
    color: white;
    text-align: center;
    padding: 100px 20px;
}

.cta-title {
    font-size: 32px;
    margin-bottom: 20px;
}

.cta-subtitle {
    font-size: 18px;
    margin-bottom: 40px;
    opacity: 0.9;
}

.btn-light {
    background: #fff;
    color: #0a0e27;
    padding: 14px 30px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: 0.3s;
    width: 20%;
    margin: 20px auto 0;
    text-align: center;
}

    .btn-light:hover {
        background: #3a8eff;
        color: white;
    }
.brand-logo{
    width: 40%;
}
@media (max-width: 768px) {
    .about .container {
        grid-template-columns: 1fr 1fr;
        display: block;
    }
    .about-feature-grid {
        display: block;
        
    }
    .modules-grid {
        grid-template-columns: repeat(1, 1fr);
    }
    .users-grid {
        grid-template-columns: repeat(1, 1fr);
    }
    .scale-font-size{
        font-size: 30px !important;
    }
    .mobile-header .site-brand {
         padding: 0px 0 0px 0; 
    }

    .mobile-header img {
        max-width: 100%;
        height: auto;
    }

}