html {
    font-size: 16px;
}

body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    background: #f8fafc;
    color: #1e293b;
}


/* =========================
   NAVBAR
   ========================= */

.navbar {
    min-height: 70px;
}

.navbar-brand {
    font-size: 24px;
}

.nav-link {
    font-weight: 500;
    transition: 0.2s;
}

    .nav-link:hover {
        color: #0d6efd !important;
    }


/* =========================
   HERO
   ========================= */

.hero-section {
    padding: 100px 0;
    background: linear-gradient( 135deg, #f8fafc, #e0ecff );
}

.hero-box {
    min-height: 400px;
    border-radius: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient( 135deg, #0d6efd, #6f42c1 );
    box-shadow: 0 20px 50px rgba(13, 110, 253, 0.25);
}

.hero-icon {
    font-size: 100px;
    margin-bottom: 20px;
}


/* =========================
   FEATURE
   ========================= */

.feature-card {
    padding: 35px 25px;
    border-radius: 20px;
    background: #f8fafc;
    transition: 0.3s;
}

    .feature-card:hover {
        transform: translateY(-5px);
        box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
    }

.feature-icon {
    font-size: 45px;
    margin-bottom: 15px;
}


/* =========================
   PRODUCT
   ========================= */

.product-card {
    border-radius: 18px;
    overflow: hidden;
    transition: all 0.3s ease;
}

    .product-card:hover {
        transform: translateY(-8px);
        box-shadow: 0 15px 35px rgba(0, 0, 0, 0.12) !important;
    }

.product-image {
    width: 100%;
    height: 240px;
    object-fit: cover;
}

.price {
    color: #0d6efd;
    font-size: 20px;
    font-weight: 700;
}


/* =========================
   DETAIL
   ========================= */

.detail-card {
    border-radius: 25px;
}

.detail-image {
    width: 100%;
    height: 100%;
    min-height: 450px;
    object-fit: cover;
}


/* =========================
   BUTTON
   ========================= */

.btn {
    border-radius: 10px;
    font-weight: 600;
}


/* =========================
   FOOTER
   ========================= */

.footer {
    margin-top: 80px;
    padding: 45px 0;
    background: #111827;
    color: white;
}


/* =========================
   MOBILE
   ========================= */

@media (max-width: 768px) {

    .hero-section {
        padding: 60px 0;
    }

    .hero-box {
        min-height: 300px;
    }

    .hero-icon {
        font-size: 70px;
    }

    .detail-image {
        min-height: 300px;
    }
}

/* ============================= */
/* WEBSITE HỌC TẬP */
/* ============================= */

body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    background: #f5f7fb;
    color: #1f2937;
}


/* Trang chính */

.learning-page {
    min-height: 100vh;
    background: linear-gradient(135deg, #f8fbff, #eef4ff);
}


/* Tiêu đề */

.hero {
    text-align: center;
    padding: 70px 20px 55px;
}

.hero-icon {
    font-size: 55px;
    margin-bottom: 15px;
}

.hero h1 {
    font-size: 48px;
    font-weight: 800;
    letter-spacing: 1px;
    margin-bottom: 12px;
    color: #172554;
}

.hero p {
    font-size: 21px;
    margin-bottom: 8px;
    color: #334155;
}

.hero span {
    color: #64748b;
    font-size: 16px;
}


/* Tiêu đề danh sách */

.section-title {
    text-align: center;
    margin-bottom: 35px;
}

    .section-title h2 {
        font-weight: 700;
        color: #172554;
    }

    .section-title p {
        color: #64748b;
    }


/* Card */

.week-card {
    position: relative;
    background: white;
    border-radius: 18px;
    padding: 30px;
    min-height: 280px;
    border: 1px solid #e2e8f0;
    box-shadow: 0 8px 25px rgba(15, 23, 42, 0.07);
    transition: all 0.25s ease;
    overflow: hidden;
}


    /* Hiệu ứng khi rê chuột */

    .week-card:hover {
        transform: translateY(-7px);
        box-shadow: 0 15px 35px rgba(15, 23, 42, 0.13);
    }


/* Số tuần */

.week-number {
    position: absolute;
    top: 18px;
    right: 22px;
    font-size: 14px;
    font-weight: bold;
    color: #94a3b8;
}


/* Icon */

.week-icon {
    font-size: 42px;
    margin-bottom: 18px;
}


/* Tiêu đề tuần */

.week-card h3 {
    font-size: 27px;
    font-weight: 700;
    margin-bottom: 12px;
    color: #1e293b;
}


/* Nội dung */

.week-card p {
    color: #64748b;
    line-height: 1.6;
    min-height: 52px;
}


/* Tuần đang có bài */

.week-card.active {
    border: 2px solid #2563eb;
    box-shadow: 0 10px 30px rgba(37, 99, 235, 0.15);
}


    /* Chữ đang học */

    .week-card.active h3 {
        color: #2563eb;
    }


/* Nút xem bài */

.btn-start {
    display: inline-block;
    margin-top: 15px;
    padding: 11px 20px;
    background: #2563eb;
    color: white;
    text-decoration: none;
    border-radius: 10px;
    font-weight: 600;
    transition: 0.2s;
}


    .btn-start:hover {
        background: #1d4ed8;
        color: white;
        transform: translateX(3px);
    }


/* Nút chưa có bài */

.btn-disabled {
    margin-top: 15px;
    padding: 10px 18px;
    border: none;
    border-radius: 10px;
    background: #e2e8f0;
    color: #94a3b8;
    font-weight: 600;
}


/* Footer */

.learning-footer {
    text-align: center;
    margin-top: 70px;
    padding: 30px 20px;
    color: #64748b;
    border-top: 1px solid #e2e8f0;
}


    .learning-footer p {
        margin-bottom: 5px;
    }