:root {
    --kh-primary: #006067;
    --kh-primary-hover: #004d53;
    --kh-primary-soft: #e7f5f5;
    --kh-text: #122025;
    --kh-text-light: #5f6b72;
    --kh-border: #e5ecec;
    --kh-bg: #f5f8f8;
    --kh-white: #ffffff;
    --kh-orange: #ff7a1a;
    --kh-danger: #ef4444;
    --kh-success: #16a34a;
    --kh-shadow: 0 16px 40px rgba(0, 96, 103, 0.08);
    --kh-radius-lg: 24px;
    --kh-radius-md: 18px;
    --kh-radius-sm: 14px;
    --kh-container: 1280px;
}

.kh-page,
.kh-page * {
    box-sizing: border-box;
}

.kh-page {
    background: linear-gradient(180deg, #f7fbfb 0%, #f4f8f8 100%);
    color: var(--kh-text);
    font-size: 16px;
    line-height: 1.65;
}

.kh-container {
    width: min(var(--kh-container), calc(100% - 32px));
    margin: 0 auto;
}

.kh-section {
    padding: 48px 0;
}

/* =========================
   BUTTONS
========================= */
.kh-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: 10px 24px;
    border: 0;
    border-radius: 14px;
    text-decoration: none;
    font-size: 15px;
    font-weight: 800;
    cursor: pointer;
    transition: all 0.25s ease;
}

.kh-btn--primary {
    color: #fff;
    background: linear-gradient(135deg, var(--kh-primary), #0b7e86);
    box-shadow: 0 14px 28px rgba(0, 96, 103, 0.18);
}

.kh-btn--primary:hover {
    background: linear-gradient(135deg, var(--kh-primary-hover), var(--kh-primary));
    transform: translateY(-1px);
    color: #fff;
}

.kh-btn--outline {
    color: var(--kh-primary);
    background: #fff;
    border: 1px solid rgba(0, 96, 103, 0.18);
}

.kh-btn--outline:hover {
    background: var(--kh-primary-soft);
}

/* =========================
   CARD
========================= */
.kh-card {
    background: var(--kh-white);
    border: 1px solid var(--kh-border);
    border-radius: var(--kh-radius-lg);
    box-shadow: var(--kh-shadow);
}

.kh-card--padded {
    padding: 28px;
}

/* =========================
   COURSE DETAIL HERO
========================= */
.kh-course-hero {
    padding: 40px 0 28px;
}

.kh-course-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 390px;
    gap: 28px;
    align-items: start;
}

.kh-course-main {
    min-width: 0;
    order: 1;
}

.kh-course-sidebar {
    min-width: 0;
    order: 2;
    position: sticky;
    top: 100px;
}

.kh-breadcrumb {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 14px;
    font-size: 14px;
    color: var(--kh-text-light);
}

.kh-breadcrumb a {
    color: var(--kh-primary);
    text-decoration: none;
}

.kh-breadcrumb a:hover {
    text-decoration: underline;
}

.kh-course-head {
    background: linear-gradient(135deg, #032f33 0%, #006067 100%);
    color: #fff;
    border-radius: 28px;
    padding: 34px;
    overflow: hidden;
    position: relative;
}

.kh-course-head::before {
    content: "";
    position: absolute;
    inset: auto -40px -80px auto;
    width: 220px;
    height: 220px;
    border-radius: 50%;
    background: rgba(255,255,255,0.06);
}

.kh-course-category {
    display: inline-flex;
    align-items: center;
    min-height: 36px;
    padding: 8px 14px;
    border-radius: 999px;
    background: rgba(255,255,255,0.12);
    color: #fff;
    font-size: 13px;
    font-weight: 700;
    margin-bottom: 14px;
}

.kh-course-title {
    margin: 0 0 12px;
    font-size: 35px;
    line-height: 1.18;
    font-weight: 900;
    letter-spacing: -0.02em;
}

.kh-course-subtitle {
    margin: 0 0 18px;
    font-size: 18px;
    color: rgba(255,255,255,0.86);
    max-width: 820px;
}

.kh-course-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 16px 20px;
    align-items: center;
}

.kh-course-teacher-mini {
    display: inline-flex;
    align-items: center;
    gap: 12px;
}

.kh-course-teacher-mini img {
    width: 42px;
    height: 42px;
    border-radius: 50%;
    object-fit: cover;
    border: 2px solid rgba(255,255,255,0.2);
}

.kh-course-teacher-mini span,
.kh-course-meta-item {
    font-size: 15px;
    font-weight: 700;
    color: #fff;
}

/* =========================
   SIDEBAR COURSE BOX
========================= */
.kh-course-buybox {
    position: sticky;
    top: 24px;
    overflow: hidden;
}

.kh-course-media {
    position: relative;
    display: block;
    aspect-ratio: 16 / 9;
    background: #dfe8e8;
    overflow: hidden;
    text-decoration: none;
}

.kh-course-media img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
    transition: transform 0.35s ease;
}

.kh-course-media:hover img {
    transform: scale(1.04);
}

.kh-course-play {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    pointer-events: none;
}

.kh-course-play span {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: rgba(255,255,255,0.9);
    box-shadow: 0 12px 30px rgba(0,0,0,0.18);
    position: relative;
}

.kh-course-play span::before {
    content: "";
    position: absolute;
    left: 24px;
    top: 16px;
    border-left: 22px solid var(--kh-primary);
    border-top: 14px solid transparent;
    border-bottom: 14px solid transparent;
}

.kh-course-buycontent {
    padding: 24px;
}

.kh-course-price {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 10px 14px;
    margin-bottom: 10px;
}

.kh-course-price-new {
    font-size: 30px;
    line-height: 1;
    font-weight: 900;
    color: var(--kh-primary);
}

.kh-course-price-old {
    font-size: 18px;
    color: #97a3a8;
    text-decoration: line-through;
    font-weight: 700;
}

.kh-course-price-note {
    display: flex;
    align-items: center;
    gap: 8px;
    color: #ff6a2b;
    font-size: 14px;
    font-weight: 700;
    margin-bottom: 20px;
}

.kh-course-actions {
    display: grid;
    gap: 12px;
    margin-bottom: 22px;
}

.kh-course-features {
    display: grid;
    gap: 12px;
    padding-top: 18px;
    border-top: 1px solid var(--kh-border);
}

.kh-course-feature {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    color: var(--kh-text-light);
    font-size: 15px;
}

.kh-course-feature i {
    width: 18px;
    color: var(--kh-primary);
    margin-top: 3px;
}

/* =========================
   CONTENT BLOCKS
========================= */
.kh-stack {
    display: grid;
    gap: 22px;
    margin-top: 28px;
}

.kh-block-title {
    margin: 0 0 18px;
    font-size: 32px;
    line-height: 1.2;
    font-weight: 900;
    color: var(--kh-text);
    letter-spacing: -0.02em;
}

.kh-content {
    color: #344249;
    font-size: 17px;
}

.kh-content p {
    margin: 0 0 14px;
}

.kh-content p:last-child {
    margin-bottom: 0;
}

.kh-course-highlight-list {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px 22px;
}

.kh-course-highlight {
    display: flex;
    gap: 12px;
    align-items: flex-start;
    font-size: 17px;
    color: #33424a;
}

.kh-course-highlight i {
    width: 22px;
    color: #0ea35a;
    margin-top: 3px;
}

/* =========================
   TEACHER BOX
========================= */
.kh-teacher-box {
    display: grid;
    grid-template-columns: 120px minmax(0, 1fr);
    gap: 22px;
    align-items: start;
}

.kh-teacher-avatar img {
    width: 120px;
    height: 120px;
    border-radius: 24px;
    object-fit: cover;
    display: block;
    border: 1px solid var(--kh-border);
}

.kh-teacher-name {
    margin: 0 0 10px;
    font-size: 26px;
    line-height: 1.2;
    font-weight: 900;
    color: var(--kh-text);
}

.kh-teacher-desc {
    color: #4a5961;
    font-size: 16px;
}

.kh-teacher-desc p {
    margin: 0 0 12px;
}

/* =========================
   COURSE LIST PAGE
========================= */
.kh-list-hero {
    padding: 42px 0 22px;
}

.kh-list-head {
    display: flex;
    justify-content: space-between;
    align-items: end;
    gap: 20px;
    margin-bottom: 22px;
}

.kh-list-title {
    margin: 0 0 8px;
    font-size: 40px;
    line-height: 1.15;
    font-weight: 900;
    color: var(--kh-text);
}

.kh-list-desc {
    margin: 0;
    color: var(--kh-text-light);
    font-size: 17px;
}

.kh-list-filter {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.kh-chip {
    display: inline-flex;
    align-items: center;
    min-height: 40px;
    padding: 8px 14px;
    border-radius: 999px;
    background: #fff;
    border: 1px solid var(--kh-border);
    color: var(--kh-text-light);
    text-decoration: none;
    font-size: 14px;
    font-weight: 700;
    transition: all 0.25s ease;
}

.kh-chip:hover,
.kh-chip.is-active {
    color: var(--kh-primary);
    border-color: rgba(0, 96, 103, 0.2);
    background: var(--kh-primary-soft);
}

.kh-course-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 22px;
}

.kh-course-card {
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.kh-course-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 45px rgba(0, 96, 103, 0.14);
}

.kh-course-card__thumb {
    position: relative;
    display: block;
    aspect-ratio: 16 / 10;
    overflow: hidden;
    background: #dbe5e5;
}

.kh-course-card__thumb img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
    transition: transform 0.35s ease;
}

.kh-course-card:hover .kh-course-card__thumb img {
    transform: scale(1.04);
}

.kh-course-card__body {
    padding: 20px;
    display: grid;
    gap: 14px;
}

.kh-course-card__title {
    margin: 0;
    font-size: 20px;
    line-height: 1.4;
    font-weight: 900;
}

.kh-course-card__title a {
    color: var(--kh-text);
    text-decoration: none;
}

.kh-course-card__title a:hover {
    color: var(--kh-primary);
}

.kh-course-card__teacher {
    display: flex;
    align-items: center;
    gap: 12px;
}

.kh-course-card__teacher img {
    width: 42px;
    height: 42px;
    border-radius: 50%;
    object-fit: cover;
}

.kh-course-card__teacher span {
    color: var(--kh-text-light);
    font-size: 14px;
    font-weight: 700;
}

.kh-course-card__excerpt {
    color: #546169;
    font-size: 15px;
}

.kh-course-card__bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
}

.kh-course-card__price {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.kh-course-card__price-new {
    color: var(--kh-primary);
    font-size: 24px;
    line-height: 1;
    font-weight: 900;
}

.kh-course-card__price-old {
    color: #a0acb1;
    font-size: 14px;
    text-decoration: line-through;
    font-weight: 700;
}

.kh-course-card__link {
    min-width: 128px;
}

/* =========================
   RESPONSIVE
========================= */
@media (max-width: 1199px) {
    .kh-course-layout {
        grid-template-columns: minmax(0, 1fr) 360px;
    }

    .kh-course-title {
        font-size: 30px;
    }

    .kh-course-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 991px) {
    .kh-course-layout {
        grid-template-columns: 1fr;
    }

    .kh-course-main {
        order: 2;
    }

    .kh-course-sidebar {
        order: 1;
        position: static;
    }

    .kh-course-buybox {
        position: relative;
        top: auto;
    }

    .kh-course-highlight-list {
        grid-template-columns: 1fr;
    }

    .kh-teacher-box {
        grid-template-columns: 1fr;
    }

    .kh-course-title {
        font-size: 28px;
    }

    .kh-list-head {
        flex-direction: column;
        align-items: flex-start;
    }
}

@media (max-width: 767px) {
    .kh-container {
        width: min(100%, calc(100% - 20px));
    }

    .kh-section,
    .kh-course-hero,
    .kh-list-hero {
        padding: 22px 0;
    }

    .kh-card--padded,
    .kh-course-buycontent {
        padding: 18px;
    }

    .kh-course-head {
        padding: 22px 18px;
        border-radius: 22px;
    }

    .kh-course-title,
    .kh-list-title,
    .kh-block-title {
        font-size: 28px;
    }

    .kh-course-subtitle,
    .kh-content,
    .kh-course-highlight,
    .kh-list-desc {
        font-size: 16px;
    }

    .kh-course-price-new {
        font-size: 36px;
    }

    .kh-course-grid {
        grid-template-columns: 1fr;
    }

    .kh-btn {
        width: 100%;
    }
}


.product-topbar {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    gap: 20px;
    margin-bottom: 28px;
    padding-bottom: 18px;
    border-bottom: 1px solid #e7edf0;
}

.product-topbar__left {
    flex: 1;
    min-width: 0;
}

.product-topbar__title {
    position: relative;
    margin: 0;
    padding-left: 18px;
    font-size: 30px;
    font-weight: 800;
    line-height: 1.2;
    color: #111827;
    letter-spacing: -0.4px;
}

.product-topbar__title::before {
    content: "";
    position: absolute;
    left: 0;
    top: 4px;
    width: 6px;
    height: calc(100% - 8px);
    border-radius: 999px;
    background: linear-gradient(180deg, #006067 0%, #00a0ad 100%);
}

.product-topbar__right {
    flex-shrink: 0;
}

.product-topbar__form {
    display: flex;
    align-items: center;
    gap: 12px;
    margin: 0;
}

.product-topbar__label {
    margin: 0;
    font-size: 13px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: #6b7280;
    white-space: nowrap;
}

.product-topbar__control {
    position: relative;
    min-width: 220px;
}

.product-topbar__control::after {
    content: "";
    position: absolute;
    top: 50%;
    right: 16px;
    width: 8px;
    height: 8px;
    margin-top: -6px;
    border-right: 2px solid #006067;
    border-bottom: 2px solid #006067;
    transform: rotate(45deg);
    pointer-events: none;
}

.product-topbar__select {
    width: 100%;
    height: 46px;
    padding: 0 42px 0 16px;
    border: 1px solid #d9e3e8;
    border-radius: 12px;
    background: #fff;
    font-size: 14px;
    font-weight: 600;
    color: #1f2937;
    outline: none;
    cursor: pointer;
    appearance: none;
    -webkit-appearance: none;
    -moz-appearance: none;
    transition: all 0.25s ease;
}

.product-topbar__select:hover {
    border-color: #b9c9d0;
    box-shadow: 0 10px 24px rgba(0, 0, 0, 0.05);
}

.product-topbar__select:focus {
    border-color: #006067;
    box-shadow: 0 0 0 4px rgba(0, 96, 103, 0.12);
}

@media (max-width: 768px) {
    .product-topbar {
        flex-direction: column;
        align-items: stretch;
        gap: 14px;
    }

    .product-topbar__title {
        font-size: 24px;
        padding-left: 14px;
    }

    .product-topbar__form {
        flex-direction: column;
        align-items: stretch;
        gap: 8px;
    }

    .product-topbar__control {
        width: 100%;
        min-width: 100%;
    }

    .product-topbar__label {
        font-size: 12px;
    }
}