.section {
    padding: 56px 0;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 16px;
}

.centered {
    text-align: center;
    margin-bottom: 28px;
}

.h2 {
    font-size: 28px;
    letter-spacing: .06em;
    font-weight: 800;
    color: var(--brand);
    text-transform: uppercase
}

/* сетки */
.grid-2 {
    display: flex;
    gap: 32px;
    align-items: start;
    justify-content: center;
}

.grid-reverse {
    grid-template-columns: 1fr 0.8fr
}

.stack>*+* {
    margin-top: 16px
}

/* списки */
.bullet-list {
    line-height: 1.6;
    margin-left: 18px
}

.bullet-list li {
    margin: 8px 0
}

.num-list {
    line-height: 1.7;
    padding-left: 22px
}

.num-list li {
    margin: 6px 0
}

/* плейсхолдеры */
.placeholder {
    position: relative;
    width: 100%;
    background: repeating-linear-gradient(135deg, #f0f0f0 0 12px, #e6e6e6 12px 24px);
    border: 1px solid #ddd;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #7a7a7a;
    font-weight: 700;
    letter-spacing: .08em;
    user-select: none;
}

.placeholder span {
    opacity: .75
}

.img-3d {
    aspect-ratio: 4/3
}

.img-scheme {
    aspect-ratio: 1/1
}

.video {
    aspect-ratio: 16/9
}

.book {
    aspect-ratio: 3/4;
    max-width: 320px;
    margin: 0 auto
}

/* подписи-ярлыки справа от 3D */
.tag-row {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 14px
}

.tag {
    font-size: 12px;
    border: 1px solid #ddd;
    border-radius: 999px;
    padding: 6px 10px;
    color: #555;
    background: #fafafa
}

/* секция загрузки */
.download-section {
    background: var(--dark);
    color: #fff;
    padding: 60px 0
}

.download-title {
    font-size: 18px;
    font-weight: 700;
    margin: 0 0 20px
}

.download-form {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    align-items: end
}

.download-form .wide {
    grid-column: 1/-1
}

.download-form input {
    width: 100%;
    height: 44px;
    border: 1px solid rgba(255, 255, 255, .25);
    border-radius: 6px;
    background: rgba(255, 255, 255, .06);
    color: #fff;
    padding: 0 14px;
}

.download-form input::placeholder {
    color: rgba(255, 255, 255, .7)
}

.btn {
    grid-column: 2/-1;
    justify-self: end;
    cursor: pointer;
    height: 44px;
    padding: 0 22px;
    border-radius: 8px;
    border: 0;
    background: #d6a46a;
    color: #222;
    font-weight: 700;
    transition: transform .15s ease, filter .15s ease;
}

.btn:hover {
    transform: translateY(-2px);
    filter: brightness(1.05)
}

.book-side {
    display: flex;
    align-items: flex-end;
    justify-content: center
}

/* a11y */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0
}

/* адаптив */
@media (max-width: 960px) {

    .grid-2,
    .grid-reverse {
        grid-template-columns: 1fr
    }

    .btn {
        grid-column: 1/-1;
        justify-self: start
    }

    .book {
        max-width: 260px
    }
}

.section1 {
    margin-top: 100px;
}

.video {
    aspect-ratio: 9 / 16;
    max-width: 300px;
}

.stack-img {
    max-height: 420px;
    object-fit: contain;
}

.download-section {
    background: #000;
}

.book-side-img {
    width: 100%;
    max-height: 560px;
}

.form-wrapper {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.hero__form {
    background: none;
    color: #fff;
    padding: 0;
}

.hero__form label span {
    color: #fff !important;
}

.hero__form-title {
    font-size: 28px;
}

@media screen and (max-width: 600px) {
    .grid-2 {
display: flex;
flex-direction: column;
    }

    .reverse-grid {
        flex-direction: column-reverse;
    }

    .contacts-title {
        font-size: 25px;
        margin-bottom: 12px;
    }

    .video {
        max-width: 100%;
    }

    .stack-img {
        max-height: 300px;
    }

    .hero__form-title {
        font-size: 20px;
    }

    .form-wrapper {
        flex-direction: column-reverse;
    }

    .book-side-img {
        max-height: 160px;
    }

    .section {
        padding: 26px 0;
    }
}