/* ==========================================================
   Динамический фон сайта
   Файл: assets/css/background.css
   ========================================================== */

/*
|--------------------------------------------------------------------------
| Обычный фон сайта, когда динамический фон выключен
|--------------------------------------------------------------------------
*/

html,
body {
    min-height: 100%;
}

body {
    position: relative;

    isolation: isolate;
}

:root[data-theme="dark"] body {
    background-color: #0b1220;
}

:root[data-theme="light"] body {
    background-color: #eef3f9;
}

/*
|--------------------------------------------------------------------------
| Контейнер динамического фона
|--------------------------------------------------------------------------
*/

.site-background-manager {
    position: fixed;
    z-index: 0;
    inset: 0;

    width: 100%;
    height: 100%;

    overflow: hidden;

    pointer-events: none;

    background: #07101d;

    opacity: 1;
    visibility: visible;

    transition:
        opacity 0.45s ease,
        visibility 0.45s ease;
}

/*
|--------------------------------------------------------------------------
| Фон выключен пользователем
|--------------------------------------------------------------------------
|
| display: none важен:
| контейнер вместе с чёрным background полностью исчезает.
|
*/

.site-background-manager.is-disabled {
    display: none;

    opacity: 0;
    visibility: hidden;
}

/*
|--------------------------------------------------------------------------
| Слои изображений
|--------------------------------------------------------------------------
*/

.site-background-layer {
    position: absolute;
    z-index: 1;
    inset: -4%;

    width: 108%;
    height: 108%;

    opacity: 0;

    background-repeat: no-repeat;
    background-position: center center;
    background-size: cover;

    filter:
        saturate(1.14)
        contrast(1.08)
        brightness(0.82);

    transform: scale(1.05);

    transition:
        opacity 4.5s ease-in-out,
        transform 22s ease-out,
        filter 4.5s ease-in-out;

    will-change:
        opacity,
        transform;
}

.site-background-layer.is-visible {
    opacity: 1;

    filter:
        saturate(1.20)
        contrast(1.12)
        brightness(0.88);

    transform: scale(1.14);
}

/*
|--------------------------------------------------------------------------
| Затемняющий / осветляющий слой
|--------------------------------------------------------------------------
*/

.site-background-overlay {
    position: absolute;
    z-index: 2;
    inset: 0;

    pointer-events: none;
}

/*
|--------------------------------------------------------------------------
| Тёмная тема
|--------------------------------------------------------------------------
*/

:root[data-theme="dark"] .site-background-manager {
    background: #07101d;
}

:root[data-theme="dark"] .site-background-overlay {
    background:
        radial-gradient(
            ellipse at 50% 0%,
            rgba(41, 87, 155, 0.19) 0%,
            transparent 52%
        ),
        radial-gradient(
            ellipse at 85% 82%,
            rgba(127, 28, 155, 0.10) 0%,
            transparent 50%
        ),
        linear-gradient(
            180deg,
            rgba(3, 8, 18, 0.73) 0%,
            rgba(5, 11, 22, 0.60) 48%,
            rgba(3, 8, 18, 0.86) 100%
        );
}

/*
|--------------------------------------------------------------------------
| Светлая тема
|--------------------------------------------------------------------------
*/

:root[data-theme="light"] .site-background-manager {
    background: #eef3f9;
}

:root[data-theme="light"] .site-background-overlay {
    background:
        radial-gradient(
            ellipse at 50% 0%,
            rgba(101, 154, 228, 0.18) 0%,
            transparent 52%
        ),
        linear-gradient(
            180deg,
            rgba(244, 248, 255, 0.78) 0%,
            rgba(244, 248, 255, 0.66) 48%,
            rgba(244, 248, 255, 0.85) 100%
        );
}

/*
|--------------------------------------------------------------------------
| CRT-линии старого монитора
|--------------------------------------------------------------------------
*/

.site-background-manager::before {
    position: absolute;
    z-index: 3;
    inset: 0;

    content: "";

    pointer-events: none;

    opacity: 0.24;

    background:
        repeating-linear-gradient(
            0deg,
            rgba(0, 0, 0, 0.22) 0,
            rgba(0, 0, 0, 0.22) 1px,
            transparent 1px,
            transparent 4px
        );

    mix-blend-mode: overlay;
}

/*
|--------------------------------------------------------------------------
| Движущиеся цифровые / аналоговые помехи
|--------------------------------------------------------------------------
*/

.site-background-manager::after {
    position: absolute;
    z-index: 4;
    inset: -50%;

    width: 200%;
    height: 200%;

    content: "";

    pointer-events: none;

    opacity: 0.10;

    background:
        repeating-radial-gradient(
            circle at 17% 28%,
            rgba(255, 255, 255, 0.55) 0,
            rgba(255, 255, 255, 0.55) 1px,
            transparent 1px,
            transparent 4px
        ),
        repeating-radial-gradient(
            circle at 77% 63%,
            rgba(65, 155, 255, 0.35) 0,
            rgba(65, 155, 255, 0.35) 1px,
            transparent 1px,
            transparent 5px
        );

    mix-blend-mode: screen;

    animation:
        site-background-noise 0.18s steps(2) infinite,
        site-background-flicker 4.5s ease-in-out infinite;
}

@keyframes site-background-noise {
    0% {
        transform: translate(0, 0);
    }

    20% {
        transform: translate(-3%, 2%);
    }

    40% {
        transform: translate(3%, -1%);
    }

    60% {
        transform: translate(-1%, 4%);
    }

    80% {
        transform: translate(4%, -3%);
    }

    100% {
        transform: translate(0, 0);
    }
}

@keyframes site-background-flicker {
    0%,
    100% {
        opacity: 0.07;
    }

    48% {
        opacity: 0.11;
    }

    50% {
        opacity: 0.17;
    }

    52% {
        opacity: 0.09;
    }

    78% {
        opacity: 0.13;
    }
}

/*
|--------------------------------------------------------------------------
| Содержимое сайта поверх фона
|--------------------------------------------------------------------------
*/

.site-header,
main,
.site-main,
.page-content,
.site-content,
.site-footer {
    position: relative;
    z-index: 1;
}

/*
|--------------------------------------------------------------------------
| Кнопка включения / выключения фона
|--------------------------------------------------------------------------
*/

.background-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;

    width: 38px;
    height: 38px;
    padding: 0;

    cursor: pointer;

    color: var(--header-text, #edf4ff);
    background: rgba(127, 127, 127, 0.08);
    border: 1px solid var(
        --header-border,
        rgba(148, 163, 184, 0.18)
    );
    border-radius: 10px;

    font-size: 18px;
    line-height: 1;

    transition:
        color 0.2s ease,
        background 0.2s ease,
        opacity 0.2s ease,
        transform 0.2s ease;
}

.background-toggle:hover {
    background: rgba(96, 165, 250, 0.18);
    transform: translateY(-1px);
}

.background-toggle:focus-visible {
    outline: 2px solid #60a5fa;
    outline-offset: 2px;
}

.background-toggle.is-disabled {
    opacity: 0.45;
}

.background-toggle.is-disabled .background-toggle-icon {
    text-decoration: line-through;
}

/*
|--------------------------------------------------------------------------
| Планшеты и телефоны
|--------------------------------------------------------------------------
*/

@media (max-width: 700px) {
    .site-background-layer {
        inset: -3%;

        width: 106%;
        height: 106%;

        background-position: center top;
    }

    .site-background-manager::before {
        opacity: 0.16;
    }

    .site-background-manager::after {
        opacity: 0.06;
    }

    .background-toggle {
        width: 36px;
        height: 36px;
        border-radius: 9px;
    }
}

/*
|--------------------------------------------------------------------------
| Уменьшение анимации для пользователей с соответствующей
| системной настройкой
|--------------------------------------------------------------------------
*/

@media (prefers-reduced-motion: reduce) {
    .site-background-layer {
        transition: opacity 0.3s ease;
        transform: none;
    }

    .site-background-layer.is-visible {
        transform: none;
    }

    .site-background-manager::after {
        animation: none;
    }
}