*,
*::before,
*::after {
    box-sizing: border-box;
}

:root {
    --bg-mts-spot-tl: #ffffff;
    --bg-mts-spot-br: #ffffff;
    --bg-mts-grad-a: #ffffff;
    --bg-mts-grad-b: #ffffff;
    --bg-mts-grad-c: #ffffff;
    --bg-mts-html: #ffffff;
    --bg-mts-crest-rgb: 245, 179, 255;
    --bg-mts-shadow-rgb: 0, 0, 255;
    --bg-mts-crest-a: 0.57;
    --bg-mts-crest-a-mid: 0.23;
    --bg-mts-shadow-a: 0.26;
    --bg-mts-shadow-a-fade: 0.08;
    --bg-mts-waves-opacity: 0.74;
}

html,
body {
    margin: 0;
    min-height: 100%;
    min-height: 100svh;
}

body.bg-mts-page {
    display: flex;
    flex-direction: column;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    color: #fff;
    background: #000;
    overflow: hidden;
    --bg-mts-waves-opacity: 0.9;
}

.bg-mts-top,
.bg-mts-bottom {
    flex: 0 0 auto;
    background: #000;
    z-index: 2;
}

.bg-mts-top {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 48px;
    padding: 0 1rem;
}

.bg-mts-top__title {
    font-size: 1.05rem;
    font-weight: 600;
    letter-spacing: 0.01em;
}

.bg-mts-bottom {
    height: 72px;
}

.bg-mts-stage {
    position: relative;
    flex: 1 1 auto;
    min-height: 0;
    overflow: hidden;
    isolation: isolate;
    background:
        radial-gradient(ellipse 90% 70% at 8% 0%, var(--bg-mts-spot-tl) 0%, transparent 52%),
        radial-gradient(ellipse 70% 55% at 70% 85%, var(--bg-mts-spot-br) 0%, transparent 55%),
        linear-gradient(155deg, var(--bg-mts-grad-a) 0%, var(--bg-mts-grad-b) 42%, var(--bg-mts-grad-c) 100%);
}

.bg-mts-canvas {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    display: none;
    pointer-events: none;
}

/* Site-wide fixed backdrop */
.site-bg-mts {
    display: block;
    position: fixed;
    inset: 0;
    width: 100%;
    height: 100%;
    height: 100svh;
    z-index: 0;
    pointer-events: none;
    overflow: hidden;
    isolation: isolate;
    background:
        radial-gradient(ellipse 90% 70% at 8% 0%, var(--bg-mts-spot-tl) 0%, transparent 52%),
        radial-gradient(ellipse 70% 55% at 70% 85%, var(--bg-mts-spot-br) 0%, transparent 55%),
        linear-gradient(155deg, var(--bg-mts-grad-a) 0%, var(--bg-mts-grad-b) 42%, var(--bg-mts-grad-c) 100%);
}

.site-bg-mts .bg-mts-waves {
    z-index: 0;
}

.site-bg-mts .bg-mts-canvas--site {
    position: absolute;
    inset: 0;
}

html.bg-mts-webgl .bg-mts-canvas {
    display: block;
}

html.bg-mts-webgl .bg-mts-waves {
    display: none;
}

.bg-mts-waves {
    position: absolute;
    inset: 0;
    pointer-events: none;
    overflow: hidden;
    opacity: var(--bg-mts-waves-opacity);
}

.bg-mts-wave {
    position: absolute;
    left: 0;
    top: 0;
    width: 220vmax;
    height: 220vmax;
    border-radius: 50%;
    transform-origin: center center;
    will-change: transform, opacity;
    background: radial-gradient(
        circle at center,
        transparent 0%,
        transparent 55%,
        rgba(var(--bg-mts-crest-rgb), var(--bg-mts-crest-a)) 58.5%,
        rgba(var(--bg-mts-crest-rgb), var(--bg-mts-crest-a-mid)) 60.5%,
        rgba(var(--bg-mts-shadow-rgb), var(--bg-mts-shadow-a)) 63%,
        rgba(var(--bg-mts-shadow-rgb), var(--bg-mts-shadow-a-fade)) 65.5%,
        transparent 69%
    );
    filter: none;
    opacity: 0;
    animation-duration: 50s;
    animation-timing-function: linear;
    animation-iteration-count: infinite;
}

/* s1: 2 ряби · верх-лево */
.bg-mts-wave--s1r1 { animation-name: bg-mts-s1-r1; }
.bg-mts-wave--s1r2 { animation-name: bg-mts-s1-r2; }

/* s2: 4 ряби · верх-право */
.bg-mts-wave--s2r1 { animation-name: bg-mts-s2-r1; }
.bg-mts-wave--s2r2 { animation-name: bg-mts-s2-r2; }
.bg-mts-wave--s2r3 { animation-name: bg-mts-s2-r3; }
.bg-mts-wave--s2r4 { animation-name: bg-mts-s2-r4; }

/* s3: 3 ряби · низ-лево */
.bg-mts-wave--s3r1 { animation-name: bg-mts-s3-r1; }
.bg-mts-wave--s3r2 { animation-name: bg-mts-s3-r2; }
.bg-mts-wave--s3r3 { animation-name: bg-mts-s3-r3; }

/* s4: 2 ряби · верх-центр */
.bg-mts-wave--s4r1 { animation-name: bg-mts-s4-r1; }
.bg-mts-wave--s4r2 { animation-name: bg-mts-s4-r2; }

/*
  Цикл 50 с. Источники: 0 → ~11 → ~22 → ~34 с.
  Пачки: 2 / 4 / 3 / 2. Рябь живёт ~15 с.
*/

/* s1 · 2 · -62%, -68% · старт 0 с */
@keyframes bg-mts-s1-r1 {
    0% { transform: translate(-62%, -68%) scale(0.18); opacity: 0.82; }
    20% { opacity: 0.28; }
    30% { transform: translate(-62%, -68%) scale(1.12); opacity: 0; }
    30.01%, 100% { transform: translate(-62%, -68%) scale(1.12); opacity: 0; }
}
@keyframes bg-mts-s1-r2 {
    0%, 2.4% { transform: translate(-62%, -68%) scale(0.18); opacity: 0; }
    2.5% { transform: translate(-62%, -68%) scale(0.18); opacity: 0.82; }
    22.5% { opacity: 0.28; }
    32.5% { transform: translate(-62%, -68%) scale(1.12); opacity: 0; }
    32.51%, 100% { transform: translate(-62%, -68%) scale(1.12); opacity: 0; }
}

/* s2 · 4 · -28%, -70% · старт 18 с = 22.5% */
@keyframes bg-mts-s2-r1 {
    0%, 22.4% { transform: translate(-28%, -70%) scale(0.18); opacity: 0; }
    22.5% { transform: translate(-28%, -70%) scale(0.18); opacity: 0.82; }
    42.5% { opacity: 0.28; }
    52.5% { transform: translate(-28%, -70%) scale(1.12); opacity: 0; }
    52.51%, 100% { transform: translate(-28%, -70%) scale(1.12); opacity: 0; }
}
@keyframes bg-mts-s2-r2 {
    0%, 24.9% { transform: translate(-28%, -70%) scale(0.18); opacity: 0; }
    25% { transform: translate(-28%, -70%) scale(0.18); opacity: 0.82; }
    45% { opacity: 0.28; }
    55% { transform: translate(-28%, -70%) scale(1.12); opacity: 0; }
    55.01%, 100% { transform: translate(-28%, -70%) scale(1.12); opacity: 0; }
}
@keyframes bg-mts-s2-r3 {
    0%, 27.4% { transform: translate(-28%, -70%) scale(0.18); opacity: 0; }
    27.5% { transform: translate(-28%, -70%) scale(0.18); opacity: 0.82; }
    47.5% { opacity: 0.28; }
    57.5% { transform: translate(-28%, -70%) scale(1.12); opacity: 0; }
    57.51%, 100% { transform: translate(-28%, -70%) scale(1.12); opacity: 0; }
}
@keyframes bg-mts-s2-r4 {
    0%, 29.9% { transform: translate(-28%, -70%) scale(0.18); opacity: 0; }
    30% { transform: translate(-28%, -70%) scale(0.18); opacity: 0.82; }
    50% { opacity: 0.28; }
    60% { transform: translate(-28%, -70%) scale(1.12); opacity: 0; }
    60.01%, 100% { transform: translate(-28%, -70%) scale(1.12); opacity: 0; }
}

/* s3 · 3 · -65%, -32% · старт 36 с = 45% */
@keyframes bg-mts-s3-r1 {
    0%, 44.9% { transform: translate(-65%, -32%) scale(0.18); opacity: 0; }
    45% { transform: translate(-65%, -32%) scale(0.18); opacity: 0.82; }
    65% { opacity: 0.28; }
    75% { transform: translate(-65%, -32%) scale(1.12); opacity: 0; }
    75.01%, 100% { transform: translate(-65%, -32%) scale(1.12); opacity: 0; }
}
@keyframes bg-mts-s3-r2 {
    0%, 47.4% { transform: translate(-65%, -32%) scale(0.18); opacity: 0; }
    47.5% { transform: translate(-65%, -32%) scale(0.18); opacity: 0.82; }
    67.5% { opacity: 0.28; }
    77.5% { transform: translate(-65%, -32%) scale(1.12); opacity: 0; }
    77.51%, 100% { transform: translate(-65%, -32%) scale(1.12); opacity: 0; }
}
@keyframes bg-mts-s3-r3 {
    0%, 49.9% { transform: translate(-65%, -32%) scale(0.18); opacity: 0; }
    50% { transform: translate(-65%, -32%) scale(0.18); opacity: 0.82; }
    70% { opacity: 0.28; }
    80% { transform: translate(-65%, -32%) scale(1.12); opacity: 0; }
    80.01%, 100% { transform: translate(-65%, -32%) scale(1.12); opacity: 0; }
}

/* s4 · 2 · -42%, -72% · старт 54 с = 67.5% */
@keyframes bg-mts-s4-r1 {
    0%, 67.4% { transform: translate(-42%, -72%) scale(0.18); opacity: 0; }
    67.5% { transform: translate(-42%, -72%) scale(0.18); opacity: 0.82; }
    87.5% { opacity: 0.28; }
    97.5% { transform: translate(-42%, -72%) scale(1.12); opacity: 0; }
    97.51%, 100% { transform: translate(-42%, -72%) scale(1.12); opacity: 0; }
}
@keyframes bg-mts-s4-r2 {
    0%, 69.9% { transform: translate(-42%, -72%) scale(0.18); opacity: 0; }
    70% { transform: translate(-42%, -72%) scale(0.18); opacity: 0.82; }
    90% { opacity: 0.28; }
    100% { transform: translate(-42%, -72%) scale(1.12); opacity: 0; }
}

html.bg-motion-off .bg-mts-wave {
    animation: none;
    opacity: 0;
    transform: none;
}

@media (prefers-reduced-motion: reduce) {
    .bg-mts-wave {
        animation: none;
        opacity: 0;
    }
}


.bg-mts-label {
    position: absolute;
    left: 50%;
    top: 54%;
    transform: translate(-50%, -50%);
    margin: 0;
    z-index: 1;
    display: inline-flex;
    align-items: center;
    gap: 0.55rem;
    font-size: clamp(1.6rem, 4.5vw, 2.35rem);
    font-weight: 700;
    letter-spacing: -0.02em;
    color: #4c3d6e;
    text-shadow: 0 1px 0 rgba(255, 255, 255, 0.55);
    pointer-events: none;
    user-select: none;
}

.bg-mts-label__icon {
    width: 0;
    height: 0;
    border-style: solid;
    border-width: 0.42em 0 0.42em 0.72em;
    border-color: transparent transparent transparent #4c3d6e;
    margin-top: 0.08em;
}

.bg-mts-motion-toggle {
    position: fixed;
    right: 14px;
    bottom: 88px;
    z-index: 5;
    width: 40px;
    height: 40px;
    border: 0;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.14);
    color: #fff;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
}

.bg-mts-motion-toggle:hover {
    background: rgba(255, 255, 255, 0.22);
}

.bg-mts-motion-toggle .icon-play {
    display: none;
}

html.bg-motion-off .bg-mts-motion-toggle .icon-pause {
    display: none;
}

html.bg-motion-off .bg-mts-motion-toggle .icon-play {
    display: block;
}

@media (max-width: 640px) {
    .bg-mts-top {
        height: 44px;
    }

    .bg-mts-bottom {
        height: 64px;
    }

    .bg-mts-motion-toggle {
        bottom: 78px;
        right: 12px;
    }
}