:root {
    --bg-start: #091221;
    --bg-mid: #0f2a4a;
    --bg-end: #164070;
    --surface: rgba(20, 35, 70, 0.25);
    --surface-strong: rgba(25, 50, 100, 0.2);
    --surface-stronger: rgba(25, 50, 100, 0.35);
    --text-main: #ffffff;
    --text-soft: rgba(255, 255, 255, 0.65);
    --border-soft: rgba(255, 255, 255, 0.12);
    --shadow: rgba(0, 0, 0, 0.3);
    --accent: #5865f2;
}

* {
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: linear-gradient(135deg, var(--bg-start), var(--bg-mid), var(--bg-end));
    color: var(--text-main);
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    overflow-x: hidden;
    perspective: 1000px;
    position: relative;
    padding: 30px 0 36px;
    scrollbar-gutter: stable both-edges;
}

/* Header */
.top-header {
    position: static;
    display: flex;
    align-items: center;
    gap: 10px;
    z-index: 20;
    text-decoration: none;
    color: rgba(255, 255, 255, 0.85);
    background: var(--surface-strong);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.08);
    padding: 6px 14px;
    border-radius: 20px;
    box-shadow: 0 4px 15px var(--shadow);
    transition: all 0.3s ease;
}

.top-header:hover {
    color: var(--text-main);
    background: var(--surface-stronger);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.4);
}

.top-header i {
    font-size: 1.1rem;
    color: var(--accent);
}

.top-header span {
    font-size: 0.9rem;
    letter-spacing: 0.05em;
    font-weight: 500;
}

/* Tabs */
.nav-tabs {
    position: static;
    display: flex;
    justify-content: center;
    gap: 10px;
    z-index: 20;
    margin-top: 10px;
}

.tab-btn {
    background: var(--surface-strong);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.08);
    color: var(--text-soft);
    padding: 5px 16px;
    border-radius: 12px;
    cursor: pointer;
    font-size: 0.82rem;
    letter-spacing: 0.05em;
    font-weight: 500;
    transition: all 0.3s ease;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.25);
}

.tab-btn:hover {
    color: var(--text-main);
    background: rgba(25, 50, 100, 0.4);
}

.tab-btn.active {
    color: var(--text-main);
    background: rgba(45, 80, 150, 0.5);
    border-color: rgba(255, 255, 255, 0.2);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.4);
    animation: active-tab-pulse 1.9s ease-in-out infinite;
    -webkit-animation: active-tab-pulse 1.9s ease-in-out infinite;
}

@-webkit-keyframes active-tab-pulse {
    0%,
    100% {
        box-shadow: 0 4px 15px rgba(0, 0, 0, 0.4), 0 0 0 rgba(117, 176, 255, 0);
        border-color: rgba(255, 255, 255, 0.2);
        transform: scale(1);
    }
    50% {
        box-shadow: 0 6px 20px rgba(0, 0, 0, 0.45), 0 0 16px rgba(117, 176, 255, 0.5);
        border-color: rgba(175, 221, 255, 0.95);
        transform: scale(1.03);
    }
}

@keyframes active-tab-pulse {
    0%,
    100% {
        box-shadow: 0 4px 15px rgba(0, 0, 0, 0.4), 0 0 0 rgba(117, 176, 255, 0);
        border-color: rgba(255, 255, 255, 0.2);
        transform: scale(1);
    }
    50% {
        box-shadow: 0 6px 20px rgba(0, 0, 0, 0.45), 0 0 16px rgba(117, 176, 255, 0.5);
        border-color: rgba(175, 221, 255, 0.95);
        transform: scale(1.03);
    }
}

/* Main layout */
.page-center-wrapper {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
    z-index: 10;
    margin-top: 12px;
}

.card-container {
    width: 550px;
    max-width: 90vw;
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin: 0 auto;
    position: relative;
}

.card {
    background: var(--surface);
    backdrop-filter: blur(25px);
    -webkit-backdrop-filter: blur(25px);
    border: 1px solid var(--border-soft);
    box-shadow: 0 20px 45px rgba(0, 0, 0, 0.6), inset 0 0 15px rgba(255, 255, 255, 0.05);
    padding: 20px;
    border-radius: 24px;
    width: 100%;
    box-sizing: border-box;
    user-select: none;
    display: flex;
    flex-direction: column;
    gap: 12px;
    transition: transform 0.1s ease-out, box-shadow 0.3s ease;
    transform-style: preserve-3d;
}

.card:hover {
    box-shadow: 0 25px 50px rgba(0, 0, 0, 0.7), 0 0 20px rgba(100, 180, 255, 0.15), inset 0 0 20px rgba(255, 255, 255, 0.08);
}

.tab-content {
    display: none;
    width: 100%;
}

.tab-content.active-card {
    display: block;
}

.media-wrapper {
    pointer-events: none;
    overflow: hidden;
    border-radius: 12px;
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.4);
    background: rgba(0, 0, 0, 0.25);
    width: 100%;
    border: 1px solid rgba(255, 255, 255, 0.06);
}

.heatmap-img {
    width: 100%;
    display: block;
    -webkit-user-drag: none;
    border-radius: 10px;
    margin-top: 0;
    margin-bottom: 0;
    opacity: 0.95;
    filter: brightness(1.15) contrast(1.05);
}

.rok-video {
    width: 100%;
    height: 240px;
    object-fit: contain;
    display: block;
    border-radius: 10px;
    background: #000;
    pointer-events: auto;
}

.audio-container {
    width: 100%;
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    background: rgba(15, 30, 60, 0.4);
    border: 1px solid rgba(255, 255, 255, 0.08);
    padding: 12px 16px;
    border-radius: 16px;
}

#lyrics-display {
    font-size: 0.9rem;
    letter-spacing: 0.05em;
    color: rgba(255, 255, 255, 0.95);
    height: 20px;
    text-align: center;
    transition: opacity 0.4s ease-in-out, transform 0.4s ease-in-out;
    opacity: 0;
    transform: translateY(5px);
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.8);
}

#play-btn {
    background: rgba(255, 255, 255, 0.15);
    border: 1px solid rgba(255, 255, 255, 0.25);
    color: white;
    padding: 5px 20px;
    border-radius: 10px;
    cursor: pointer;
    font-size: 0.82rem;
    letter-spacing: 0.05em;
    transition: all 0.3s ease;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
    text-align: center;
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 0 auto;
}

#play-btn:hover {
    background: rgba(255, 255, 255, 0.25);
    transform: scale(1.05);
    box-shadow: 0 4px 15px rgba(255, 255, 255, 0.2);
}

.card-external-footer {
    width: 100%;
    text-align: center;
    font-size: 0.74rem;
    color: rgba(255, 255, 255, 0.6);
    letter-spacing: 0.04em;
    text-shadow: 0 1px 3px rgba(0, 0, 0, 0.8);
    box-sizing: border-box;
    line-height: 1.4;
}

.card-external-footer div {
    display: block;
}

/* Side menu */
.rok-side-menu {
    position: relative;
    left: auto;
    top: auto;
    display: none;
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: center;
    gap: 8px;
    width: 100%;
    margin-top: 2px;
    z-index: 25;
}

.rok-side-menu.show {
    display: flex;
}

.rok-sub-btn-wrapper {
    position: relative;
    display: inline-block;
}

.rok-menu-hint {
    width: 100%;
    text-align: center;
    font-size: 0.74rem;
    letter-spacing: 0.04em;
    color: rgba(255, 255, 255, 0.78);
    margin-bottom: 2px;
    text-shadow: 0 1px 4px rgba(0, 0, 0, 0.55);
}

.rok-sub-btn {
    background: rgba(25, 50, 100, 0.3);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.12);
    color: rgba(255, 255, 255, 0.85);
    padding: 10px 16px;
    border-radius: 14px;
    cursor: pointer;
    font-size: 0.85rem;
    letter-spacing: 0.02em;
    font-weight: 500;
    line-height: 1.4;
    min-height: 40px;
    font-family: "Segoe UI", "Yu Gothic UI", "Meiryo", Arial, sans-serif;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
    transition: all 0.3s ease;
    text-align: center;
    display: flex;
    justify-content: center;
    align-items: center;
    width: fit-content;
    min-width: 118px;
    white-space: nowrap !important;
    word-break: keep-all;
    overflow-wrap: normal;
    flex-shrink: 0;
    overflow: visible;
}

@media (min-width: 951px) {
    .rok-sub-btn-wrapper {
        flex: 0 0 auto;
        min-width: max-content;
    }

    .rok-sub-btn {
        width: fit-content;
        min-width: 118px;
    }
}

.rok-sub-btn:hover {
    background: rgba(50, 90, 170, 0.5);
    color: #ffffff;
    transform: scale(1.05);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.4);
}

.rok-sub-btn.soga-btn {
    border-color: rgba(170, 225, 255, 0.75);
    background: linear-gradient(145deg, rgba(36, 72, 140, 0.58), rgba(24, 54, 108, 0.55));
    box-shadow: 0 0 0 0 rgba(120, 210, 255, 0.45), 0 6px 18px rgba(50, 140, 220, 0.32);
    animation: soga-pulse 2.2s ease-in-out infinite;
    position: relative;
    overflow: visible;
    will-change: box-shadow, transform;
}

.rok-sub-btn.soga-btn:hover {
    border-color: rgba(210, 242, 255, 0.95);
    background: linear-gradient(145deg, rgba(54, 104, 192, 0.66), rgba(35, 77, 152, 0.62));
}

.rok-sub-btn.soga-btn::after {
    content: "";
    position: absolute;
    inset: -4px;
    border-radius: 16px;
    border: 1px solid rgba(165, 225, 255, 0.8);
    pointer-events: none;
    animation: soga-ring-pulse 2.2s ease-out infinite;
}

@keyframes soga-pulse {
    0%,
    100% {
        box-shadow: 0 0 0 0 rgba(120, 210, 255, 0.45), 0 6px 18px rgba(50, 140, 220, 0.32);
        transform: translateZ(0) scale(1);
    }
    50% {
        box-shadow: 0 0 0 10px rgba(120, 210, 255, 0), 0 10px 24px rgba(90, 190, 255, 0.55);
        transform: translateZ(0) scale(1.02);
    }
}

@keyframes soga-ring-pulse {
    0% {
        opacity: 0.9;
        transform: scale(1);
    }
    70% {
        opacity: 0;
        transform: scale(1.18);
    }
    100% {
        opacity: 0;
        transform: scale(1.18);
    }
}

@media (hover: none) {
    .rok-sub-btn.soga-btn {
        animation-duration: 1.8s;
    }

    .rok-sub-btn.soga-btn::after {
        inset: -3px;
    }
}

.tooltip {
    position: absolute;
    left: calc(100% + 12px);
    top: 50%;
    transform: translateY(-50%) translateX(-8px);
    background: rgba(15, 30, 60, 0.9);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.12);
    color: #ffffff;
    padding: 6px 12px;
    border-radius: 8px;
    font-size: 0.75rem;
    letter-spacing: 0.05em;
    white-space: nowrap;
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity 0.3s ease, transform 0.3s ease, visibility 0.3s ease;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
    z-index: 30;
}

.rok-sub-btn-wrapper:hover .tooltip {
    opacity: 1;
    visibility: visible;
    transform: translateY(-50%) translateX(0);
}

.soga-popup-overlay {
    position: fixed;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(5, 12, 24, 0.5);
    backdrop-filter: blur(6px);
    -webkit-backdrop-filter: blur(6px);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity 0.25s ease, visibility 0.25s ease;
    z-index: 60;
}

.soga-popup-overlay.show {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
}

.soga-popup {
    width: min(92vw, 460px);
    background: rgba(18, 35, 68, 0.62);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 16px;
    box-shadow: 0 16px 40px rgba(0, 0, 0, 0.45);
    padding: 18px 18px 16px;
    position: relative;
}

.soga-popup-title {
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: 0.03em;
    margin-bottom: 8px;
}

.soga-popup-message {
    margin: 0;
    color: rgba(255, 255, 255, 0.92);
    line-height: 1.55;
    font-size: 0.9rem;
}

.soga-popup.centered .soga-popup-title,
.soga-popup.centered .soga-popup-message {
    text-align: center;
}

.soga-popup-close {
    position: absolute;
    top: 8px;
    right: 8px;
    width: 28px;
    height: 28px;
    border-radius: 999px;
    border: 1px solid rgba(255, 255, 255, 0.3);
    background: rgba(255, 255, 255, 0.08);
    color: #fff;
    font-size: 0.78rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.2s ease;
}

.soga-popup-close:hover {
    background: rgba(255, 255, 255, 0.2);
}

/* Snow canvases */
#falling-snow,
#accumulated-snow {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
}

#falling-snow {
    z-index: 1;
}

#accumulated-snow {
    z-index: 11;
}

@media (max-width: 950px) {
    body {
        justify-content: center;
        align-items: center;
        height: 100svh;
        min-height: 100svh;
        padding: 20px 14px 28px;
        gap: 10px;
        overflow-y: auto;
    }

    .top-header,
    .nav-tabs {
        position: static;
    }

    .top-header {
        width: fit-content;
        margin: 0 auto;
    }

    .nav-tabs {
        width: 100%;
        justify-content: center;
        flex-wrap: wrap;
        gap: 8px;
    }

    .tab-btn {
        min-width: 120px;
    }

    .page-center-wrapper {
        flex-direction: column;
        gap: 12px;
        margin-top: 0;
        width: 100%;
        align-items: center;
    }

    .card-container {
        width: min(100%, 550px);
        margin: 0 auto;
    }

    .card {
        padding: 16px;
    }

    .rok-side-menu {
        position: relative;
        left: auto;
        transform: none;
        flex-direction: row;
        flex-wrap: wrap;
        justify-content: center;
        gap: 6px;
        width: 100%;
        order: 0;
    }

    .card-external-footer {
        order: 1;
    }

    .rok-sub-btn-wrapper {
        flex: 1 1 90px;
        max-width: 140px;
    }

    .rok-side-menu.show {
        transform: none;
    }

    .rok-sub-btn {
        width: 100%;
        padding: 6px 4px;
        font-size: 0.72rem;
        border-radius: 10px;
    }

    .tooltip {
        left: 50%;
        top: calc(100% + 5px);
        transform: translateX(-50%) translateY(4px);
    }

    .rok-sub-btn-wrapper:hover .tooltip {
        transform: translateX(-50%) translateY(0);
    }

    .rok-video {
        height: 165px;
    }

    #play-btn {
        min-width: 120px;
    }
}

/* Keep labels unbroken when desktop users zoom in and hit mobile breakpoints. */
@media (max-width: 950px) and (hover: hover) {
    .rok-sub-btn-wrapper {
        flex: 0 0 auto;
        max-width: none;
        min-width: max-content;
    }

    .rok-sub-btn {
        width: fit-content;
        min-width: 118px;
        padding: 6px 10px;
        white-space: nowrap !important;
    }
}

@media (max-width: 560px) {
    body {
        padding: 14px 10px 24px;
    }

    .card-container {
        max-width: 100%;
    }

    .heatmap-img {
        margin-top: 0;
        margin-bottom: 0;
    }

    .tab-btn {
        min-width: 105px;
        padding: 6px 12px;
        font-size: 0.78rem;
    }

    .card {
        border-radius: 18px;
        padding: 14px;
        gap: 10px;
    }

    .audio-container {
        padding: 10px 10px;
    }

    #play-btn {
        width: 100%;
    }

    .rok-video {
        height: 150px;
    }
}