:root {
    --light-color: #b826ff;
    /* BTS purple default */
    --brightness: 0.8;
    --bg-color-base: #06050a;
    --font-main: 'Inter', sans-serif;
    --glow-spread: calc(100px * var(--brightness) + 10px);
    --bulb-opacity: calc(0.2 + (0.8 * var(--brightness)));
    --neon-shadow: 0 0 10px var(--light-color), 0 0 30px var(--light-color);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background-color: var(--bg-color-base);
    color: #ffffff;
    font-family: var(--font-main);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    overflow: hidden;
    position: relative;
    background-image: radial-gradient(circle at 15% 50%, rgba(255, 255, 255, 0.02) 0%, transparent 50%),
        radial-gradient(circle at 85% 30%, rgba(255, 255, 255, 0.02) 0%, transparent 50%);
}

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

/* Background Ambient Glow that dynamically reflects the army bomb color */
.ambient-light {
    position: absolute;
    top: 50%;
    left: 40%;
    width: 70vw;
    height: 70vw;
    background: radial-gradient(circle, var(--light-color) 0%, transparent 70%);
    opacity: calc(var(--brightness) * 0.18);
    transform: translate(-50%, -50%);
    z-index: 0;
    pointer-events: none;
    transition: background 0.4s ease, opacity 0.4s ease;
    mix-blend-mode: screen;
}

.app-container {
    display: flex;
    flex-direction: row;
    width: 100%;
    max-width: 1100px;
    height: 85vh;
    background: rgba(20, 20, 25, 0.4);
    backdrop-filter: blur(25px);
    -webkit-backdrop-filter: blur(25px);
    border-radius: 30px;
    border: 1px solid rgba(255, 255, 255, 0.08);
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.6), inset 0 0 20px rgba(255, 255, 255, 0.02);
    z-index: 10;
    overflow: hidden;
    position: relative;
}

/* Lightstick Area */
.lightstick-container {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    padding: 2rem;
}

.army-bomb {
    height: 100%;
    max-height: 70vh;
    -webkit-filter: drop-shadow(0 0 var(--glow-spread) var(--light-color));
    filter: drop-shadow(0 0 var(--glow-spread) var(--light-color));
    transition: filter 0.4s ease, -webkit-filter 0.4s ease;
    z-index: 2;
    animation: float 6s ease-in-out infinite;
    overflow: visible;
    pointer-events: none;
}

.bulb-color {
    transition: fill 0.4s ease, opacity 0.4s ease;
    opacity: var(--bulb-opacity);
}

.bts-shield {
    transition: opacity 0.4s ease;
    opacity: calc(var(--bulb-opacity) * 1.5);
    /* Shield stays slightly more visible */
}

@keyframes float {
    0% {
        transform: translateY(0px) rotate(0deg);
    }

    50% {
        transform: translateY(-15px) rotate(2deg);
    }

    100% {
        transform: translateY(0px) rotate(0deg);
    }
}

@keyframes flicker {

    0%,
    100% {
        opacity: var(--bulb-opacity);
    }

    10% {
        opacity: 0;
    }

    20% {
        opacity: var(--bulb-opacity);
    }

    25%,
    35% {
        opacity: 0;
    }

    40% {
        opacity: var(--bulb-opacity);
    }

    70% {
        opacity: calc(var(--bulb-opacity)/2);
    }

    75% {
        opacity: var(--bulb-opacity);
    }
}

.flicker-active .bulb-color,
.flicker-active .bts-shield {
    animation: flicker 0.6s infinite alternate;
}

/* Controls Area */
.controls-panel {
    width: 420px;
    background: rgba(10, 10, 15, 0.6);
    padding: 3rem 2.5rem;
    display: flex;
    flex-direction: column;
    border-left: 1px solid rgba(255, 255, 255, 0.08);
    z-index: 5;
    position: relative;
}

/* Side decorative line */
.controls-panel::before {
    content: '';
    position: absolute;
    left: 0;
    top: 10%;
    height: 80%;
    width: 2px;
    background: linear-gradient(to bottom, transparent, var(--light-color), transparent);
    opacity: calc(var(--brightness) * 0.5);
    transition: all 0.4s ease;
}

.controls-panel h2 {
    font-size: 2.2rem;
    font-weight: 800;
    letter-spacing: 2px;
    background: linear-gradient(90deg, #fff, #bbb);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.2rem;
}

.controls-panel p {
    color: #888;
    font-size: 0.7rem;
    margin-bottom: 3rem;
    text-transform: uppercase;
    letter-spacing: 2px;
    font-weight: 600;
}

.control-group {
    margin-bottom: 2rem;
}

.control-group label {
    display: block;
    font-size: 0.9rem;
    color: #ccc;
    margin-bottom: 1rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    font-weight: 600;
}

/* Color Options */
.color-options {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
}

.color-btn {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 2px solid rgba(255, 255, 255, 0.2);
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.5);
}

.color-btn:hover {
    transform: scale(1.15) translateY(-2px);
}

.color-btn.active {
    border-color: #fff;
    transform: scale(1.2);
    box-shadow: 0 0 20px currentColor;
}

.custom-color-wrapper {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    overflow: hidden;
    border: 2px solid rgba(255, 255, 255, 0.2);
    cursor: pointer;
    position: relative;
    background: conic-gradient(red, yellow, lime, aqua, blue, magenta, red);
    transition: all 0.3s ease;
}

.custom-color-wrapper:hover {
    transform: scale(1.15) translateY(-2px);
}

.custom-color-wrapper input[type="color"] {
    position: absolute;
    top: -10px;
    left: -10px;
    width: 60px;
    height: 60px;
    cursor: pointer;
    opacity: 0;
}

.custom-color-wrapper.active {
    border-color: #fff;
    transform: scale(1.2);
    box-shadow: 0 0 20px var(--light-color);
}

/* Slider */
.slider-wrapper {
    display: flex;
    align-items: center;
    gap: 15px;
}

.icon {
    font-size: 1.4rem;
    color: #666;
    transition: color 0.3s;
}

.slider-wrapper:hover .icon {
    color: #999;
}

input[type=range] {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    background: transparent;
}

input[type=range]::-webkit-slider-thumb {
    -webkit-appearance: none;
    height: 24px;
    width: 24px;
    border-radius: 50%;
    background: #fff;
    cursor: pointer;
    margin-top: -10px;
    box-shadow: 0 0 15px var(--light-color);
    transition: transform 0.2s, box-shadow 0.2s;
}

input[type=range]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
    box-shadow: 0 0 25px var(--light-color);
}

input[type=range]::-webkit-slider-runnable-track {
    width: 100%;
    height: 4px;
    cursor: pointer;
    background: rgba(255, 255, 255, 0.15);
    border-radius: 2px;
}

input[type=range]:focus {
    outline: none;
}

/* Power Button */
.power-toggle {
    width: 100%;
    padding: 1.2rem;
    background: rgba(255, 255, 255, 0.05);
    color: #fff;
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 800;
    cursor: pointer;
    transition: all 0.3s ease;
    letter-spacing: 2px;
    text-shadow: 0 0 10px rgba(255, 255, 255, 0.5);
    position: relative;
    overflow: hidden;
}

.power-toggle::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.1), transparent);
    transition: left 0.5s;
}

.power-toggle:hover::before {
    left: 100%;
}

.power-toggle:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.3);
}

.power-toggle.is-off {
    background: rgba(204, 0, 0, 0.1);
    color: #ff4444;
    border-color: rgba(255, 51, 51, 0.4);
    text-shadow: 0 0 10px rgba(204, 0, 0, 0.5);
}

.power-toggle.is-off:hover {
    background: rgba(204, 0, 0, 0.2);
}

/* Toggle Switch */
.toggle-switch {
    display: flex;
    align-items: center;
}

.toggle-switch input {
    display: none;
}

.switch-label {
    position: relative;
    display: inline-block;
    width: 56px;
    height: 30px;
    background-color: #333;
    border-radius: 34px;
    cursor: pointer;
    transition: background-color 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.switch-label::after {
    content: "";
    position: absolute;
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background-color: #fff;
    top: 3px;
    left: 4px;
    transition: transform 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.3);
}

input:checked+.switch-label {
    background-color: var(--light-color);
    box-shadow: 0 0 15px var(--light-color);
}

input:checked+.switch-label::after {
    transform: translateX(24px);
}

/* SVG ID hover */
#power-btn-area {
    cursor: pointer;
    transition: filter 0.2s;
    pointer-events: auto;
}

#power-btn-area:hover {
    filter: brightness(1.2);
}

/* Responsive */
@media (max-width: 900px) {
    body {
        padding: 0;
    }

    .app-container {
        flex-direction: column;
        height: 100vh;
        border-radius: 0;
        border: none;
        overflow-y: auto;
    }

    .lightstick-container {
        height: 65vh;
        flex: none;
        padding: 1rem;
        padding-top: 4.5rem;
    }

    .ambient-light {
        top: 30%;
        left: 50%;
    }

    .controls-panel {
        width: 100%;
        flex: 1;
        border-left: none;
        border-top: 1px solid rgba(255, 255, 255, 0.1);
        padding: 2.5rem 2rem;
        background: rgba(10, 10, 15, 0.85);
        /* Darker on mobile */
    }

    .controls-panel h2 {
        font-size: 1.8rem;
    }

    .controls-panel::before {
        top: 0;
        left: 10%;
        width: 80%;
        height: 2px;
        background: linear-gradient(to right, transparent, var(--light-color), transparent);
    }
}