:root {
    --triangle-color: #2196F3;
    --toggle-bar-color: #2196F3;
    --toggle-ball-color: #fff;
    --range-bar-color: #2196F3;
    --range-thumb-color: #fff;
    --range-thumb-shadow: 0 2px 8px rgba(0,0,0,0.15);
}

body.dark-mode {
    --toggle-bar-color: #fff;
    --toggle-ball-color: var(--triangle-color);
    --range-bar-color: var(--triangle-color);
    --range-thumb-color: var(--triangle-color);
    --range-thumb-shadow: 0 2px 8px rgba(255,255,255,0.15);
}

body {
    font-family: 'Segoe UI', Arial, sans-serif;
    text-align: center;
    background: #f9f9f9;
    color: #222;
    transition: background 0.3s, color 0.3s;
    font-size: 15px;
    letter-spacing: 0.015em;
}

body.dark-mode {
    background: #212121;
    color: #f9f9f9;
}

h1 {
    font-size: 2em;
    font-weight: bold;
    letter-spacing: 0.04em;
    margin-top: 40px;
}

.controls {
    margin-bottom: 20px;
    font-size: 1em;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

label, input, span {
    font-size: 1em;
}

canvas {
    background: inherit;
    transition: box-shadow 0.6s cubic-bezier(.68,-0.55,.27,1.55), background 0.3s;
    margin-top: 20px;
    border-radius: 16px;
    border: none;
    box-shadow: 0 2px 14px 0 rgba(0,0,0,0.12);
}

body.dark-mode canvas {
    background: inherit;
    box-shadow: 0 4px 28px 0 rgba(0,0,0,0.32), 0 1.5px 2px rgba(255,255,255,0.12) inset;
}

.mode-toggle {
    position: absolute;
    top: 20px;
    right: 40px;
    display: flex;
    align-items: center;
    z-index: 100;
}

.switch {
    position: relative;
    display: inline-block;
    width: 50px;
    height: 26px;
    margin-right: 8px;
}

.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0; left: 0; right: 0; bottom: 0;
    background-color: var(--toggle-bar-color);
    transition: .4s;
    border-radius: 26px;
}

.slider:before {
    position: absolute;
    content: "";
    height: 20px; width: 20px;
    left: 3px; bottom: 3px;
    background-color: var(--toggle-ball-color);
    transition: .4s;
    border-radius: 50%;
    box-shadow: 0 2px 4px rgba(0,0,0,0.12);
}

input:checked + .slider {
    background-color: var(--toggle-bar-color);
}
input:checked + .slider:before {
    background-color: var(--toggle-ball-color);
    transform: translateX(24px);
}

/* Custom Modern Range Slider */
input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    width: 180px;
    height: 8px;
    background: transparent;
    margin: 0 10px;
}

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

input[type="range"]::-webkit-slider-runnable-track {
    height: 8px;
    background: var(--range-bar-color);
    border-radius: 4px;
    box-shadow: 0 1px 4px rgba(0,0,0,0.12);
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--range-thumb-color);
    box-shadow: var(--range-thumb-shadow);
    border: 2px solid var(--range-bar-color);
    margin-top: -6px;
    transition: background .3s, border-color .3s;
}

input[type="range"]:focus::-webkit-slider-thumb {
    outline: 2px solid #666;
}

input[type="range"]::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--range-thumb-color);
    box-shadow: var(--range-thumb-shadow);
    border: 2px solid var(--range-bar-color);
    transition: background .3s, border-color .3s;
}

input[type="range"]::-moz-range-track {
    height: 8px;
    background: var(--range-bar-color);
    border-radius: 4px;
    box-shadow: 0 1px 4px rgba(0,0,0,0.12);
}

input[type="range"]::-ms-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--range-thumb-color);
    box-shadow: var(--range-thumb-shadow);
    border: 2px solid var(--range-bar-color);
    transition: background .3s, border-color .3s;
}

input[type="range"]::-ms-fill-lower,
input[type="range"]::-ms-fill-upper {
    background: var(--range-bar-color);
    border-radius: 4px;
    box-shadow: 0 1px 4px rgba(0,0,0,0.12);
}

input[type="range"] {
    accent-color: var(--range-bar-color);
}