.material-symbols-outlined {
    font-variation-settings: 'FILL' 0, 'wght' 400, 'GRAD' 0, 'opsz' 24;
}

/* ===== Coin Flip 3D Core ===== */
.coin-scene {
    perspective: 900px;
    width: 200px;
    height: 200px;
    position: relative;
}

.coin-inner {
    position: relative;
    width: 100%;
    height: 100%;
    transform-style: preserve-3d;
    will-change: transform;
}

/* ===== Coin Faces (Heads & Tails) ===== */
.coin-face {
    position: absolute;
    width: 200px;
    height: 200px;
    border-radius: 50%;
    backface-visibility: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    left: 0;
    top: 0;
}

/* Heads — Gold Coin */
.coin-heads {
    transform: translateZ(6px);
    background:
        radial-gradient(circle at 50% 50%, #fff8dc 0%, #ffe066 5%, transparent 12%),
        radial-gradient(circle at 38% 36%, rgba(255,255,255,0.55) 0%, transparent 28%),
        radial-gradient(circle at 60% 55%, rgba(0,0,0,0.1) 0%, transparent 35%),
        conic-gradient(from 0deg,
            #b8860b 0deg, #ffd700 5deg, #daa520 10deg, #ffd700 15deg,
            #b8860b 20deg, #ffd700 25deg, #daa520 30deg, #ffd700 35deg,
            #b8860b 40deg, #ffd700 45deg, #daa520 50deg, #ffd700 55deg,
            #b8860b 60deg, #ffd700 65deg, #daa520 70deg, #ffd700 75deg,
            #b8860b 80deg, #ffd700 85deg, #daa520 90deg, #ffd700 95deg,
            #b8860b 100deg, #ffd700 105deg, #daa520 110deg, #ffd700 115deg,
            #b8860b 120deg, #ffd700 125deg, #daa520 130deg, #ffd700 135deg,
            #b8860b 140deg, #ffd700 145deg, #daa520 150deg, #ffd700 155deg,
            #b8860b 160deg, #ffd700 165deg, #daa520 170deg, #ffd700 175deg,
            #b8860b 180deg, #ffd700 185deg, #daa520 190deg, #ffd700 195deg,
            #b8860b 200deg, #ffd700 205deg, #daa520 210deg, #ffd700 215deg,
            #b8860b 220deg, #ffd700 225deg, #daa520 230deg, #ffd700 235deg,
            #b8860b 240deg, #ffd700 245deg, #daa520 250deg, #ffd700 255deg,
            #b8860b 260deg, #ffd700 265deg, #daa520 270deg, #ffd700 275deg,
            #b8860b 280deg, #ffd700 285deg, #daa520 290deg, #ffd700 295deg,
            #b8860b 300deg, #ffd700 305deg, #daa520 310deg, #ffd700 315deg,
            #b8860b 320deg, #ffd700 325deg, #daa520 330deg, #ffd700 335deg,
            #b8860b 340deg, #ffd700 345deg, #daa520 350deg, #ffd700 355deg,
            #b8860b 360deg
        );
    border: 3px solid #8b6914;
    box-shadow:
        inset 0 0 12px rgba(0,0,0,0.3),
        inset 0 0 40px rgba(0,0,0,0.1),
        0 0 0 1px rgba(139,105,20,0.6),
        0 0 0 4px rgba(184,134,11,0.35),
        0 0 0 7px rgba(139,105,20,0.2);
}

/* Tails — Silver Coin */
.coin-tails {
    transform: rotateX(180deg) translateZ(6px);
    background:
        radial-gradient(circle at 50% 50%, #f5f5f5 0%, #dcdcdc 5%, transparent 12%),
        radial-gradient(circle at 38% 36%, rgba(255,255,255,0.55) 0%, transparent 28%),
        radial-gradient(circle at 60% 55%, rgba(0,0,0,0.08) 0%, transparent 35%),
        conic-gradient(from 0deg,
            #808080 0deg, #c0c0c0 5deg, #a0a0a0 10deg, #c0c0c0 15deg,
            #808080 20deg, #c0c0c0 25deg, #a0a0a0 30deg, #c0c0c0 35deg,
            #808080 40deg, #c0c0c0 45deg, #a0a0a0 50deg, #c0c0c0 55deg,
            #808080 60deg, #c0c0c0 65deg, #a0a0a0 70deg, #c0c0c0 75deg,
            #808080 80deg, #c0c0c0 85deg, #a0a0a0 90deg, #c0c0c0 95deg,
            #808080 100deg, #c0c0c0 105deg, #a0a0a0 110deg, #c0c0c0 115deg,
            #808080 120deg, #c0c0c0 125deg, #a0a0a0 130deg, #c0c0c0 135deg,
            #808080 140deg, #c0c0c0 145deg, #a0a0a0 150deg, #c0c0c0 155deg,
            #808080 160deg, #c0c0c0 165deg, #a0a0a0 170deg, #c0c0c0 175deg,
            #808080 180deg, #c0c0c0 185deg, #a0a0a0 190deg, #c0c0c0 195deg,
            #808080 200deg, #c0c0c0 205deg, #a0a0a0 210deg, #c0c0c0 215deg,
            #808080 220deg, #c0c0c0 225deg, #a0a0a0 230deg, #c0c0c0 235deg,
            #808080 240deg, #c0c0c0 245deg, #a0a0a0 250deg, #c0c0c0 255deg,
            #808080 260deg, #c0c0c0 265deg, #a0a0a0 270deg, #c0c0c0 275deg,
            #808080 280deg, #c0c0c0 285deg, #a0a0a0 290deg, #c0c0c0 295deg,
            #808080 300deg, #c0c0c0 305deg, #a0a0a0 310deg, #c0c0c0 315deg,
            #808080 320deg, #c0c0c0 325deg, #a0a0a0 330deg, #c0c0c0 335deg,
            #808080 340deg, #c0c0c0 345deg, #a0a0a0 350deg, #c0c0c0 355deg,
            #808080 360deg
        );
    border: 3px solid #606060;
    box-shadow:
        inset 0 0 12px rgba(0,0,0,0.25),
        inset 0 0 40px rgba(0,0,0,0.08),
        0 0 0 1px rgba(96,96,96,0.6),
        0 0 0 4px rgba(128,128,128,0.35),
        0 0 0 7px rgba(96,96,96,0.2);
}

/* Coin inner decorative ring */
.coin-inner-ring {
    position: absolute;
    width: 160px;
    height: 160px;
    border-radius: 50%;
    border: 2px solid rgba(139,105,20,0.5);
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    pointer-events: none;
    backface-visibility: hidden;
}

.coin-tails .coin-inner-ring {
    border-color: rgba(96,96,96,0.5);
}

/* Coin center decoration — star/cross */
.coin-center-decor {
    position: absolute;
    width: 60px;
    height: 60px;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    pointer-events: none;
    backface-visibility: hidden;
}

.coin-decor-arm {
    position: absolute;
    background: rgba(139,105,20,0.2);
    border-radius: 2px;
}

.coin-tails .coin-decor-arm {
    background: rgba(96,96,96,0.25);
}

.coin-decor-arm-h {
    width: 100%;
    height: 16px;
    top: 50%;
    left: 0;
    transform: translateY(-50%);
}

.coin-decor-arm-v {
    width: 16px;
    height: 100%;
    left: 50%;
    top: 0;
    transform: translateX(-50%);
}

.coin-decor-arm-d1 {
    width: 14px;
    height: 50%;
    top: 50%;
    left: 0;
    transform: rotate(45deg);
    transform-origin: top left;
}

.coin-decor-arm-d2 {
    width: 14px;
    height: 50%;
    top: 50%;
    right: 0;
    transform: rotate(-45deg);
    transform-origin: top right;
}

/* Coin symbol (H/T) */
.coin-symbol {
    position: relative;
    z-index: 2;
    font-size: 56px;
    font-family: 'Georgia', 'Times New Roman', serif;
    font-weight: 700;
    text-shadow: 0 2px 6px rgba(0,0,0,0.4), 0 -1px 1px rgba(255,255,255,0.15);
    user-select: none;
    backface-visibility: hidden;
    pointer-events: none;
}

.coin-heads .coin-symbol {
    color: #fff8dc;
}

.coin-tails .coin-symbol {
    color: #f0f0f0;
}

/* ===== Coin Edge Slices (3D Cylinder Approximation) ===== */
.coin-edge-slice {
    position: absolute;
    left: 50%;
    top: 50%;
    height: 12px;
    background: linear-gradient(
        to right,
        #daa520 0%,
        #ffd700 20%,
        #8b6914 50%,
        #ffd700 80%,
        #daa520 100%
    );
    transform-origin: center center;
    backface-visibility: visible;
}

.coin-edge-slice.silver-edge {
    background: linear-gradient(
        to right,
        #909090 0%,
        #c0c0c0 20%,
        #606060 50%,
        #c0c0c0 80%,
        #909090 100%
    );
}

/* ===== Coin Outer Glow ===== */
.coin-scene::before {
    content: '';
    position: absolute;
    width: 200px;
    height: 200px;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(173,198,255,0.15) 0%, transparent 70%);
    pointer-events: none;
    z-index: -1;
}

/* ===== Flip button pulse ===== */
@keyframes flipPulse {
    0%, 100% { box-shadow: 0 0 10px rgba(173, 198, 255, 0.3); }
    50% { box-shadow: 0 0 25px rgba(0, 241, 254, 0.5); }
}

.btn-flip {
    animation: flipPulse 2s ease-in-out infinite;
}

.btn-flip:disabled {
    animation: none;
    opacity: 0.5;
    cursor: not-allowed;
}

/* ===== Collapsible Navigation ===== */
.collapse-nav {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.35s cubic-bezier(0.4, 0, 0.2, 1);
}

.collapse-nav.open {
    max-height: 300px;
}

.collapse-trigger {
    cursor: pointer;
    user-select: none;
}

.collapse-arrow {
    transition: transform 0.3s ease;
    display: inline-block;
}

.collapse-arrow.open {
    transform: rotate(180deg);
}

/* ===== Result Flash ===== */
@keyframes resultFlash {
    0% { opacity: 0; transform: translateY(10px); }
    100% { opacity: 1; transform: translateY(0); }
}

.result-text {
    animation: resultFlash 0.5s ease-out;
}

/* ===== Counter Number Animation ===== */
@keyframes countUp {
    0% { transform: translateY(-10px); opacity: 0; }
    100% { transform: translateY(0); opacity: 1; }
}

.counter-updated {
    animation: countUp 0.4s ease-out;
}

/* ===== Mobile Adjustments ===== */
@media (max-width: 640px) {
    .coin-scene {
        width: 160px;
        height: 160px;
    }

    .coin-face {
        width: 160px;
        height: 160px;
    }

    .coin-inner-ring {
        width: 128px;
        height: 128px;
    }

    .coin-symbol {
        font-size: 44px;
    }

    .coin-center-decor {
        width: 48px;
        height: 48px;
    }

    .coin-scene::before {
        width: 160px;
        height: 160px;
    }
}