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

:root {
    --red:    #ff2d55;
    --blue:   #0a84ff;
    --green:  #30d158;
    --yellow: #ffd60a;
    --bg:     #0a0a0f;
    --surface: #13131a;
    --border: #2a2a3a;
    --text:   #e0e0ff;
    --muted:  #555577;
}

body {
    background-color: var(--bg);
    color: var(--text);
    font-family: 'Orbitron', sans-serif;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: space-between;
    overflow: hidden;
    user-select: none;
}

/* Live canvas background */
#bg-canvas {
    position: fixed;
    inset: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
}

header {
    padding: 2rem 0 0.5rem;
    z-index: 1;
}

header h1 {
    font-size: clamp(1.8rem, 5vw, 3rem);
    font-weight: 900;
    letter-spacing: 0.3em;
    color: #fff;
    text-shadow: 0 0 30px rgba(255,255,255,0.15);
}

header h1 span {
    color: var(--yellow);
    text-shadow: 0 0 20px rgba(255,214,10,0.5);
}

/* Status bar */
.status-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: min(420px, 90vw);
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 50px;
    padding: 0.6rem 1.5rem;
    z-index: 1;
    gap: 1rem;
}

.score-box {
    display: flex;
    flex-direction: column;
    align-items: center;
    min-width: 48px;
}

.score-box .label {
    font-size: 0.5rem;
    letter-spacing: 0.15em;
    color: var(--muted);
}

.score-box span:last-child {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--yellow);
    line-height: 1;
    transition: transform 0.2s;
}

#message {
    font-size: clamp(0.55rem, 2vw, 0.75rem);
    letter-spacing: 0.08em;
    color: var(--text);
    text-align: center;
    flex: 1;
    transition: color 0.3s;
}

/* Game board */
.game-wrapper {
    position: relative;
    width: min(380px, 88vw);
    height: min(380px, 88vw);
    z-index: 1;
}

.btn-container {
    width: 100%;
    height: 100%;
    display: grid;
    grid-template-columns: 1fr 1fr;
    grid-template-rows: 1fr 1fr;
    gap: 10px;
    border-radius: 50%;
    overflow: hidden;
    box-shadow:
        0 0 0 8px var(--surface),
        0 0 0 10px var(--border),
        0 30px 80px rgba(0,0,0,0.8);
}

.btn {
    cursor: pointer;
    transition: filter 0.15s, transform 0.15s;
    position: relative;
    overflow: hidden;
}

.btn::after {
    content: '';
    position: absolute;
    inset: 0;
    background: rgba(255,255,255,0.08);
    opacity: 0;
    transition: opacity 0.15s;
}

.btn:hover::after { opacity: 1; }

.red    { background: #5c1020; border-radius: 100% 0 0 0; }
.blue   { background: #041e3a; border-radius: 0 100% 0 0; }
.green  { background: #0a2e14; border-radius: 0 0 0 100%; }
.yellow { background: #2e2200; border-radius: 0 0 100% 0; }

/* Active flash — game sequence */
.btn.flash.red    { background: var(--red);    box-shadow: 0 0 60px var(--red),    inset 0 0 40px rgba(255,255,255,0.3); filter: brightness(1.4); }
.btn.flash.blue   { background: var(--blue);   box-shadow: 0 0 60px var(--blue),   inset 0 0 40px rgba(255,255,255,0.3); filter: brightness(1.4); }
.btn.flash.green  { background: var(--green);  box-shadow: 0 0 60px var(--green),  inset 0 0 40px rgba(255,255,255,0.3); filter: brightness(1.4); }
.btn.flash.yellow { background: var(--yellow); box-shadow: 0 0 60px var(--yellow), inset 0 0 40px rgba(255,255,255,0.3); filter: brightness(1.4); }

/* User press flash */
.btn.userflash.red    { background: var(--red);    filter: brightness(1.2); transform: scale(0.97); }
.btn.userflash.blue   { background: var(--blue);   filter: brightness(1.2); transform: scale(0.97); }
.btn.userflash.green  { background: var(--green);  filter: brightness(1.2); transform: scale(0.97); }
.btn.userflash.yellow { background: var(--yellow); filter: brightness(1.2); transform: scale(0.97); }

/* Center logo */
.center-logo {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 80px;
    height: 80px;
    background: var(--bg);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.8rem;
    font-weight: 900;
    color: #fff;
    z-index: 2;
    box-shadow: 0 0 0 4px var(--border), 0 0 30px rgba(0,0,0,0.9);
}

.logo-ring {
    position: absolute;
    inset: -4px;
    border-radius: 50%;
    border: 2px solid transparent;
    background: conic-gradient(var(--red), var(--blue), var(--green), var(--yellow), var(--red)) border-box;
    -webkit-mask: linear-gradient(#fff 0 0) padding-box, linear-gradient(#fff 0 0);
    -webkit-mask-composite: destination-out;
    mask-composite: exclude;
    animation: spin 4s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Game over shake */
@keyframes shake {
    0%,100% { transform: translateX(0); }
    20%      { transform: translateX(-12px); }
    40%      { transform: translateX(12px); }
    60%      { transform: translateX(-8px); }
    80%      { transform: translateX(8px); }
}

.game-wrapper.shake {
    animation: shake 0.5s ease;
}

/* Level up pulse on score */
@keyframes pop {
    0%   { transform: scale(1); }
    50%  { transform: scale(1.4); }
    100% { transform: scale(1); }
}

.pop { animation: pop 0.3s ease; }

/* Footer */
footer {
    padding: 1rem 0 1.5rem;
    font-size: 0.65rem;
    letter-spacing: 0.12em;
    color: var(--muted);
    z-index: 1;
}

footer strong { color: var(--text); }

.heart {
    color: var(--red);
    display: inline-block;
    animation: heartbeat 1.4s ease infinite;
}

@keyframes heartbeat {
    0%,100% { transform: scale(1); }
    14%     { transform: scale(1.3); }
    28%     { transform: scale(1); }
    42%     { transform: scale(1.2); }
    56%     { transform: scale(1); }
}

/* Disabled state during sequence playback */
body.playing .btn { pointer-events: none; }