/* ===== Root palette ===== */
:root {
    --bg: #000;
    --panel: #111;
    --text: #ff3a3a;
    --accent: #ff5555;
    --accent-light: #ff8888;
    --btn-bg: #222;
    --btn-hover: #331010;
    --progress-bg: #222;
    --progress-fill: #ff0000;
    --shadow: 0 0 15px rgba(255, 0, 0, .5);
    --radius: 14px;
}

/* ===== Reset & base ===== */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0
}

body {
    background: var(--bg);
    color: var(--text);
    font-family: Arial, Helvetica, sans-serif;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    overflow-x: hidden;
}

/* ===== Header & footer ===== */
header, footer {
    background: darkred;
    color: #fff;
    text-align: center;
    padding: 1em;
}

footer {
    margin-top: auto
}

/* Footer */
#footer-placeholder footer {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    background: darkred;
    color: #fff;
    text-align: center;
    padding: 1em 0;
    z-index: 3;
}

/* ===== Layout ===== */
main {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
    padding: 20px 10px 140px; /* bottom pad so content above fixed footer */
}

/* ===== Reactor core ===== */
#reactor {
    width: 280px;
    height: 280px;
    border-radius: 50%;
    background: radial-gradient(circle at center,
    var(--accent-light) 0%, var(--accent) 40%, #5a0000 60%, #330000 100%);
    box-shadow: var(--shadow), inset 0 0 25px #000;
    position: relative;
    transition: filter .2s;
}

#temperature {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 2.4rem;
    font-weight: 700;
    color: #fff;
    text-shadow: 0 0 6px #000;
}

/* ===== Progress bar ===== */
.progress-wrap {
    width: 320px;
    height: 28px;
    background: var(--progress-bg);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
}

#progress {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, #ff8800, #ff0000);
}

/* ===== Buttons ===== */
.controls, .upgrades {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 12px;
    max-width: 600px;
}

button {
    flex: 1 1 130px;
    padding: 14px;
    background: var(--btn-bg);
    color: var(--text);
    border: 2px solid var(--accent);
    border-radius: var(--radius);
    font-weight: 700;
    cursor: pointer;
    box-shadow: var(--shadow);
    transition: background .2s, border-color .2s, transform .1s;
}

button:hover {
    background: var(--btn-hover)
}

button:active {
    transform: scale(.95)
}

button[disabled] {
    opacity: .3;
    cursor: not-allowed
}

h2 {
    margin-top: 10px;
    text-align: center;
    color: var(--accent-light)
}

#credits {
    font-weight: 700;
    font-size: 1.1rem
}

.flash {
    animation: flash .15s alternate 3
}

@keyframes flash {
    from {
        filter: brightness(2)
    }
    to {
        filter: brightness(.5)
    }
}

/* ===== Mobile tweaks ===== */
@media (max-width: 500px) {
    #reactor {
        width: 200px;
        height: 200px
    }

    #temperature {
        font-size: 2rem
    }

    .progress-wrap {
        width: 260px
    }
}
[data-theme="light"] body{background-color:#f0f5fa!important;color:#1f2937!important}[data-theme="light"] .game-container,[data-theme="light"] .controls,[data-theme="light"] .score{background-color:#ffffff!important;color:#1f2937!important;border-color:#d1d5db!important}[data-theme="light"] button{background-color:#2563eb!important;color:#fff!important}[data-theme="light"] button:hover{background-color:#1d4ed8!important}