:root {
    --color-page: #050607;
    --color-text: #f4f7fb;
    --color-muted: #aebbc5;
    --color-panel: rgba(7, 11, 14, 0.45);
    --color-panel-hover: rgba(19, 32, 39, 0.58);
    --color-panel-border: rgba(190, 218, 228, 0.24);
    --color-panel-divider: rgba(190, 218, 228, 0.18);
    --color-panel-shadow: rgba(0, 0, 0, 0.28);
    --color-control: rgba(19, 32, 39, 0.58);
    --color-control-hover: rgba(24, 45, 62, 0.66);
    --color-control-border: rgba(176, 209, 224, 0.34);
    --color-control-strong-border: rgba(180, 224, 255, 0.52);
    --color-control-disabled: rgba(18, 22, 25, 0.8);
    --color-text-disabled: #77838c;
    --color-progress-track: rgba(255, 255, 255, 0.1);
    --color-progress-fill: #65d6a5;
    --color-level-ready-border: #ffd45c;
    --color-start-button: rgba(38, 170, 218, 0.18);
    --color-start-button-hover: rgba(38, 170, 218, 0.3);
    --color-start-button-border: rgba(120, 220, 255, 0.74);
    --color-start-button-shadow: rgba(38, 170, 218, 0.26);
}

:root[data-theme="light"] {
    --color-page: #e7edf0;
    --color-text: #102027;
    --color-muted: #50626b;
    --color-panel: rgba(248, 252, 253, 0.62);
    --color-panel-hover: rgba(229, 241, 246, 0.72);
    --color-panel-border: rgba(76, 104, 116, 0.24);
    --color-panel-divider: rgba(76, 104, 116, 0.18);
    --color-panel-shadow: rgba(46, 66, 75, 0.18);
    --color-control: rgba(255, 255, 255, 0.62);
    --color-control-hover: rgba(229, 241, 246, 0.72);
    --color-control-border: rgba(55, 88, 104, 0.28);
    --color-control-strong-border: rgba(36, 116, 154, 0.4);
    --color-control-disabled: rgba(220, 228, 232, 0.86);
    --color-text-disabled: #78878e;
    --color-progress-track: rgba(16, 32, 39, 0.12);
    --color-progress-fill: #209866;
    --color-level-ready-border: #d58a00;
    --color-start-button: rgba(22, 136, 190, 0.22);
    --color-start-button-hover: rgba(22, 136, 190, 0.34);
    --color-start-button-border: rgba(17, 122, 184, 0.58);
    --color-start-button-shadow: rgba(22, 136, 190, 0.2);
}

@media (prefers-color-scheme: light) {
    :root:not([data-theme]) {
        --color-page: #e7edf0;
        --color-text: #102027;
        --color-muted: #50626b;
        --color-panel: rgba(248, 252, 253, 0.62);
        --color-panel-hover: rgba(229, 241, 246, 0.72);
        --color-panel-border: rgba(76, 104, 116, 0.24);
        --color-panel-divider: rgba(76, 104, 116, 0.18);
        --color-panel-shadow: rgba(46, 66, 75, 0.18);
        --color-control: rgba(255, 255, 255, 0.62);
        --color-control-hover: rgba(229, 241, 246, 0.72);
        --color-control-border: rgba(55, 88, 104, 0.28);
        --color-control-strong-border: rgba(36, 116, 154, 0.4);
        --color-control-disabled: rgba(220, 228, 232, 0.86);
        --color-text-disabled: #78878e;
        --color-progress-track: rgba(16, 32, 39, 0.12);
        --color-progress-fill: #209866;
        --color-level-ready-border: #d58a00;
        --color-start-button: rgba(22, 136, 190, 0.22);
        --color-start-button-hover: rgba(22, 136, 190, 0.34);
        --color-start-button-border: rgba(17, 122, 184, 0.58);
        --color-start-button-shadow: rgba(22, 136, 190, 0.2);
    }
}

body, html {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    background-color: var(--color-page);
    position: relative;
    color: var(--color-text);
    font-family: Arial, sans-serif;
}

#game-canvas {
    display: block;
    width: 100%;
    height: 100%;
}

#welcome-screen {
    position: absolute;
    inset: 0;
    z-index: 12;
    display: flex;
    align-items: flex-end;
    justify-content: center;
    padding-bottom: clamp(72px, 18vh, 190px);
    box-sizing: border-box;
    pointer-events: none;
    opacity: 1;
    transition: opacity 180ms ease, visibility 180ms ease;
}

#start-button {
    min-width: min(340px, calc(100vw - 48px));
    min-height: 72px;
    padding: 0 26px;
    border: 1px solid var(--color-start-button-border);
    border-radius: 6px;
    background: var(--color-start-button);
    color: var(--color-text);
    box-shadow: 0 18px 38px var(--color-panel-shadow), 0 0 24px var(--color-start-button-shadow);
    backdrop-filter: blur(2px);
    cursor: pointer;
    font: inherit;
    font-size: 22px;
    font-weight: 700;
    letter-spacing: 0;
    pointer-events: auto;
    animation: start-button-float 2800ms ease-in-out infinite;
}

#start-button:hover {
    background: var(--color-start-button-hover);
}

@keyframes start-button-float {
    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-8px);
    }
}

#theme-controls {
    position: absolute;
    top: 16px;
    right: 20px;
    z-index: 10;
    display: flex;
    gap: 8px;
}

.icon-button {
    display: grid;
    place-items: center;
    width: 42px;
    height: 42px;
    padding: 0;
    background-color: var(--color-panel);
    color: var(--color-text);
    border: 1px solid var(--color-control-strong-border);
    border-radius: 4px;
    backdrop-filter: blur(1px);
    cursor: pointer;
}

.icon-button:hover {
    background-color: var(--color-panel-hover);
}

.icon-button svg {
    width: 20px;
    height: 20px;
    fill: none;
    stroke: currentColor;
    stroke-width: 1.8;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.icon-button circle {
    fill: none;
}

.theme-icon {
    display: none;
}

:root[data-theme-preference="system"] .theme-icon-system,
:root[data-theme-preference="light"] .theme-icon-light,
:root[data-theme-preference="dark"] .theme-icon-dark {
    display: block;
}

#side-panel,
#tech-panel {
    position: absolute;
    z-index: 10;
    background: var(--color-panel);
    border: 1px solid var(--color-panel-border);
    box-shadow: 0 12px 28px var(--color-panel-shadow);
    backdrop-filter: blur(1px);
}

#hud,
#side-panel,
#center-button {
    opacity: 1;
    transition: opacity 220ms ease, visibility 220ms ease;
}

.pre-start #hud,
.pre-start #side-panel,
.pre-start #center-button {
    visibility: hidden;
    opacity: 0;
    pointer-events: none;
}

.game-started #welcome-screen {
    visibility: hidden;
    opacity: 0;
}

#hud {
    position: absolute;
    bottom: 20px;
    left: 50%;
    z-index: 10;
    transform: translateX(-50%);
    pointer-events: none;
}

.label,
.hud-panel small,
#side-panel small,
#tile-details {
    color: var(--color-muted);
}

.label {
    display: block;
    font-size: 11px;
    text-transform: uppercase;
}

.hud-panel {
    position: static;
    min-width: 104px;
    background: var(--color-panel);
    border: 1px solid var(--color-panel-border);
    border-radius: 6px;
    box-shadow: 0 12px 28px var(--color-panel-shadow);
    padding: 10px 12px;
    box-sizing: border-box;
    backdrop-filter: blur(1px);
    pointer-events: auto;
}

.status-panel {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 48px;
    align-items: center;
    gap: 12px;
    width: auto;
}

.status-metrics {
    display: grid;
    grid-template-columns: 104px 116px 190px;
    align-items: center;
    gap: 12px;
}

.resource-counter {
    display: flex;
    align-items: center;
    gap: 10px;
    min-width: 0;
}

.resource-value {
    min-width: 0;
}

.progress-content {
    min-width: 0;
}

.hud-panel strong {
    display: block;
    margin-top: 0;
    font-size: 20px;
    line-height: 1.1;
}

.hud-panel small {
    display: block;
    margin-top: 2px;
    font-size: 12px;
}

.progress-header {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 12px;
}

.progress-header small {
    min-width: 0;
    margin-top: 0;
}

.progress-header strong {
    flex: 0 0 auto;
    margin-top: 0;
    text-align: right;
}

.resource-glyph {
    flex: 0 0 auto;
    width: 30px;
    height: 30px;
    fill: none;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.energy-glyph {
    fill: var(--color-text);
    stroke: none;
    stroke-width: 1.4;
}

.research-glyph {
    color: var(--color-text);
    stroke: currentColor;
    stroke-width: 1.75;
}

.research-glyph circle {
    fill: currentColor;
}

.xp-track {
    height: 5px;
    margin-top: 7px;
    overflow: hidden;
    background: var(--color-progress-track);
    border-radius: 999px;
}

#xp-fill {
    width: 0%;
    height: 100%;
    background: var(--color-progress-fill);
}

#side-panel {
    top: 16px;
    left: 16px;
    width: 220px;
    border-radius: 6px;
    padding: 9px;
    transition: opacity 160ms ease, visibility 160ms ease, transform 120ms ease;
}

#selected-panel {
    min-height: 0;
}

#tile-title,
#tech-panel h2 {
    margin: 0;
    font-size: 14px;
    letter-spacing: 0;
}

#tile-details {
    min-height: 0;
    margin: 5px 0 8px;
    font-size: 12px;
    line-height: 1.35;
}

#tile-action,
.tech-button,
#resume-run {
    width: 100%;
    min-height: 32px;
    border: 1px solid var(--color-control-border);
    border-radius: 4px;
    background: var(--color-control);
    color: var(--color-text);
    cursor: pointer;
}

#tile-action:disabled,
.tech-button:disabled {
    color: var(--color-text-disabled);
    cursor: default;
    background: var(--color-control-disabled);
}

.hud-button {
    position: static;
    display: grid;
    place-items: center;
    width: 64px;
    height: 64px;
    padding: 0;
    background: var(--color-panel);
    color: var(--color-text);
    border: 1px solid var(--color-control-strong-border);
    border-radius: 6px;
    box-shadow: 0 12px 28px var(--color-panel-shadow);
    backdrop-filter: blur(1px);
    cursor: pointer;
    pointer-events: auto;
}

.status-panel .home-button {
    flex: 0 0 auto;
    width: 48px;
    height: 48px;
    box-shadow: none;
}

.status-panel .home-button svg {
    width: 30px;
    height: 30px;
}

.home-button.level-ready {
    background: rgba(255, 196, 66, 0.2);
    border-color: var(--color-level-ready-border, #ffd45c);
    animation: core-level-ready-glow 1200ms ease-in-out infinite;
}

.home-button.level-ready:hover {
    background: rgba(255, 196, 66, 0.3);
}

@keyframes core-level-ready-glow {
    0%,
    100% {
        box-shadow: 0 0 0 0 rgba(255, 212, 92, 0.18), 0 0 12px rgba(255, 196, 66, 0.28);
    }

    50% {
        box-shadow: 0 0 0 5px rgba(255, 212, 92, 0.16), 0 0 24px rgba(255, 196, 66, 0.56);
    }
}

.hud-button:hover {
    background: var(--color-panel-hover);
}

.hud-button svg {
    width: 36px;
    height: 36px;
    fill: none;
    stroke: currentColor;
    stroke-width: 1.7;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.home-button .core-top {
    fill: #7de6ff;
    stroke: none;
}

.home-button .core-right {
    fill: #168fc5;
    stroke: none;
}

.home-button .core-left {
    fill: #32b6e6;
    stroke: none;
}

.home-button .core-line {
    fill: none;
    stroke: rgba(230, 250, 255, 0.92);
    stroke-width: 1.4;
}

#tech-overlay {
    position: absolute;
    inset: 0;
    z-index: 14;
    display: grid;
    place-items: center;
    padding: 20px;
    box-sizing: border-box;
    background: rgba(0, 0, 0, 0.24);
    pointer-events: auto;
}

#tech-overlay[hidden] {
    display: none;
}

#tech-panel {
    position: static;
    width: min(520px, calc(100vw - 40px));
    border-radius: 6px;
    padding: 16px;
}

.tech-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 16px;
}

#tech-points {
    flex: 0 0 auto;
    font-size: 18px;
}

#tech-award {
    margin: 10px 0 14px;
    color: var(--color-muted);
    font-size: 13px;
    line-height: 1.45;
}

.tech-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 10px;
}

.tech-button {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    padding: 10px;
    text-align: left;
}

#resume-run {
    margin-top: 12px;
}

@media (max-width: 760px) {
    #hud {
        bottom: 16px;
        left: 50%;
        width: calc(100vw - 20px);
        max-width: max-content;
    }

    #side-panel {
        top: 10px;
        left: 10px;
        bottom: auto;
        width: min(280px, calc(100vw - 62px));
        padding: 10px;
        transform: none;
    }

    #theme-controls {
        top: 10px;
        right: 10px;
    }

    .hud-button {
        width: 54px;
        height: 54px;
    }

    .hud-button svg {
        width: 30px;
        height: 30px;
    }

    .status-panel {
        grid-template-columns: minmax(0, 1fr) 48px;
        width: 100%;
    }

    .status-metrics {
        grid-template-columns: minmax(82px, 1fr) minmax(94px, 1fr) minmax(128px, 1.2fr);
        gap: 8px;
    }

    .hud-panel {
        padding: 8px 9px;
    }

    .tech-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 560px) {
    .status-metrics {
        grid-template-columns: minmax(82px, 1fr) minmax(94px, 1fr);
    }

    .progress-content {
        grid-column: 1 / -1;
    }
}

@media (max-width: 360px) {
    .hud-button {
        width: 50px;
        height: 50px;
    }

    .status-metrics {
        grid-template-columns: minmax(74px, 1fr) minmax(84px, 1fr);
    }

    .resource-glyph {
        width: 26px;
        height: 26px;
    }

}