:root {
    --neon-blue: #00f2ff;
    --neon-glow: rgba(0, 242, 255, 0.5);
    --bg-dark: rgba(10, 10, 15, 0.85);
    --glass-bg: rgba(255, 255, 255, 0.05);
    --font-main: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-font-smoothing: antialiased;
}

body {
    background-color: #000;
    color: #fff;
    font-family: var(--font-main);
    overflow: hidden;
    width: 100vw;
    height: 100vh;
}

/* HUD Canvas - 전체 화면 고정 */
#hud-canvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
}

/* UI Layer - 설정 창 등 */
#ui-layer {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 10;
    display: flex;
    justify-content: center;
    align-items: center;
    pointer-events: auto;
    transition: opacity 0.5s ease;
}

.settings-panel {
    background: var(--bg-dark);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(0, 242, 255, 0.3);
    border-radius: 16px;
    padding: 2rem;
    width: 450px;
    box-shadow: 0 0 40px rgba(0, 0, 0, 0.5), 0 0 20px var(--neon-glow);
}

h1 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--neon-blue);
    text-transform: uppercase;
    letter-spacing: 2px;
    text-align: center;
}

.instruction {
    font-size: 0.9rem;
    color: #aaa;
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

button {
    width: 100%;
    padding: 12px;
    background: transparent;
    border: 1px solid var(--neon-blue);
    color: var(--neon-blue);
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    text-transform: uppercase;
    transition: all 0.3s ease;
    margin-bottom: 10px;
}

button:hover {
    background: var(--neon-blue);
    color: #000;
    box-shadow: 0 0 20px var(--neon-blue);
}

button.primary {
    background: var(--neon-blue);
    color: #000;
}

/* HUD Overlay Layer - 마우스 클릭 무시 */
#overlay-layer {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 5;
    pointer-events: none; /* 클릭 통과 핵심 */
    display: none;
}

.hud-frame {
    position: absolute;
    border: 2px solid var(--neon-blue);
    box-shadow: inset 0 0 20px var(--neon-glow), 0 0 20px var(--neon-glow);
    transition: all 0.5s ease;
}

/* 애니메이션 효과 */
@keyframes scanline {
    0% { transform: translateY(-100%); }
    100% { transform: translateY(100%); }
}

.scanline {
    width: 100%;
    height: 2px;
    background: var(--neon-blue);
    opacity: 0.3;
    position: absolute;
    animation: scanline 4s linear infinite;
}

/* 영역 선택 가이드 */
#selection-guide {
    position: absolute;
    border: 2px dashed var(--neon-blue);
    background: rgba(0, 242, 255, 0.1);
    display: none;
    z-index: 20;
}