:root {
    --bunker-gray: #2B2B2B;
    --amber-orange: #FFBF00;
    --oxygen-blue: #00FFFF;
    --tungsten-silver: #C0C0C0;
    --deep-black: #1A1A1A;
    --concrete-gray: #4A4A4A;
}

body {
    background-color: var(--bunker-gray);
    color: var(--tungsten-silver);
    font-family: 'Inter', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    overflow-x: hidden;
    margin: 0;
    padding: 0;
}

/* 工業與軍用字體風格 */
h1, h2, h3, .nav-link, .btn {
    font-family: 'Oswald', 'Impact', sans-serif;
    text-transform: uppercase;
    letter-spacing: 2px;
}

.mono-font {
    font-family: 'Courier New', Courier, monospace;
}

/* 重型機械感背景與邊框 */
.bunker-panel {
    background: linear-gradient(145deg, #252525, #323232);
    border: 2px solid var(--concrete-gray);
    box-shadow: inset 2px 2px 5px rgba(0,0,0,0.5), 5px 5px 15px rgba(0,0,0,0.8);
    padding: 20px;
    position: relative;
    overflow: hidden;
}

.bunker-panel::before {
    content: "";
    position: absolute;
    top: 0; left: 0; right: 0; height: 2px;
    background: var(--tungsten-silver);
    opacity: 0.1;
}

/* 琥珀橙強調色 */
.text-amber { color: var(--amber-orange); }
.bg-amber { background-color: var(--amber-orange); }
.border-amber { border-color: var(--amber-orange) !important; }

/* 氧氣藍強調色 */
.text-oxygen { color: var(--oxygen-blue); }
.bg-oxygen { background-color: var(--oxygen-blue); }

/* 導覽列樣式 */
.navbar {
    background-color: var(--deep-black) !important;
    border-bottom: 3px solid var(--amber-orange);
    padding: 1rem 2rem;
}

.navbar-brand {
    color: var(--amber-orange) !important;
    font-weight: bold;
    font-size: 1.5rem;
    text-shadow: 0 0 10px rgba(255, 191, 0, 0.5);
}

.nav-link {
    color: var(--tungsten-silver) !important;
    margin: 0 10px;
    transition: all 0.3s;
}

.nav-link:hover, .nav-link.active {
    color: var(--amber-orange) !important;
    text-shadow: 0 0 5px var(--amber-orange);
}

/* 重型按鈕效果 */
.btn-heavy {
    background: var(--concrete-gray);
    color: white;
    border: 3px solid var(--tungsten-silver);
    border-radius: 0;
    padding: 10px 25px;
    transition: all 0.1s;
    position: relative;
    overflow: hidden;
}

.btn-heavy:active {
    transform: translateY(2px);
    box-shadow: none;
    background: #333;
}

.btn-heavy::after {
    content: "";
    position: absolute;
    top: 0; left: -100%;
    width: 100%; height: 100%;
    background: rgba(255,255,255,0.1);
    transition: 0.3s;
}

.btn-heavy:hover::after {
    left: 0;
}

/* 閃爍動畫 */
@keyframes blink-amber {
    0% { opacity: 1; }
    50% { opacity: 0.3; }
    100% { opacity: 1; }
}

.blink-warning {
    animation: blink-amber 1s infinite;
}

/* 掃描線效果 */
.scanline {
    width: 100%;
    height: 2px;
    background: rgba(0, 255, 255, 0.2);
    position: absolute;
    z-index: 10;
    top: 0;
    animation: scan 4s linear infinite;
}

@keyframes scan {
    0% { top: 0; }
    100% { top: 100%; }
}

/* 雷達樣式預設 */
.radar-container {
    width: 300px;
    height: 300px;
    border-radius: 50%;
    border: 2px solid var(--oxygen-blue);
    position: relative;
    background: radial-gradient(circle, rgba(0,255,255,0.1) 0%, rgba(0,0,0,1) 80%);
    margin: 0 auto;
}

.radar-sweep {
    width: 150px;
    height: 150px;
    background: linear-gradient(45deg, rgba(0,255,255,0.4) 0%, transparent 50%);
    position: absolute;
    top: 0; left: 0;
    transform-origin: bottom right;
    animation: sweep 4s linear infinite;
}

@keyframes sweep {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

/* 地底深度計模擬 */
.depth-meter {
    position: fixed;
    right: 20px;
    bottom: 20px;
    font-size: 0.8rem;
    color: var(--oxygen-blue);
    opacity: 0.6;
    text-align: right;
    z-index: 1000;
}