/* assets/css/base.css */
:root {
    --bg-gradient-start: #222222;
    --bg-gradient-end: #444444;
    --image-bg-opacity: 0.75;
    --blur-strength: 0;
    --text-color: #e0e0e0;
    --text-secondary-color: #a0a0a0;
    --accent-color: #00aaff;
    --accent-rgb: 0, 170, 255;
    --border-color: rgba(60, 60, 60, 0.7);
    --sidebar-bg-color: #000000;
    --sidebar-bg-color-rgb: 0, 0, 0;
    --sidebar-bg-opacity: 0.1;
    --sidebar-text-color: #c0c0c0;
    --sidebar-nav-hover-bg-color: rgba(0, 170, 255, 0.1);
    --sidebar-nav-active-text-color: #e0e0e0;
    --search-bg-opacity: 0.1;
    --search-text-color: #c0c0c0;
    --search-placeholder-color: #c0c0c0;
    --search-icon-color: #e0e0e0;
    --search-shadow-focus: 0 0 15px rgba(0, 170, 255, 0.3);
    --dropdown-bg-opacity: 0.9;
    --dropdown-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
    --autocomplete-bg-opacity: 0.9;
    --autocomplete-odd-bg: rgba(45, 60, 80, 0.4);
    --autocomplete-even-bg: rgba(35, 50, 70, 0.4);
    --autocomplete-hover-bg: #00aaff;
    --autocomplete-hover-text-color: #ffffff;
    --card-bg-color: #000000;
    --card-bg-color-rgb: 0, 0, 0;
    --card-bg-opacity: 0.2;
    --card-shadow: none;
    --card-shadow-hover: 0 10px 20px rgba(0,0,0,0.19), 0 6px 6px rgba(0,0,0,0.23);
    --max-columns: 4;
    --text-stroke-enabled: 1;
    --text-stroke-width: 0.2px;
    --text-color-inverted: #1f1f1f;
    --background-image-transition-duration: 0.5s;
}

@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes gradientShift {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

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

body {
    font-family: 'Segoe UI', 'Microsoft YaHei', Arial, sans-serif;
    color: var(--text-color);
    display: flex;
    overflow-x: hidden;
    min-height: 100vh;
    position: relative;
    background-color: #000;
    -webkit-text-stroke: calc(var(--text-stroke-enabled) * var(--text-stroke-width)) var(--text-color-inverted);
    text-stroke: calc(var(--text-stroke-enabled) * var(--text-stroke-width)) var(--text-color-inverted);
}

body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    background-image: linear-gradient(-45deg, var(--bg-gradient-start), var(--bg-gradient-end));
    background-size: 400% 400%;
    animation: gradientShift 15s ease infinite;
    z-index: -2;
}

#background-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    pointer-events: none;
}

#background-container img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0;
    transition: opacity var(--background-image-transition-duration) ease;
}

#background-container img.loaded {
    opacity: var(--image-bg-opacity);
}

.fallback-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    height: 100%;
    border-radius: inherit;
    background-color: rgba(255, 255, 255, 0.15);
    color: var(--text-color);
    font-size: 0.8em;
    font-weight: bold;
    text-transform: uppercase;
}