:root {
    --bg-dark: #0f172a;
    --bg-darker: #020617;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --glass-bg: rgba(30, 41, 59, 0.7);
    --glass-border: rgba(255, 255, 255, 0.1);
    --accent: #38bdf8;
    --accent-hover: #7dd3fc;
    --success: #10b981;
}

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

body {
    font-family: 'Inter', sans-serif;
    background: linear-gradient(135deg, var(--bg-darker), var(--bg-dark));
    color: var(--text-primary);
    min-height: 100vh;
    overflow-x: hidden;
}

.hidden {
    display: none !important;
}

.glass-panel {
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.3);
}

.app-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 2rem;
}

header {
    padding: 2rem;
    margin-bottom: 2rem;
    position: sticky;
    top: 1rem;
    z-index: 100;
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: white;
    background: linear-gradient(135deg, #fff, #a0a4ab);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.5rem;
    text-align: center;
}

header > p {
    color: var(--text-secondary);
    font-size: 1.1rem;
    margin-bottom: 2rem;
    text-align: center;
}

.dashboard {
    display: flex;
    gap: 2rem;
    background: rgba(0, 0, 0, 0.2);
    padding: 1.5rem;
    border-radius: 12px;
    border: 1px solid var(--glass-border);
    flex-wrap: wrap;
    align-items: stretch;
}

.info-panel {
    flex: 1;
    min-width: 270px;
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
    background: rgba(255, 255, 255, 0.03);
    padding: 1rem;
    border-radius: 8px;
    border: 1px solid var(--glass-border);
}

.info-panel.highlight {
    border-color: rgba(56, 189, 248, 0.3);
}

.info-panel h3 {
    color: var(--text-secondary);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.panel-content {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex: 1;
}

.panel-content.empty {
    justify-content: center;
    color: var(--text-secondary);
    font-style: italic;
    border: 1px dashed rgba(255,255,255,0.2);
    border-radius: 8px;
    padding: 1rem;
}

.reference-content {
    display: flex;
    align-items: center;
    gap: 1rem;
    width: 100%;
}

.swatch-preview {
    width: 60px;
    height: 60px;
    border-radius: 8px;
    border: 2px solid var(--glass-border);
    box-shadow: 0 4px 10px rgba(0,0,0,0.3);
}
.empty-swatch {
    background: repeating-linear-gradient(45deg, rgba(255,255,255,0.05), rgba(255,255,255,0.05) 10px, transparent 10px, transparent 20px);
}

.details {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 0.3rem;
}

.detail-name {
    font-size: 1rem;
    font-weight: 700;
    white-space: nowrap;
}

.detail-code {
    color: var(--text-secondary);
    font-size: 0.85rem;
}

.detail-lrv {
    color: var(--text-primary);
    font-weight: 500;
    font-size: 0.9rem;
}

.detail-contrast {
    color: var(--success);
    font-weight: 700;
    font-size: 0.9rem;
}

.controls-panel {
    flex: 1.5;
    min-width: 300px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 1.5rem;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.accent-text {
    color: var(--accent);
    font-weight: 700;
}

input[type="range"] {
    -webkit-appearance: none;
    width: 100%;
    height: 6px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 4px;
    outline: none;
}
input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--accent);
    cursor: pointer;
    transition: transform 0.2s;
}
input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

.custom-slider-thumb {
    position: absolute;
    width: 20px;
    height: 20px;
    background: var(--accent);
    border-radius: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    cursor: grab;
    z-index: 10;
    transition: transform 0.1s, box-shadow 0.1s;
    box-shadow: 0 2px 5px rgba(0,0,0,0.5);
}
.custom-slider-thumb:hover {
    transform: translate(-50%, -50%) scale(1.2);
}
.custom-slider-thumb:active {
    cursor: grabbing;
}

.slider-marks {
    display: flex;
    justify-content: space-between;
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.search-input {
    padding: 0.8rem 1rem;
    border-radius: 8px;
    border: 1px solid var(--glass-border);
    background: rgba(0, 0, 0, 0.3);
    color: white;
    font-size: 0.9rem;
    width: 100%;
}
.search-input:focus {
    outline: none;
    border-color: var(--accent);
}

.btn {
    padding: 0.5rem;
    background: rgba(255, 255, 255, 0.05);
    color: white;
    border: 1px solid var(--glass-border);
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.85rem;
    margin-top: 0.5rem;
}
.btn:hover {
    background: rgba(255, 255, 255, 0.1);
}

/* Groups and Tiles */
.groups-wrapper {
    display: flex;
    flex-wrap: wrap;
    gap: 3rem;
    justify-content: center;
}

.group-container {
    background: rgba(255,255,255,0.02);
    border: 1px solid var(--glass-border);
    border-radius: 12px;
    overflow: hidden;
    width: fit-content;
}

.group-header {
    padding: 1rem;
    background: rgba(255,255,255,0.05);
    border-bottom: 1px solid var(--glass-border);
}

.group-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    background: #091330;
    width: fit-content;
    padding-left: 10px;
    padding-right: 10px;
    padding-top: 5px;
    padding-bottom: 5px;
    border-radius: 5px;
}

.color-grid-9 {
    display: grid;
    grid-template-rows: repeat(8, 45px);
    grid-template-columns: repeat(9, 60px);
    grid-auto-columns: 60px;
    grid-auto-flow: column;
    gap: 8px;
    padding: 1.5rem;
}

.color-tile {
    width: 100%;
    height: 100%;
    border-radius: 4px;
    border: 1px solid rgba(255,255,255,0.1);
    cursor: pointer;
    transition: transform 0.1s, box-shadow 0.1s;
    position: relative;
}

.color-tile:hover {
    transform: scale(1.3);
    box-shadow: 0 4px 12px rgba(0,0,0,0.4);
    z-index: 10;
    border-color: rgba(255,255,255,0.5);
}

/* Down-scale layout for smaller screens / lower resolutions */
@media (max-width: 1300px), (max-height: 800px) {
    .app-container {
        padding: 1rem;
    }
    header {
        padding: 1rem;
        margin-bottom: 1rem;
    }
    h1 {
        font-size: 2rem;
    }
    header > p {
        margin-bottom: 1rem;
        font-size: 1rem;
    }
    .dashboard {
        padding: 1rem;
        gap: 1rem;
    }
    .info-panel {
        padding: 0.75rem;
        min-width: 220px;
    }
    .controls-panel {
        min-width: 240px;
        gap: 1rem;
    }
    .swatch-preview {
        width: 45px;
        height: 45px;
    }
    .color-grid-9 {
        grid-template-rows: repeat(8, 40px);
        grid-template-columns: repeat(9, 50px);
        grid-auto-columns: 50px;
        padding: 1rem;
    }
    .groups-wrapper {
        gap: 2rem;
    }
}

@media (max-width: 1100px), (max-height: 700px) {
    .app-container {
        padding: 0.5rem;
    }
    header {
        padding: 0.75rem;
        margin-bottom: 0.75rem;
        position: static; /* Let header scroll to save vertical space */
    }
    h1 {
        font-size: 1.5rem;
    }
    header > p {
        margin-bottom: 0.5rem;
        font-size: 0.9rem;
    }
    .dashboard {
        padding: 0.75rem;
        gap: 0.75rem;
    }
    .info-panel {
        padding: 0.5rem;
        min-width: 180px;
    }
    .controls-panel {
        min-width: 200px;
        gap: 0.75rem;
    }
    .swatch-preview {
        width: 35px;
        height: 35px;
    }
    .detail-name {
        font-size: 0.9rem;
    }
    .detail-code, .detail-lrv, .detail-contrast {
        font-size: 0.8rem;
    }
    .color-grid-9 {
        grid-template-rows: repeat(8, 35px);
        grid-template-columns: repeat(9, 45px);
        grid-auto-columns: 45px;
        padding: 0.75rem;
        gap: 5px;
    }
    .groups-wrapper {
        gap: 1rem;
    }
    .group-title {
        font-size: 1rem;
    }
}