:root {
    --bg-primary: #0f172a;
    --bg-card: #1e293b;
    --bg-input: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --accent: #38bdf8;
    --accent-hover: #0ea5e9;
    --border: #475569;
    --success: #22c55e;
}

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

body {
    font-family: 'Noto Sans SC', sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    padding: 24px 16px;
    background-image:
        radial-gradient(ellipse at top, #1e293b 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(56, 189, 248, 0.05) 0%, transparent 40%);
}

.container {
    max-width: 900px;
    margin: 0 auto;
}

header {
    text-align: center;
    margin-bottom: 32px;
}

h1 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 8px;
    background: linear-gradient(135deg, var(--accent), #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.main-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}

@media (max-width: 768px) {
    .main-grid {
        grid-template-columns: 1fr;
    }
}

.card {
    background: var(--bg-card);
    border-radius: 12px;
    padding: 24px;
    border: 1px solid var(--border);
}

.card-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.card-title::before {
    content: '';
    width: 4px;
    height: 20px;
    background: var(--accent);
    border-radius: 2px;
}

/* Color Picker Section */
.picker-container {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.color-input-wrapper {
    display: flex;
    align-items: center;
    gap: 16px;
}

.color-preview-large {
    width: 100px;
    height: 100px;
    border-radius: 12px;
    border: 3px solid var(--border);
    cursor: pointer;
    position: relative;
    overflow: hidden;
    transition: transform 0.2s, border-color 0.2s;
}

.color-preview-large:hover {
    transform: scale(1.05);
    border-color: var(--accent);
}

.color-preview-large input[type="color"] {
    position: absolute;
    width: 150%;
    height: 150%;
    top: -25%;
    left: -25%;
    cursor: pointer;
    border: none;
}

.hex-input-group {
    flex: 1;
}

.hex-input-group label {
    display: block;
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.hex-input-group input {
    width: 100%;
    padding: 12px 16px;
    background: var(--bg-input);
    border: 2px solid var(--border);
    border-radius: 8px;
    color: var(--text-primary);
    font-family: 'JetBrains Mono', monospace;
    font-size: 1.1rem;
    transition: border-color 0.2s;
}

.hex-input-group input:focus {
    outline: none;
    border-color: var(--accent);
}

/* RGB Sliders */
.rgb-sliders {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.slider-group {
    display: flex;
    align-items: center;
    gap: 12px;
}

.slider-label {
    width: 24px;
    height: 24px;
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 0.85rem;
}

.slider-label.red { background: #ef4444; }
.slider-label.green { background: #22c55e; }
.slider-label.blue { background: #3b82f6; }

.slider-wrapper {
    flex: 1;
    position: relative;
}

.slider-wrapper input[type="range"] {
    width: 100%;
    height: 8px;
    -webkit-appearance: none;
    appearance: none;
    background: var(--bg-input);
    border-radius: 4px;
    outline: none;
}

.slider-wrapper input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--accent);
    cursor: pointer;
    border: 3px solid var(--bg-card);
    box-shadow: 0 2px 8px rgba(0,0,0,0.3);
    transition: transform 0.15s;
}

.slider-wrapper input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.15);
}

.slider-wrapper input[type="range"].red::-webkit-slider-thumb { background: #ef4444; }
.slider-wrapper input[type="range"].green::-webkit-slider-thumb { background: #22c55e; }
.slider-wrapper input[type="range"].blue::-webkit-slider-thumb { background: #3b82f6; }

.slider-value {
    width: 60px;
    padding: 8px;
    background: var(--bg-input);
    border: 2px solid var(--border);
    border-radius: 6px;
    color: var(--text-primary);
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.9rem;
    text-align: center;
}

.slider-value:focus {
    outline: none;
    border-color: var(--accent);
}

/* Preview Section */
.preview-section {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.preview-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
}

.preview-box {
    padding: 16px;
    border-radius: 8px;
    text-align: center;
    border: 2px solid var(--border);
}

.preview-box .label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.preview-color {
    height: 60px;
    border-radius: 6px;
    margin-bottom: 8px;
    border: 1px solid rgba(255,255,255,0.1);
}

.preview-box .value {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.color-diff {
    text-align: center;
    padding: 12px;
    background: rgba(56, 189, 248, 0.1);
    border-radius: 8px;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.color-diff strong {
    color: var(--accent);
}

/* Output Section */
.output-section {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.output-grid {
    display: grid;
    gap: 12px;
}

.output-item {
    display: flex;
    align-items: center;
    gap: 12px;
}

.output-label {
    width: 80px;
    font-size: 0.85rem;
    color: var(--text-secondary);
    flex-shrink: 0;
}

.output-value-wrapper {
    flex: 1;
    display: flex;
    gap: 8px;
}

.output-value {
    flex: 1;
    padding: 10px 14px;
    background: var(--bg-input);
    border: 2px solid var(--border);
    border-radius: 6px;
    color: var(--text-primary);
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.95rem;
}

.copy-btn {
    padding: 10px 14px;
    background: var(--accent);
    border: none;
    border-radius: 6px;
    color: #000;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s, transform 0.15s;
    font-size: 0.85rem;
    white-space: nowrap;
}

.copy-btn:hover {
    background: var(--accent-hover);
    transform: translateY(-1px);
}

.copy-btn:active {
    transform: translateY(0);
}

.copy-btn.copied {
    background: var(--success);
}

/* Binary Display */
.binary-display {
    background: var(--bg-input);
    border-radius: 8px;
    padding: 16px;
    margin-top: 8px;
}

.binary-bits {
    display: flex;
    justify-content: center;
    gap: 4px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.8rem;
    margin-bottom: 12px;
}

.binary-group {
    display: flex;
    gap: 2px;
}

.binary-group.red { color: #ef4444; }
.binary-group.green { color: #22c55e; }
.binary-group.blue { color: #3b82f6; }

.binary-bit {
    padding: 2px 1px;
    background: rgba(255,255,255,0.05);
    border-radius: 2px;
}

.binary-labels {
    display: flex;
    justify-content: center;
    gap: 24px;
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.binary-labels span {
    width: 50px;
    text-align: center;
}

/* C Code Section */
.code-section {
    background: var(--bg-input);
    border-radius: 8px;
    padding: 16px;
    margin-top: 8px;
}

.code-section .label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 12px;
}

.code-block {
    background: #0f172a;
    border-radius: 6px;
    padding: 14px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.9rem;
    color: #a5b4fc;
    overflow-x: auto;
    white-space: pre-wrap;
    word-break: break-all;
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--success);
    color: #000;
    padding: 12px 24px;
    border-radius: 8px;
    font-weight: 600;
    opacity: 0;
    transition: transform 0.3s, opacity 0.3s;
    z-index: 1000;
}

.toast.show {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
}

footer {
    text-align: center;
    margin-top: 32px;
    color: var(--text-secondary);
    font-size: 0.85rem;
}

/* Color Palette */
.palette-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 4px;
    padding: 8px;
    width: 100%;
}

.palette-swatch {
    width: 24px;
    height: 24px;
    border-radius: 3px;
    cursor: pointer;
    transition: transform 0.15s, box-shadow 0.15s;
    border: 1px solid transparent;
    flex-shrink: 0;
}

.palette-swatch:hover {
    transform: scale(1.3);
    box-shadow: 0 4px 12px rgba(0,0,0,0.5);
    border-color: var(--accent);
    z-index: 10;
}

.palette-swatch .swatch-hex,
.palette-swatch .swatch-name {
    display: none;
}

.palette-section {
    margin-bottom: 20px;
    width: 100%;
}

.palette-section-title {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-bottom: 12px;
    font-weight: 500;
}

.palette-row {
    display: flex;
    flex-wrap: wrap;
    gap: 4px;
    margin-bottom: 16px;
}