:root {
    /* Colors - Modern gradient palette */
    --primary-color: #4C061D;
    --primary-hover: #D17A22;
    --primary-gradient: linear-gradient(135deg, #4C061D 0%, #D17A22 50%, #B4C292 100%);
    --danger-color: #736F4E;
    --danger-hover: #B4C292;
    --danger-gradient: linear-gradient(135deg, #736F4E 0%, #B4C292 100%);
    --text-primary: #1a202c;
    --text-secondary: #4a5568;
    --text-muted: #718096;
    --bg-primary: #ffffff;
    --bg-secondary: #F5F3EB;
    --bg-tertiary: #B4C292;
    --border-color: #736F4E;
    --border-light: #736F4E;
    --focus-color: #D17A22;
    --focus-outline: 0 0 0 3px rgba(209, 122, 34, 0.15);

    /* Spacing - More compact */
    --spacing-xs: 2px;
    --spacing-sm: 4px;
    --spacing-md: 8px;
    --spacing-lg: 12px;
    --spacing-xl: 16px;

    /* Border radius */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 12px;

    /* Shadows - Enhanced */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08), 0 1px 2px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07), 0 2px 4px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1), 0 4px 6px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.1), 0 10px 10px rgba(0, 0, 0, 0.04);

    /* Transitions - Enhanced */
    --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Inter', sans-serif;
    min-height: 75vh;
    color: var(--text-primary);
    background: linear-gradient(135deg, #F5F3EB 0%, #D4C9B5 100%);
    margin: 20px auto;
    max-width: 1200px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
}

.container {
    display: grid;
    grid-template-columns: 65% 35%;
    min-height: 75vh;
    background: var(--bg-primary);
    border-radius: var(--radius-lg);
}

.plot-section {
    padding: var(--spacing-lg);
    border-right: 1px solid var(--border-color);
    background: var(--bg-secondary);
    position: relative;
}

#plot {
    width: 100%;
    height: 100%;
    border-radius: var(--radius-md);
    background: var(--bg-primary);
    box-shadow: var(--shadow-md);
    transition: transform var(--transition-normal);
}

#plot:hover {
    transform: scale(1.01);
}

.controls-section {
    padding: var(--spacing-lg);
    overflow-y: auto;
    background: linear-gradient(180deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
    scrollbar-width: thin;
    scrollbar-color: var(--border-color) transparent;
}

.controls-section::-webkit-scrollbar {
    width: 6px;
}

.controls-section::-webkit-scrollbar-track {
    background: transparent;
}

.controls-section::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 3px;
}

.controls-section::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

.polynomial-manager h2, .range-controls h3 {
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
    font-weight: 600;
    font-size: 14px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

#add-polynomial {
    background: var(--primary-gradient);
    color: var(--bg-primary);
    border: none;
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-md);
    cursor: pointer;
    margin-bottom: var(--spacing-lg);
    transition: all var(--transition-normal);
    font-weight: 600;
    font-size: 13px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    box-shadow: var(--shadow-md);
    position: relative;
    overflow: hidden;
}

#add-polynomial::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left var(--transition-slow);
}

#add-polynomial:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

#add-polynomial:hover::before {
    left: 100%;
}

#add-polynomial:active {
    transform: translateY(0);
    box-shadow: var(--shadow-sm);
}

#add-polynomial:focus {
    outline: none;
    box-shadow: var(--focus-outline), var(--shadow-md);
}

.range-inputs {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-md);
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.range-inputs label {
    display: block;
    margin-bottom: var(--spacing-xs);
    color: var(--text-secondary);
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.3px;
}

.range-inputs input {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 2px solid var(--border-light);
    border-radius: var(--radius-sm);
    transition: all var(--transition-normal);
    font-size: 13px;
    background: var(--bg-primary);
}

.range-inputs input:focus {
    outline: none;
    border-color: var(--focus-color);
    box-shadow: var(--focus-outline);
    transform: translateY(-1px);
}

.range-inputs input:hover {
    border-color: var(--text-muted);
}

.polynomial-card {
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-md);
    background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-sm);
    position: relative;
    overflow: hidden;
}

.polynomial-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--primary-gradient);
    opacity: 0;
    transition: opacity var(--transition-normal);
}

.polynomial-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.polynomial-card:hover::before {
    opacity: 1;
}

.polynomial-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-sm);
}

.equation {
    font-family: 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', monospace;
    font-size: 12px;
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-primary);
    border-radius: var(--radius-sm);
    border-left: 3px solid currentColor;
    color: var(--text-primary);
    box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.05);
}

.remove-polynomial {
    background: var(--danger-gradient);
    color: var(--bg-primary);
    border: none;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 10px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.3px;
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-sm);
}

.remove-polynomial:hover,
.remove-polynomial:focus {
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.remove-polynomial:active {
    transform: translateY(0);
    box-shadow: var(--shadow-sm);
}

.remove-polynomial:focus {
    outline: none;
    box-shadow: var(--focus-outline), var(--shadow-sm);
}

.coefficient-slider {
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-sm);
    background: var(--bg-primary);
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-light);
}

.coefficient-slider label {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-sm);
    font-size: 11px;
    color: var(--text-secondary);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.3px;
}

.coefficient-slider input[type="range"] {
    width: 100%;
    margin-bottom: var(--spacing-xs);
    cursor: pointer;
    height: 6px;
    border-radius: 3px;
    background: var(--border-light);
    outline: none;
    -webkit-appearance: none;
    appearance: none;
}

.coefficient-slider input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--primary-gradient);
    cursor: pointer;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
}

.coefficient-slider input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
    box-shadow: var(--shadow-md);
}

.coefficient-slider input[type="range"]::-moz-range-thumb {
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--primary-gradient);
    cursor: pointer;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
    border: none;
}

.coefficient-slider input[type="range"]::-moz-range-thumb:hover {
    transform: scale(1.2);
    box-shadow: var(--shadow-md);
}

.coefficient-slider input[type="range"]:focus {
    outline: none;
}

.coefficient-slider input[type="range"]:focus::-webkit-slider-thumb {
    box-shadow: var(--focus-outline), var(--shadow-md);
}

.coefficient-slider input[type="range"]:focus::-moz-range-thumb {
    box-shadow: var(--focus-outline), var(--shadow-md);
}

.coefficient-value {
    font-family: 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', monospace;
    font-weight: 700;
    min-width: 35px;
    text-align: right;
    color: var(--text-primary);
    font-size: 12px;
    background: var(--bg-tertiary);
    padding: 2px 4px;
    border-radius: var(--radius-sm);
}

@media (max-width: 768px) {
    body {
        margin: 10px;
    }

    .container {
        grid-template-columns: 1fr;
        grid-template-rows: auto auto;
    }

    .plot-section {
        border-right: none;
        border-bottom: 1px solid var(--border-color);
        padding: var(--spacing-md);
    }

    .controls-section {
        padding: var(--spacing-md);
    }

    .range-inputs {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
    }
}

/* Reduced motion support */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --border-color: #000000;
        --text-secondary: var(--text-primary);
        --bg-secondary: var(--bg-primary);
    }

    .polynomial-card,
    .equation {
        border: 2px solid var(--text-primary);
    }
}