:root {
    --bg-color: #0f172a;
    --text-color: #f8fafc;
    --panel-bg: rgba(30, 41, 59, 0.7);
    --panel-border: rgba(148, 163, 184, 0.1);

    --color-a: #f43f5e;
    /* Rose */
    --color-b: #3b82f6;
    /* Blue */
    --color-c: #10b981;
    /* Emerald */
    --color-highlight: #fbbf24;
    /* Amber */
    --color-root: #22d3ee;
    /* Cyan for visibility in dark mode */

    --font-main: 'Outfit', sans-serif;
    --font-code: 'Source Code Pro', monospace;
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: var(--font-main);
    line-height: 1.6;
    overflow-x: hidden;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    position: relative;
    z-index: 1;
}

.background-curves {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    pointer-events: none;
    overflow: hidden;
    display: flex;
    align-items: flex-end;
}

.background-curves svg {
    width: 100%;
    min-width: 1200px;
    height: auto;
    display: block;

    .app-container {
        max-width: 1200px;
        margin: 0 auto;
        padding: 1rem;
        width: 100%;
        flex: 1;
        display: flex;
        flex-direction: column;
    }

    text-align: left;
    margin-bottom: 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.logo-container {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.app-logo {
    width: 60px;
    height: 60px;
    filter: drop-shadow(0 0 10px rgba(59, 130, 246, 0.5));
}

.top-nav {
    display: flex;
    gap: 1rem;
}

.nav-link {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 600;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--panel-border);
    transition: all 0.2s ease;
}

.nav-link:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.2);
    transform: translateY(-1px);
}

h1 {
    font-weight: 700;
    font-size: 2rem;
    letter-spacing: -0.02em;
    background: linear-gradient(to right, #e2e8f0, #94a3b8);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin: 0;
    line-height: 1.2;
}

.subtitle {
    color: #94a3b8;
    font-size: 1rem;
    margin: 0;
    font-family: var(--font-code);
}

.instructions {
    margin-bottom: 1.5rem;
    cursor: pointer;
}

.instructions summary {
    font-weight: 600;
    color: #cbd5e1;
    cursor: pointer;
    list-style: none;
    /* Hide default triangle in some browsers */
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.instructions summary::-webkit-details-marker {
    display: none;
}

.instructions summary::after {
    content: '+';
    font-size: 1.2rem;
    font-weight: 300;
    margin-left: auto;
}

details[open] summary::after {
    content: '-';
}

.instructions-content {
    margin-top: 1rem;
    font-size: 0.95rem;
    color: #94a3b8;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-5px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.instructions-content ul {
    list-style: none;
    padding-left: 0;
    margin: 0.5rem 0;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 0.5rem;
}

.instructions-content li {
    background: rgba(0, 0, 0, 0.2);
    padding: 0.5rem;
    border-radius: 0.25rem;
}

.instructions-content strong {
    color: #e2e8f0;
}

main {
    display: grid;
    grid-template-columns: 1fr 350px;
    grid-template-rows: auto 1fr;
    gap: 1.5rem;
    flex: 1;
    min-height: 0;
    /* Important for grid within flex */
}

/* Graph Section */
.graph-section {
    grid-column: 1;
    grid-row: 1 / 3;
    background: #020617;
    border-radius: 1rem;
    border: 1px solid var(--panel-border);
    position: relative;
    overflow: hidden;
    display: flex;
    flex-direction: column;
}

canvas {
    width: 100%;
    height: 100%;
    display: block;
}

.graph-legends {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: rgba(0, 0, 0, 0.6);
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    display: flex;
    gap: 1rem;
    font-size: 0.9rem;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    display: inline-block;
}

.root-dot {
    background-color: var(--color-root);
    border: 2px solid var(--color-root);
    box-shadow: 0 0 8px var(--color-root);
}

/* Will be updated by JS actually, but default here */
.vertex-dot {
    background-color: var(--color-highlight);
}

.y-intercept-dot {
    background-color: var(--color-c);
}

/* Glass Panel Utilities */
.glass-panel {
    background: var(--panel-bg);
    backdrop-filter: blur(12px);
    border: 1px solid var(--panel-border);
    border-radius: 1rem;
    padding: 1.5rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

/* Controls Section */
.controls-section {
    grid-column: 2;
    grid-row: 1;
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

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

.control-group label {
    display: flex;
    justify-content: space-between;
    font-weight: 600;
    font-family: var(--font-code);
}

.a-group label {
    color: var(--color-a);
}

.b-group label {
    color: var(--color-b);
}

.c-group label {
    color: var(--color-c);
}

input[type=range] {
    -webkit-appearance: none;
    width: 100%;
    background: transparent;
}

input[type=range]::-webkit-slider-thumb {
    -webkit-appearance: none;
    height: 18px;
    width: 18px;
    border-radius: 50%;
    background: #fff;
    cursor: pointer;
    margin-top: -7px;
    box-shadow: 0 0 10px rgba(255, 255, 255, 0.3);
}

input[type=range]::-webkit-slider-runnable-track {
    width: 100%;
    height: 4px;
    cursor: pointer;
    background: #334155;
    border-radius: 2px;
}

.a-group input[type=range]::-webkit-slider-thumb {
    background: var(--color-a);
    box-shadow: 0 0 10px var(--color-a);
}

.b-group input[type=range]::-webkit-slider-thumb {
    background: var(--color-b);
    box-shadow: 0 0 10px var(--color-b);
}

.c-group input[type=range]::-webkit-slider-thumb {
    background: var(--color-c);
    box-shadow: 0 0 10px var(--color-c);
}

/* Formula Section */
.formula-section {
    grid-column: 2;
    grid-row: 2;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    overflow-y: auto;
}

.formula-section h2 {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
    color: #cbd5e1;
}

.formula-display {
    font-family: 'Times New Roman', serif;
    font-style: italic;
    font-size: 1.5rem;
    display: flex;
    justify-content: center;
    margin-bottom: 1rem;
}

.fraction {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    vertical-align: middle;
    margin: 0 0.2rem;
}

.numerator {
    border-bottom: 2px solid var(--text-color);
    padding: 0 0.5rem 0.2rem;
    text-align: center;
}

.radical {
    border-top: 2px solid var(--text-color);
    padding-top: 1px;
}

.denominator {
    padding-top: 0.2rem;
    text-align: center;
}

.var-a {
    color: var(--color-a);
    font-weight: bold;
}

.var-b {
    color: var(--color-b);
    font-weight: bold;
}

.var-c {
    color: var(--color-c);
    font-weight: bold;
}

.calculation-steps {
    font-size: 0.95rem;
    color: #94a3b8;
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
}

.step-row {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.discriminant-val {
    color: var(--color-highlight);
    font-weight: bold;
}

.result-display {
    margin-top: auto;
    padding-top: 1rem;
    font-size: 1.1rem;
    font-weight: 600;
    text-align: center;
}

/* Responsive */
@media (max-width: 900px) {
    main {
        grid-template-columns: 1fr;
        grid-template-rows: 400px auto auto;
    }

    .graph-section {
        grid-column: 1;
        grid-row: 1;
    }

    .controls-section {
        grid-column: 1;
        grid-row: 2;
    }

    .formula-section {
        grid-column: 1;
        grid-row: 3;
    }
}