:root {
    /* Unified color scheme - optimized for dark mode */
    --color-primary: hsl(217, 91%, 70%);
    --color-primary-dark: hsl(217, 91%, 60%);
    --color-primary-light: hsl(217, 91%, 80%);
    --color-secondary: hsl(342, 89%, 58%);
    --color-accent: hsl(51, 100%, 60%);

    /* Vector-specific colors */
    --vector-a-color: hsl(233, 88%, 50%);
    --vector-b-color: hsl(323, 88%, 50%);
    --vector-brot-color: hsl(323, 88%, 60%);
    --vector-c-color: hsl(143, 88%, 50%);
    --prod-a-b-c-color: hsl(53, 88%, 50%);
    --prod-c-a-b-color: hsl(26, 88%, 50%);

    --wedge-a-b-color: hsl(293, 40%, 50%);
    --dot-a-b-color: hsl(113, 40%, 50%);

    /* Dark theme neutral colors (default) */
    --color-text: hsl(210, 20%, 98%);
    --color-text-muted: hsl(210, 10%, 75%);
    --color-text-light: hsl(210, 10%, 65%);
    --color-background: hsl(210, 20%, 4%);
    --color-surface: hsl(210, 15%, 8%);
    --color-border: hsl(210, 15%, 25%);
    --color-border-light: hsl(210, 15%, 20%);

    /* HSL values for use with alpha */
    --color-background-hsl: 210, 20%, 4%;

    /* Shadows - Dark theme */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.6), 0 10px 10px -5px rgba(0, 0, 0, 0.4);

    /* Typography */
    --font-family-base: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-family-mono: 'Fira Code', Consolas, Monaco, 'Andale Mono', 'Ubuntu Mono', monospace;

    /* Fluid typography scales */
    --font-size-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
    --font-size-sm: clamp(0.875rem, 0.8rem + 0.375vw, 1rem);
    --font-size-base: clamp(1rem, 0.9rem + 0.5vw, 1.125rem);
    --font-size-lg: clamp(1.125rem, 1rem + 0.625vw, 1.25rem);
    --font-size-xl: clamp(1.25rem, 1.1rem + 0.75vw, 1.5rem);
    --font-size-2xl: clamp(1.5rem, 1.3rem + 1vw, 2rem);
    --font-size-3xl: clamp(1.875rem, 1.6rem + 1.375vw, 2.5rem);
    --font-size-4xl: clamp(2.25rem, 1.9rem + 1.75vw, 3.5rem);

    /* Line heights */
    --line-height-tight: 1.25;
    --line-height-snug: 1.375;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.625;
    --line-height-loose: 2;

    /* Spacing scale */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;
    --space-4xl: 6rem;
    --space-5xl: 8rem;

    /* Breakpoints (for container queries) */
    --breakpoint-sm: 640px;
    --breakpoint-md: 768px;
    --breakpoint-lg: 1024px;
    --breakpoint-xl: 1280px;
    --breakpoint-2xl: 1536px;

    /* Animation */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);

    /* Border radius */
    --radius-sm: 0.125rem;
    --radius-md: 0.375rem;
    --radius-lg: 0.5rem;
    --radius-xl: 0.75rem;
    --radius-2xl: 1rem;
    --radius-full: 9999px;

    /* Z-index scale */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal-backdrop: 1040;
    --z-modal: 1050;
    --z-popover: 1060;
    --z-tooltip: 1070;
}

/* ===========================
   Reset & Base Styles
   =========================== */
*,
*::before,
*::after {
    box-sizing: border-box;
}

* {
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: 5rem;
}

@media (prefers-reduced-motion: reduce) {

    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

body {
    font-family: var(--font-family-base);
    font-size: var(--font-size-base);
    line-height: var(--line-height-normal);
    color: var(--color-text);
    background-color: var(--color-background);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
    overflow-x: hidden;
}

/* ===========================
   Typography
   =========================== */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-weight: 700;
    line-height: var(--line-height-tight);
    letter-spacing: -0.025em;
}

h1 {
    font-size: var(--font-size-4xl);
}

h2 {
    font-size: var(--font-size-3xl);
}

h3 {
    font-size: var(--font-size-2xl);
}

h4 {
    font-size: var(--font-size-xl);
}

h5 {
    font-size: var(--font-size-lg);
}

h6 {
    font-size: var(--font-size-base);
}

p {
    margin-bottom: var(--space-md);
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover,
a:focus {
    color: var(--color-primary-dark);
}

a:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

.container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.header {
    padding: var(--space-xl);
    text-align: center;
    background: hsla(var(--color-background-hsl), 0.8);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border-light);
}

.title {
    font-size: 2.5rem;
    font-weight: 600;
    background: linear-gradient(135deg,
            var(--color-primary) 0%,
            var(--color-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--space-sm);
}

.subtitle {
    font-size: 1.1rem;
    color: var(--color-text-muted);
    font-weight: 300;
}

.main-content {
    flex: 1;
    display: grid;
    grid-template-columns: 1fr 320px;
    gap: var(--space-xl);
    padding: var(--space-xl);
    min-height: 0;
}

.canvas-container {
    position: relative;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

#threejs-canvas {
    width: 100%;
    height: 100%;
    display: block;
    cursor: grab;
}

#threejs-canvas:active {
    cursor: grabbing;
}

.canvas-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    pointer-events: none;
}

.controls {
    position: absolute;
    top: var(--space-md);
    right: var(--space-md);
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
    pointer-events: auto;
}

/* Buttons */
.btn {
    padding: var(--space-sm) var(--space-md);
    border: none;
    border-radius: var(--radius-lg);
    font-family: var(--font-family-base);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: 0.875rem;
}

.btn-secondary {
    background: hsla(var(--color-background-hsl), 0.2);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

.btn-secondary:hover {
    background: var(--color-surface);
    transform: translateY(-1px);
}

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

.btn-normalize {
    background: hsla(var(--color-background-hsl), 0.2);
    color: var(--color-text-muted);
    border: 1px solid var(--color-border);
    padding: var(--space-xs) var(--space-sm);
    font-size: 0.75rem;
    border-radius: var(--radius-md);
    min-width: auto;
    flex-shrink: 0;
}

.btn-normalize:hover {
    background: var(--color-surface);
    color: var(--color-text);
    border-color: var(--color-border-light);
}

.btn-normalize:active {
    transform: scale(0.95);
}

.btn-toggle-norm {
    background: hsla(var(--color-background-hsl), 0.2);
    color: var(--color-text-muted);
    border: 1px solid var(--color-border);
    padding: var(--space-xs);
    font-size: 0.75rem;
    border-radius: var(--radius-md);
    min-width: auto;
    flex-shrink: 0;
    transition: transform var(--transition-fast);
}

.btn-toggle-norm:hover {
    background: var(--color-surface);
    color: var(--color-text);
    border-color: var(--color-border-light);
}

.btn-toggle-norm:active {
    transform: scale(0.95);
}

.btn-toggle-norm.collapsed {
    transform: rotate(180deg);
}

.example-btn {
    background: hsla(var(--color-background-hsl), 0.2);
    color: var(--color-text-muted);
    border: 1px solid var(--color-border);
    padding: var(--space-sm) var(--space-md);
    font-size: 0.875rem;
    border-radius: var(--radius-md);
    margin: var(--space-sm) auto;
    display: block;
    width: 100%;
    max-width: none;
    gap: var(--space-xs);
    text-align: center;
}

.example-btn:hover {
    background: var(--color-surface);
    color: var(--color-text);
    border-color: var(--color-border-light);
    transform: translateY(-1px);
}

.example-btn:active {
    transform: scale(0.95);
}

.return-button {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 3.5rem;
    height: 3.5rem;
    background: hsla(var(--color-background-hsl), 0.2);
    color: var(--color-text-muted);
    border: 1px solid var(--color-border);
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    transition: all var(--transition-normal);
    z-index: 1000;
    opacity: 0.95;
}

.return-button:hover {
    background: var(--color-surface);
    color: var(--color-text);
    border-color: var(--color-border-light);
    opacity: 1;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.return-button:active {
    transform: scale(0.95);
}

.return-button.hidden {
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
}

.norm-display {
    transition: all var(--transition-normal);
    overflow: hidden;
}

.norm-display.collapsed {
    max-height: 0;
    opacity: 0;
    margin: 0;
    padding: 0;
}

/* Sidebar */
.sidebar {
    display: flex;
    flex-direction: column;
    gap: var(--space-xl);
}

.info-panel {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    box-shadow: var(--shadow-lg);
}

.info-panel h2 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--space-lg);
    color: var(--color-text);
}

.vector-info {
    margin-bottom: var(--space-lg);
    padding-bottom: var(--space-lg);
    border-bottom: 1px solid var(--color-border);
}

.vector-info:last-child {
    margin-bottom: 0;
    padding-bottom: 0;
    border-bottom: none;
}

.vector-info h3 {
    font-size: 1rem;
    font-weight: 500;
    margin-bottom: var(--space-sm);
    color: var(--color-text);
}

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

.vector-info-group {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    flex-grow: 1;
}

.vector-color {
    width: 16px;
    height: 16px;
    border-radius: 50%;
    border: 2px solid rgba(255, 255, 255, 0.2);
    cursor: pointer;
    transition: var(--transition-fast);
    position: relative;
}

.vector-color:hover {
    transform: scale(1.1);
    border-color: rgba(255, 255, 255, 0.4);
}

.vector-color.hidden {
    opacity: 0.3;
    filter: grayscale(100%);
}

.vector-color.hidden::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 2px;
    height: 120%;
    background-color: var(--color-text);
    transform: translate(-50%, -50%) rotate(45deg);
    border-radius: 1px;
}

.vector-color-spacer {
    width: 16px;
    height: 16px;
    /* Invisible spacer to maintain alignment */
}

.vector-a {
    background-color: var(--vector-a-color);
}

.vector-b {
    background-color: var(--vector-b-color);
}

.vector-brot {
    background-color: var(--vector-brot-color);
}

.vector-c {
    background-color: var(--vector-c-color);
}

.wedge-a-b {
    background-color: var(--wedge-a-b-color);
}

.dot-a-b {
    background-color: var(--dot-a-b-color);
}

.prod-a-b-c {
    background-color: var(--prod-a-b-c-color);
}

.prod-c-a-b {
    background-color: var(--prod-c-a-b-color);
}

.vector-coords {
    display: flex;
    flex-direction: column;
    gap: var(--space-xs);
    font-family: var(--font-family-mono);
    font-size: 0.875rem;
}

.vector-coords span {
    color: var(--color-text-muted);
}

.vector-fallback {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    font-family: var(--font-family-mono);
    font-size: 0.875rem;
}

.vector-fallback>span {
    font-size: 1.5rem;
    color: var(--color-text);
    font-weight: 300;
    line-height: 1;
}

/* Vector display styles */
.vector-display-matrix {
    display: inline-flex;
    align-items: stretch;
    font-family: var(--font-family-mono);
    font-size: 1rem;
    line-height: 1.2;
}

.matrix-bracket {
    font-size: 3rem;
    font-weight: 100;
    display: flex;
    align-items: center;
    color: var(--color-text);
    user-select: none;
    transform: scaleX(0.4);
    letter-spacing: -0.1em;
}

.matrix-bracket.left {
    margin-right: 4px;
}

.matrix-bracket.right {
    margin-left: 4px;
}

.matrix-content {
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 2px;
    min-width: 50px;
}

.draggable-number {
    cursor: ns-resize;
    user-select: none;
    padding: 2px 6px;
    border-radius: 3px;
    transition: var(--transition-fast);
    display: block;
    background-color: rgba(255, 255, 255, 0.05);
    border: 1px solid transparent;
    font-family: var(--font-family-mono);
    font-size: 0.9rem;
    text-align: center;
    min-height: 20px;
    line-height: 1.2;
}

.draggable-number:hover {
    background-color: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.2);
    transform: scale(1.05);
}

.draggable-number.dragging {
    background-color: var(--color-primary);
    color: white;
    cursor: ns-resize;
    transform: scale(1.1);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.vector-column {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    font-family: var(--font-family-mono);
    font-size: 0.875rem;
}

.vector-bracket {
    font-size: 1.5rem;
    color: var(--color-text);
    font-weight: 300;
    line-height: 1;
}

/* ===========================
   Footer
   =========================== */
.site-footer {
    background: var(--color-background);
    border-top: 1px solid var(--color-border);
    padding: var(--space-3xl) 0;
}

.footer-content {
    text-align: center;
}

.footer-text {
    color: var(--color-text-muted);
    margin-bottom: var(--space-sm);
}

.footer-tech {
    color: var(--color-text-light);
    font-size: var(--font-size-sm);
}

/* Instructions */
.instructions {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    box-shadow: var(--shadow-lg);
}

.instructions h3 {
    font-size: 1rem;
    font-weight: 500;
    margin-bottom: var(--space-md);
    color: var(--color-text);
}

.instructions ul {
    list-style: none;
}

.instructions li {
    font-size: 0.875rem;
    color: var(--color-text-muted);
    padding: var(--space-sm) 0;
    padding-left: var(--space-md);
    position: relative;
}

.instructions li::before {
    content: '•';
    color: var(--color-primary);
    font-weight: bold;
    position: absolute;
    left: 0;
}

/* Responsive Design */
@media (max-width: 1024px) {
    .main-content {
        grid-template-columns: 1fr;
        grid-template-rows: 1fr auto;
    }

    .sidebar {
        flex-direction: row;
        gap: var(--space-md);
    }

    .info-panel,
    .instructions {
        flex: 1;
    }
}

@media (max-width: 768px) {
    .header {
        padding: var(--space-lg) var(--space-md);
    }

    .title {
        font-size: 2rem;
    }

    .main-content {
        padding: var(--space-md);
        gap: var(--space-md);
    }

    .sidebar {
        flex-direction: column;
    }

    .controls {
        flex-direction: column;
        gap: var(--space-sm);
    }
}

@media (max-width: 480px) {
    .title {
        font-size: 1.75rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .info-panel,
    .instructions {
        padding: var(--space-md);
    }
}

/* Scrollbar Styling */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--color-background);
}

::-webkit-scrollbar-thumb {
    background: var(--color-border);
    border-radius: var(--radius-sm);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--color-border-light);
}

/* Loading Animation */
@keyframes pulse {

    0%,
    100% {
        opacity: 1;
    }

    50% {
        opacity: 0.5;
    }
}

.loading {
    animation: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite;
    opacity: 0.7;
    pointer-events: none;
}

@media (prefers-reduced-motion: reduce) {
    .loading {
        animation: none;
    }
}

/* Blog Section */
.blog-section {
    background: var(--color-background);
    padding: var(--space-3xl) 0;
    border-top: 1px solid var(--color-border);
}

.blog-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
    display: flex;
    flex-direction: column;
    gap: var(--space-2xl);
}

.blog-article {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-xl);
    box-shadow: var(--shadow-md);
}

.blog-article h3 {
    color: var(--color-text);
    margin-bottom: var(--space-lg);
    font-size: var(--font-size-xl);
    border-bottom: 2px solid var(--color-primary);
    padding-bottom: var(--space-sm);
}

.blog-article p {
    color: var(--color-text);
    line-height: 1.7;
    margin-bottom: var(--space-md);
}

.blog-article p:last-child {
    margin-bottom: 0;
}

.blog-article ul {
    color: var(--color-text);
    line-height: 1.7;
    margin-bottom: var(--space-md);
    padding-left: var(--space-lg);
}

.blog-article li {
    margin-bottom: var(--space-xs);
}

.blog-article li:last-child {
    margin-bottom: 0;
}

.blog-article a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.blog-article a:hover {
    color: var(--color-primary-light);
    text-decoration: underline;
}

.resource-list {
    list-style-type: none;
    padding-left: 0;
}

.resource-list li {
    background: hsla(var(--color-background-hsl), 0.5);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-md);
    padding: var(--space-md);
    margin-bottom: var(--space-sm);
    transition: background-color var(--transition-fast);
}

.resource-list li:hover {
    background: hsla(var(--color-background-hsl), 0.8);
}

.resource-list a {
    font-weight: 600;
}

.resource-section {
    margin-bottom: var(--space-xl);
}

.resource-section:last-child {
    margin-bottom: 0;
}

.resource-section h4 {
    color: var(--color-text);
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--space-md);
    border-bottom: 1px solid var(--color-border-light);
    padding-bottom: var(--space-xs);
}

.resource-section .resource-list {
    margin-bottom: 0;
}

.resource-section .resource-list li {
    background: hsla(var(--color-background-hsl), 0.3);
    border-left: 3px solid var(--color-primary);
    padding: var(--space-sm) var(--space-md);
    margin-bottom: var(--space-xs);
}

.resource-section .resource-list li:hover {
    background: hsla(var(--color-background-hsl), 0.6);
    border-left-color: var(--color-primary-light);
}

.resource-section .resource-list a {
    display: block;
    font-weight: 500;
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.resource-section .resource-list a:hover {
    color: var(--color-primary-light);
}

.math-display {
    background: hsla(var(--color-background-hsl), 0.7);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-md);
    padding: var(--space-lg);
    margin: var(--space-lg) 0;
    text-align: center;
    overflow-x: auto;
}

.svg-container {
    text-align: center;
    margin: var(--space-lg) 0;
    padding: var(--space-md);
    background: hsla(var(--color-background-hsl), 0.3);
    border-radius: var(--radius-md);
    border: 1px solid var(--color-border-light);
}

.blog-svg {
    max-width: 100%;
    height: auto;
    filter: brightness(0.9);
    transition: filter var(--transition-fast);
}

.blog-svg:hover {
    filter: brightness(1);
}

/* Blog responsive design */
@media (max-width: 1024px) {
    .blog-content {
        max-width: 100%;
        padding: 0 var(--space-md);
    }
}

@media (max-width: 768px) {
    .blog-section {
        padding: var(--space-2xl) var(--space-md);
    }

    .blog-content {
        padding: 0 var(--space-sm);
        gap: var(--space-xl);
    }

    .blog-article {
        padding: var(--space-lg);
    }
}

@media (max-width: 480px) {
    .blog-section {
        padding: var(--space-xl) var(--space-sm);
    }

    .blog-content {
        padding: 0;
    }

    .blog-article {
        padding: var(--space-md);
    }

    .blog-article h3 {
        font-size: var(--font-size-lg);
    }
}