/* ========================================
   CSS Reset & Base Styles
   ======================================== */

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

:root {
    /* Resend-inspired Color Palette */
    --color-bg-primary: #000000;
    --color-bg-secondary: #0a0a0a;
    --color-bg-tertiary: #141414;
    --color-bg-code: #0f0f0f;

    --color-text-primary: #ffffff;
    --color-text-secondary: #a1a1a1;
    --color-text-tertiary: #737373;

    --color-accent: #00a3ff;
    --color-accent-hover: #0091e6;

    --color-border: #262626;
    --color-border-light: #1f1f1f;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    --spacing-3xl: 6rem;

    /* Typography */
    --font-sans: 'Geist Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Courier New', monospace;

    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    --font-size-4xl: 2.5rem;
    --font-size-5xl: 3.5rem;

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 200ms ease;
    --transition-slow: 300ms ease;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    background: var(--color-bg-primary);
    color: var(--color-text-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ========================================
   Top Navigation
   ======================================== */

.top-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: var(--spacing-md) var(--spacing-lg);
    background: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
}

.nav-home-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: var(--color-bg-tertiary);
    color: var(--color-text-primary);
    text-decoration: none;
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-weight: 500;
    transition: all var(--transition-base);
    border: 1px solid var(--color-border);
}

.nav-home-btn:hover {
    background: var(--color-bg-secondary);
    border-color: var(--color-accent);
    color: var(--color-accent);
}

.nav-home-btn svg {
    width: 16px;
    height: 16px;
}

/* ========================================
   Container & Layout
   ======================================== */

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* ========================================
   Hero Section
   ======================================== */

.hero {
    position: relative !important;
    min-height: 100vh !important;
    display: flex !important;
    align-items: center !important;
    justify-content: center !important;
    background: radial-gradient(ellipse at top, rgba(0, 163, 255, 0.15) 0%, transparent 50%),
                linear-gradient(180deg, var(--color-bg-primary) 0%, var(--color-bg-secondary) 100%) !important;
    border-bottom: 1px solid var(--color-border) !important;
    overflow: hidden !important;
}

.hero-content {
    text-align: center !important;
    max-width: 100% !important;
    margin: 0 auto !important;
    display: flex !important;
    flex-direction: column !important;
    align-items: center !important;
    width: 100% !important;
    padding: 0 var(--spacing-lg) !important;
}

.hero-title {
    font-size: clamp(2rem, 6vw, 4rem) !important;
    font-weight: 700 !important;
    margin-bottom: var(--spacing-lg) !important;
    letter-spacing: -0.02em !important;
    line-height: 1.15 !important;
    background: linear-gradient(135deg, var(--color-text-primary) 0%, var(--color-text-secondary) 100%) !important;
    -webkit-background-clip: text !important;
    -webkit-text-fill-color: transparent !important;
    background-clip: text !important;
    animation: fadeInUp 0.8s ease-out !important;
}

.hero-code-window {
    width: 100% !important;
    max-width: 900px !important;
    background: var(--color-bg-code) !important;
    border: 1px solid var(--color-border) !important;
    border-radius: var(--radius-lg) !important;
    overflow: hidden !important;
    margin-bottom: var(--spacing-lg) !important;
    animation: fadeInUp 0.8s ease-out 0.2s backwards !important;
}

.code-window-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1rem;
    background: var(--color-bg-tertiary);
    border-bottom: 1px solid var(--color-border);
}

.window-controls {
    display: flex;
    gap: 0.5rem;
}

.control {
    width: 12px;
    height: 12px;
    border-radius: 50%;
}

.control.close {
    background: #ff5f56;
}

.control.minimize {
    background: #ffbd2e;
}

.control.maximize {
    background: #27c93f;
}

.window-title {
    font-family: var(--font-mono);
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
}

.code-window-content {
    padding: 1.5rem;
    min-height: 320px;
    text-align: left;
}

.code-window-content pre {
    margin: 0;
    min-height: 320px;
    text-align: left;
}

.code-window-content code {
    font-family: var(--font-mono);
    font-size: var(--font-size-sm);
    line-height: 1.8;
    color: var(--color-text-primary);
    display: block;
    white-space: pre;
    min-height: 320px;
    text-align: left;
}

.hero-subtitle {
    font-size: var(--font-size-xl);
    color: var(--color-text-secondary);
    margin-bottom: 0.75rem;
    animation: fadeInUp 0.8s ease-out 0.4s backwards;
}

.hero-cta {
    display: flex;
    gap: var(--spacing-sm);
    animation: fadeInUp 0.8s ease-out 0.6s backwards;
}

.cta-btn {
    padding: 0.875rem 2rem;
    font-size: var(--font-size-base);
    font-weight: 500;
    text-decoration: none;
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
    border: 1px solid var(--color-border);
}

.cta-btn.primary {
    background: #ffffff;
    color: #000000;
    border-color: #ffffff;
}

.cta-btn.primary:hover {
    background: var(--color-text-secondary);
    border-color: var(--color-text-secondary);
}

.scroll-indicator {
    position: absolute;
    bottom: var(--spacing-xl);
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--color-text-tertiary);
    opacity: 0;
    animation: fadeInCenter 1s ease-out 1s forwards, bounce 2s ease-in-out 2s infinite;
}

.scroll-arrow {
    color: #ffffff;
}

/* ========================================
   Features Section
   ======================================== */

.features-section {
    padding: var(--spacing-3xl) 0;
    background: var(--color-bg-secondary);
}

.feature-section {
    margin-bottom: var(--spacing-3xl);
}

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

.feature-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.feature-number {
    font-family: var(--font-mono);
    font-size: var(--font-size-sm);
    color: #ff5722;
    font-weight: 600;
}

.feature-title {
    font-size: var(--font-size-3xl);
    font-weight: 600;
    letter-spacing: -0.01em;
}

.feature-description {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    line-height: 1.8;
    margin-bottom: var(--spacing-xl);
    max-width: 900px;
}

.feature-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    align-items: start;
}

.feature-code {
    background: var(--color-bg-code);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.code-header {
    padding: 0.75rem 1rem;
    background: var(--color-bg-tertiary);
    border-bottom: 1px solid var(--color-border);
}

.code-label {
    font-family: var(--font-mono);
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
}

.feature-code pre {
    margin: 0;
    padding: 1.5rem;
    overflow-x: auto;
}

.feature-code code {
    font-family: var(--font-mono);
    font-size: var(--font-size-sm);
    line-height: 1.8;
    color: var(--color-text-primary);
}

/* Code Syntax Highlighting */
.code-comment {
    color: #6a9955;
}

.code-tag {
    color: #ff5722;
}

.code-attr {
    color: #9cdcfe;
}

.code-string {
    color: #ce9178;
}

/* Interactive Demo */
.interactive-demo {
    background: var(--color-bg-code);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
}

.demo-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
}

.demo-controls {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.demo-controls input {
    padding: 0.75rem 1rem;
    background: var(--color-bg-primary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    color: var(--color-text-primary);
    font-family: var(--font-sans);
    font-size: var(--font-size-base);
}

.demo-controls input:focus {
    outline: none;
    border-color: #ff5722;
}

.interactive-btn {
    padding: 0.75rem 1.5rem;
    background: #ffffff;
    color: #000000;
    border: 1px solid #ffffff;
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-base);
    font-family: var(--font-sans);
}

.interactive-btn:hover {
    background: var(--color-text-secondary);
    border-color: var(--color-text-secondary);
}

.demo-output {
    background: var(--color-bg-primary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    min-height: 100px;
}

.demo-output:empty::before {
    content: 'Output will appear here...';
    color: var(--color-text-tertiary);
    font-style: italic;
}

/* Semantic Visualization */
.semantic-visualization {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.sem-box {
    padding: var(--spacing-sm);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.sem-box strong {
    font-family: var(--font-mono);
    font-size: var(--font-size-base);
    color: #ff5722;
}

.sem-box span {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
}

.sem-header {
    border-color: #ff5722;
}

.sem-main {
    border-color: #00a3ff;
}

.sem-aside {
    border-color: #9c27b0;
}

.sem-footer {
    border-color: #4caf50;
}

/* Forms */
.demo-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

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

.form-group label {
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-text-secondary);
}

.form-group input {
    padding: 0.75rem 1rem;
    background: var(--color-bg-primary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    color: var(--color-text-primary);
    font-family: var(--font-sans);
    font-size: var(--font-size-base);
}

.form-group input:focus {
    outline: none;
    border-color: #ff5722;
}

/* Tables */
.demo-table {
    width: 100%;
    border-collapse: collapse;
    font-size: var(--font-size-sm);
}

.demo-table thead {
    background: var(--color-bg-tertiary);
}

.demo-table th,
.demo-table td {
    padding: 0.75rem 1rem;
    text-align: left;
    border: 1px solid var(--color-border);
}

.demo-table th {
    font-weight: 600;
    color: var(--color-text-primary);
}

.demo-table td {
    color: var(--color-text-secondary);
}

/* Lists */
#demoUl,
#demoOl {
    margin-left: 1.5rem;
}

#demoUl li,
#demoOl li {
    margin-bottom: 0.5rem;
    color: var(--color-text-secondary);
}

/* ========================================
   Playground Section
   ======================================== */

.playground-section {
    padding: var(--spacing-3xl) 0;
    background: var(--color-bg-primary);
    border-top: 1px solid var(--color-border);
}

.section-title {
    font-size: var(--font-size-4xl);
    font-weight: 600;
    text-align: center;
    margin-bottom: var(--spacing-sm);
    letter-spacing: -0.01em;
}

.section-description {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    text-align: center;
    margin-bottom: var(--spacing-2xl);
}

.playground {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
}

.playground-editor,
.playground-preview {
    background: var(--color-bg-code);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.editor-header,
.preview-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 0.75rem 1rem;
    background: var(--color-bg-tertiary);
    border-bottom: 1px solid var(--color-border);
}

.preview-controls {
    display: flex;
    gap: 0.5rem;
}

.preview-control {
    width: 12px;
    height: 12px;
    border-radius: 50%;
}

.preview-control.close {
    background: #ff5f56;
}

.preview-control.minimize {
    background: #ffbd2e;
}

.preview-control.maximize {
    background: #27c93f;
}

.browser-url-bar {
    flex: 1;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--color-bg-primary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    padding: 0.5rem 0.75rem;
}

.lock-icon {
    color: var(--color-text-tertiary);
    flex-shrink: 0;
}

.url-text {
    font-family: var(--font-mono);
    font-size: var(--font-size-xs);
    color: var(--color-text-secondary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.editor-label,
.preview-label {
    font-family: var(--font-mono);
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
}

.run-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: #ffffff;
    color: #000000;
    border: 1px solid #ffffff;
    border-radius: var(--radius-sm);
    font-size: var(--font-size-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-base);
    font-family: var(--font-sans);
}

.run-btn:hover {
    background: var(--color-text-secondary);
    border-color: var(--color-text-secondary);
}

.code-editor {
    width: 100%;
    height: 500px;
    padding: 1.5rem;
    background: var(--color-bg-code);
    border: none;
    color: var(--color-text-primary);
    font-family: var(--font-mono);
    font-size: var(--font-size-sm);
    line-height: 1.6;
    resize: vertical;
    outline: none;
}

.code-editor::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

.code-editor::-webkit-scrollbar-track {
    background: var(--color-bg-primary);
}

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

.code-editor::-webkit-scrollbar-thumb:hover {
    background: var(--color-text-tertiary);
}

.html-preview {
    width: 100%;
    height: 500px;
    background: #ffffff;
    border: none;
}

/* ========================================
   Footer
   ======================================== */

.footer {
    padding: var(--spacing-2xl) 0;
    background: var(--color-bg-secondary);
    border-top: 1px solid var(--color-border);
}

.footer-content {
    text-align: center;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.footer-copyright {
    font-size: var(--font-size-sm);
    color: var(--color-text-tertiary);
}

.footer-powered {
    font-size: var(--font-size-sm);
    color: var(--color-text-tertiary);
}

.footer-link {
    color: var(--color-text-secondary);
    text-decoration: none;
    transition: color var(--transition-base);
}

.footer-link:hover {
    color: var(--color-text-primary);
}

/* ========================================
   Animations
   ======================================== */

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInCenter {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes bounce {
    0%, 100% {
        transform: translateX(-50%) translateY(0);
    }
    50% {
        transform: translateX(-50%) translateY(-10px);
    }
}

/* ========================================
   Responsive Design
   ======================================== */

@media (max-width: 1024px) {
    .feature-grid,
    .playground {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    :root {
        --font-size-3xl: 1.75rem;
        --font-size-4xl: 2rem;
        --font-size-5xl: 2.5rem;
    }

    .top-nav {
        padding: var(--spacing-sm) var(--spacing-md);
    }

    .top-nav img {
        max-width: 100px !important;
    }

    .nav-home-btn {
        padding: 0;
        font-size: 0;
        width: 36px;
        height: 36px;
        min-width: 36px;
        min-height: 36px;
        display: flex !important;
        align-items: center;
        justify-content: center;
        gap: 0;
    }

    .nav-home-btn svg {
        width: 18px;
        height: 18px;
        flex-shrink: 0;
    }

    .hero {
        min-height: auto;
        padding: var(--spacing-3xl) 0;
    }

    .hero-content {
        display: contents;
    }

    .hero-title {
        order: 1;
        margin-bottom: var(--spacing-lg) !important;
    }

    .hero-code-window {
        order: 2;
        margin-bottom: var(--spacing-lg) !important;
    }

    .hero-subtitle {
        order: 3;
    }

    .hero-cta {
        order: 4;
    }

    .scroll-indicator {
        display: none;
    }

    .code-window-content {
        padding: 1rem;
    }

    .code-window-content pre,
    .code-window-content code {
        text-align: left;
    }

    .feature-section {
        margin-bottom: var(--spacing-2xl);
    }

    .feature-header {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing-xs);
    }

    .code-editor,
    .html-preview {
        min-height: 350px;
    }

    /* Mobile nuclear reset for alignment */
    .feature-content,
    .feature-grid,
    .feature-code,
    .interactive-demo {
        all: unset !important;
        display: block !important;
        width: 100% !important;
        box-sizing: border-box !important;
    }

    .feature-content {
        margin-bottom: var(--spacing-md) !important;
    }

    .feature-description {
        font-size: var(--font-size-lg) !important;
        color: var(--color-text-secondary) !important;
        line-height: 1.8 !important;
        margin-bottom: var(--spacing-lg) !important;
    }

    .feature-grid {
        display: flex !important;
        flex-direction: column !important;
        gap: var(--spacing-md) !important;
    }

    .feature-code {
        background: var(--color-bg-code) !important;
        border: 1px solid var(--color-border) !important;
        border-radius: var(--radius-lg) !important;
        overflow: hidden !important;
        margin-bottom: var(--spacing-md) !important;
    }

    .interactive-demo {
        background: var(--color-bg-code) !important;
        border: 1px solid var(--color-border) !important;
        border-radius: var(--radius-lg) !important;
        padding: var(--spacing-md) !important;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-md);
    }
}

/* ========================================
   Accessibility
   ======================================== */

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

*:focus-visible {
    outline: 2px solid #ff5722;
    outline-offset: 2px;
}

::selection {
    background: #ff5722;
    color: var(--color-text-primary);
}