:root {
    --layout-max-width: 1400px;
    --sidebar-width: 280px;
    --bg-dark: #0a0a0f;
    --bg-card: #12121a;
    --bg-code: #1a1a2e;
    --neon-cyan: #00f5ff;
    --neon-magenta: #ff00ff;
    --neon-purple: #b366ff;
    --text-primary: #ffffff;
    --text-secondary: #a0a0b0;
    --border-color: #2a2a3a;
    --success-green: #4ec9b0;
    --warning-yellow: #dcdcaa;
}

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

body {
    font-family: 'Space Grotesk', sans-serif;
    background: var(--bg-dark);
    color: var(--text-primary);
    line-height: 1.7;
    min-height: 100vh;
}

/* Grid background */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        linear-gradient(90deg, rgba(0,245,255,0.03) 1px, transparent 1px),
        linear-gradient(rgba(0,245,255,0.03) 1px, transparent 1px);
    background-size: 50px 50px;
    pointer-events: none;
    z-index: -1;
}

/* Header */
.header {
    background: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 2rem;
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    max-width: var(--layout-max-width);
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.header-brand {
    display: flex;
    align-items: center;
    gap: 1rem;
    text-decoration: none;
    color: var(--text-primary);
}

.header-brand:hover {
    color: var(--neon-cyan);
}

.header-logo {
    height: 32px;
    width: auto;
}

.logo-light {
    display: none;
}

html[data-theme="light"] .logo-dark {
    display: none;
}

html[data-theme="light"] .logo-light {
    display: block;
}

.header-title {
    font-size: 1.25rem;
    font-weight: 600;
    background: linear-gradient(135deg, var(--neon-cyan), var(--neon-magenta));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.header-nav {
    display: flex;
    gap: 0.5rem;
}

.nav-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.875rem;
    transition: all 0.2s ease;
    cursor: pointer;
    font-family: inherit;
}

.nav-btn:hover:not(:disabled) {
    border-color: var(--neon-cyan);
    color: var(--neon-cyan);
}

.nav-btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

/* Sidebar */
.layout {
    display: flex;
    max-width: var(--layout-max-width);
    margin: 0 auto;
}

.sidebar {
    width: var(--sidebar-width);
    background: var(--bg-card);
    border-right: 1px solid var(--border-color);
    height: calc(100vh - 65px);
    position: sticky;
    top: 65px;
    overflow-y: auto;
    flex-shrink: 0;
}

.sidebar-section {
    padding: 1rem;
}

.sidebar-title {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
    padding: 0 0.5rem;
}

.step-link {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.625rem 0.75rem;
    border-radius: 6px;
    text-decoration: none;
    color: var(--text-secondary);
    font-size: 0.875rem;
    transition: all 0.2s ease;
    margin-bottom: 0.25rem;
}

.step-link:hover {
    background: rgba(0,245,255,0.1);
    color: var(--text-primary);
}

.step-link.active {
    background: linear-gradient(135deg, rgba(0,245,255,0.2), rgba(255,0,255,0.2));
    color: var(--text-primary);
    border-left: 3px solid var(--neon-cyan);
}

.step-number {
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--border-color);
    border-radius: 6px;
    font-size: 0.75rem;
    font-weight: 600;
    font-family: 'JetBrains Mono', monospace;
    flex-shrink: 0;
}

.step-link.active .step-number {
    background: linear-gradient(135deg, var(--neon-cyan), var(--neon-magenta));
    color: var(--bg-dark);
}

/* Main Content */
.main {
    flex: 1;
    min-width: 0;
    padding: 2rem 3rem;
}

.content {
    max-width: 800px;
    margin: 0 auto;
}

/* Loading */
.loading {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 300px;
    color: var(--text-secondary);
}

.loading::after {
    content: '';
    width: 32px;
    height: 32px;
    border: 3px solid var(--border-color);
    border-top-color: var(--neon-cyan);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin-left: 1rem;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Markdown Styles */
.markdown h1 {
    font-size: 2.25rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    background: linear-gradient(135deg, var(--neon-cyan), var(--neon-magenta));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.3;
}

.markdown h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin: 2.5rem 0 1rem;
    color: var(--neon-cyan);
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
}

.markdown h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin: 2rem 0 0.75rem;
    color: var(--neon-magenta);
}

.markdown h4 {
    font-size: 1.1rem;
    font-weight: 600;
    margin: 1.5rem 0 0.5rem;
    color: var(--text-primary);
}

.markdown p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

.markdown a {
    color: var(--neon-cyan);
    text-decoration: none;
}

.markdown a:hover {
    text-decoration: underline;
}

.markdown strong {
    color: var(--text-primary);
    font-weight: 600;
}

.markdown ul, .markdown ol {
    margin: 1rem 0 1.5rem 1.5rem;
    color: var(--text-secondary);
}

.markdown li {
    margin-bottom: 0.5rem;
}

.markdown li::marker {
    color: var(--neon-cyan);
}

/* Checkboxes */
.markdown input[type="checkbox"] {
    appearance: none;
    width: 18px;
    height: 18px;
    border: 2px solid var(--border-color);
    border-radius: 4px;
    margin-right: 0.5rem;
    vertical-align: middle;
    position: relative;
    cursor: pointer;
}

.markdown input[type="checkbox"]:checked {
    background: var(--neon-cyan);
    border-color: var(--neon-cyan);
}

.markdown input[type="checkbox"]:checked::after {
    content: '\2713';
    position: absolute;
    color: var(--bg-dark);
    font-size: 12px;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

/* Code blocks */
.markdown code {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.875em;
}

.markdown :not(pre) > code {
    background: var(--bg-code);
    padding: 0.2em 0.4em;
    border-radius: 4px;
    color: var(--warning-yellow);
}

.markdown pre {
    background: var(--bg-code);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1.25rem;
    overflow-x: auto;
    margin: 1.5rem 0;
}

.code-block-wrapper {
    position: relative;
    margin: 1.5rem 0;
}

.code-block-wrapper pre {
    margin: 0;
}

.diagram-block-wrapper pre {
    background: transparent;
    border: 0;
    border-radius: 0;
    padding: 0;
}

.diagram-block-wrapper pre,
.diagram-block-wrapper pre code {
    font-family: 'Cascadia Mono', 'Cascadia Code', Consolas, 'Lucida Console', monospace;
    font-size: 15px;
    line-height: 1.35;
    letter-spacing: 0;
    font-variant-ligatures: none;
    font-feature-settings: 'liga' 0, 'calt' 0;
    text-rendering: optimizeSpeed;
    white-space: pre;
    word-break: normal;
    overflow-wrap: normal;
}

.diagram-block-wrapper pre code {
    display: block;
    width: max-content;
    min-width: 100%;
    background: transparent;
}

.copy-code-btn {
    position: absolute;
    top: 0.5rem;
    right: 0.5rem;
    z-index: 1;
    border: none;
    background: rgba(0, 0, 0, 0.55);
    color: #fff;
    border-radius: 8px;
    width: 32px;
    height: 32px;
    padding: 0;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: opacity 0.2s, background 0.2s, box-shadow 0.2s;
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
}

.code-block-wrapper:hover .copy-code-btn,
.code-block-wrapper:focus-within .copy-code-btn,
.copy-code-btn[data-state="success"],
.copy-code-btn[data-state="error"] {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
}

.copy-code-btn::before {
    content: '';
    width: 1rem;
    height: 1rem;
    display: block;
    background-color: currentColor;
    -webkit-mask-repeat: no-repeat;
    -webkit-mask-position: center;
    -webkit-mask-size: contain;
    -webkit-mask-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='black' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Crect x='9' y='9' width='13' height='13' rx='2' ry='2'/%3E%3Cpath d='M5 15H4a2 2 0 0 1-2-2V4a2 2 0 0 1 2-2h9a2 2 0 0 1 2 2v1'/%3E%3C/svg%3E");
    mask-repeat: no-repeat;
    mask-position: center;
    mask-size: contain;
    mask-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='black' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Crect x='9' y='9' width='13' height='13' rx='2' ry='2'/%3E%3Cpath d='M5 15H4a2 2 0 0 1-2-2V4a2 2 0 0 1 2-2h9a2 2 0 0 1 2 2v1'/%3E%3C/svg%3E");
}

.copy-code-btn:hover,
.copy-code-btn:focus-visible {
    background: rgba(0, 0, 0, 0.72);
    color: var(--neon-cyan);
    box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.14);
    outline: none;
}

.copy-code-btn[data-state="success"] {
    color: var(--success-green);
    background: rgba(0, 0, 0, 0.72);
}

.copy-code-btn[data-state="success"]::before {
    -webkit-mask-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='black' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M20 6 9 17l-5-5'/%3E%3C/svg%3E");
    mask-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='black' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M20 6 9 17l-5-5'/%3E%3C/svg%3E");
}

.copy-code-btn[data-state="error"] {
    color: var(--warning-yellow);
    background: rgba(0, 0, 0, 0.72);
}

.copy-code-btn[data-state="error"]::before {
    -webkit-mask-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='black' stroke-width='2.25' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M12 9v4'/%3E%3Cpath d='M12 17h.01'/%3E%3Cpath d='M10.29 3.86 1.82 18a2 2 0 0 0 1.71 3h16.94a2 2 0 0 0 1.71-3L13.71 3.86a2 2 0 0 0-3.42 0z'/%3E%3C/svg%3E");
    mask-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='black' stroke-width='2.25' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M12 9v4'/%3E%3Cpath d='M12 17h.01'/%3E%3Cpath d='M10.29 3.86 1.82 18a2 2 0 0 0 1.71 3h16.94a2 2 0 0 0 1.71-3L13.71 3.86a2 2 0 0 0-3.42 0z'/%3E%3C/svg%3E");
}

.mermaid-block {
    background: var(--bg-code);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1.25rem;
    margin: 1.5rem 0;
    overflow-x: auto;
}

.mermaid-block svg {
    display: block;
    max-width: 100%;
    height: auto;
    margin: 0 auto;
}

.mermaid-block.mermaid-error {
    font-family: 'JetBrains Mono', monospace;
    white-space: pre;
    color: var(--warning-yellow);
}

.markdown pre code {
    color: var(--text-primary);
    background: none;
    padding: 0;
}

/* Blockquotes / Tips */
.markdown blockquote {
    background: var(--bg-card);
    border-left: 4px solid var(--neon-cyan);
    border-radius: 0 8px 8px 0;
    padding: 1rem 1.25rem;
    margin: 1.5rem 0;
}

.markdown blockquote p {
    margin: 0;
    color: var(--text-secondary);
}

.markdown blockquote p:first-child {
    font-weight: 600;
    color: var(--neon-cyan);
}

/* Images */
.markdown img {
    max-width: 100%;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    margin: 1.5rem 0;
}

.image-enlarge-wrap {
    position: relative;
    display: inline-block;
    margin: 1.5rem 0;
}

.image-enlarge-wrap img {
    display: block;
    margin: 0;
    cursor: default;
}

.image-enlarge-btn {
    position: absolute;
    top: 0.5rem;
    right: 0.5rem;
    width: 32px;
    height: 32px;
    background: rgba(0, 0, 0, 0.55);
    color: #fff;
    border: none;
    border-radius: 8px;
    padding: 0;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.2s, background 0.2s, color 0.2s, box-shadow 0.2s;
}

.image-enlarge-btn::before {
    content: "";
    width: 18px;
    height: 18px;
    display: block;
    background-color: currentColor;
    -webkit-mask-repeat: no-repeat;
    -webkit-mask-position: center;
    -webkit-mask-size: contain;
    -webkit-mask-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='black' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='15 3 21 3 21 9'/%3E%3Cpolyline points='9 21 3 21 3 15'/%3E%3Cline x1='21' y1='3' x2='14' y2='10'/%3E%3Cline x1='3' y1='21' x2='10' y2='14'/%3E%3C/svg%3E");
    mask-repeat: no-repeat;
    mask-position: center;
    mask-size: contain;
    mask-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='black' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='15 3 21 3 21 9'/%3E%3Cpolyline points='9 21 3 21 3 15'/%3E%3Cline x1='21' y1='3' x2='14' y2='10'/%3E%3Cline x1='3' y1='21' x2='10' y2='14'/%3E%3C/svg%3E");
}

.image-enlarge-wrap:hover .image-enlarge-btn,
.image-enlarge-wrap:focus-within .image-enlarge-btn {
    opacity: 1;
    visibility: visible;
}

.image-enlarge-btn:hover,
.image-enlarge-btn:focus-visible {
    background: rgba(0, 0, 0, 0.72);
    color: var(--neon-cyan);
    box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.14);
    outline: none;
}

/* Lightbox */
.lightbox-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.9);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.25s, visibility 0.25s;
    cursor: zoom-out;
}

.lightbox-overlay.active {
    opacity: 1;
    visibility: visible;
}

.lightbox-img {
    max-width: 92vw;
    max-height: 92vh;
    border-radius: 8px;
    box-shadow: 0 0 60px rgba(0, 0, 0, 0.6);
    object-fit: contain;
}

.lightbox-close {
    position: absolute;
    top: 1rem;
    right: 1.5rem;
    background: none;
    border: none;
    color: #fff;
    font-size: 2.5rem;
    cursor: pointer;
    line-height: 1;
    opacity: 0.7;
    transition: opacity 0.2s;
}

.lightbox-close:hover {
    opacity: 1;
}

/* Tables */
.markdown table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
}

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

.markdown th {
    background: var(--bg-card);
    color: var(--text-primary);
    font-weight: 600;
}

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

.markdown tr:hover td {
    background: rgba(0,245,255,0.05);
}

/* Horizontal rule */
.markdown hr {
    border: none;
    border-top: 1px solid var(--border-color);
    margin: 2.5rem 0;
}

/* Navigation Footer */
.nav-footer {
    display: flex;
    justify-content: space-between;
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
}

.nav-footer-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 500;
    transition: all 0.2s ease;
}

.nav-footer-btn:hover {
    border-color: var(--neon-cyan);
    transform: translateY(-2px);
}

.nav-footer-btn.disabled {
    opacity: 0.4;
    pointer-events: none;
}

/* Mobile */
@media (max-width: 900px) {
    .sidebar {
        display: none;
    }

    .main {
        padding: 1.5rem;
    }

    .header-title {
        display: none;
    }
}

@media (min-width: 1200px) {
    .header-content {
        padding-left: 1rem;
    }
}

@media (max-width: 640px) {
    .copy-code-btn {
        top: 0.5rem;
        right: 0.5rem;
        padding: 0.3rem 0.65rem;
    }

    .markdown pre {
        padding-top: 3rem;
    }
}