/* ===== Design Tokens ===== */
:root {
    --color-primary: #087ea4;
    --color-primary-dark: #065d7e;
    --color-primary-light: #e6f7ff;
    --color-bg: #ffffff;
    --color-bg-secondary: #f6f7f9;
    --color-bg-wash: #f0f2f5;
    --color-bg-code: #1e1e1e;
    --color-text: #23272f;
    --color-text-secondary: #5e687e;
    --color-border: #e4e6eb;
    --color-link: #087ea4;
    --color-note: #087ea4;
    --color-warning: #b35900;
    --color-tip: #5b2f8e;

    --sidebar-width: 280px;
    --header-height: 64px;
    --content-max-width: 780px;
    --content-padding: 40px;

    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    --font-mono: 'Source Code Pro', Menlo, Consolas, Monaco, 'Courier New', monospace;
    --font-size-base: 16px;
    --line-height-base: 1.75;

    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
}

/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    margin: 0;
    padding: 0;
    font-family: var(--font-sans);
    font-size: var(--font-size-base);
    line-height: var(--line-height-base);
    color: var(--color-text);
    background: var(--color-bg);
    -webkit-font-smoothing: antialiased;
}
a { color: var(--color-link); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; }

/* ===== Loading ===== */
.loading {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    color: var(--color-text-secondary);
    font-size: 18px;
}

/* ===== Layout ===== */
.layout {
    min-height: 100vh;
}
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    padding: 0 24px;
    z-index: 100;
}
.header-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 20px;
    font-weight: 700;
    color: var(--color-primary);
    text-decoration: none;
    margin-right: 32px;
}
.header-logo:hover { text-decoration: none; }
.header-nav {
    display: flex;
    align-items: center;
    gap: 4px;
    flex: 1;
}
.header-nav a {
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    color: var(--color-text-secondary);
    font-size: 15px;
    font-weight: 500;
    transition: background 0.15s, color 0.15s;
}
.header-nav a:hover {
    background: var(--color-bg-secondary);
    color: var(--color-text);
    text-decoration: none;
}
.header-nav a.active {
    color: var(--color-primary);
    background: var(--color-primary-light);
}
.header-github {
    margin-left: auto;
    color: var(--color-text-secondary);
    font-size: 14px;
    font-weight: 500;
}
.hamburger {
    display: none;
    background: none;
    border: none;
    font-size: 24px;
    cursor: pointer;
    padding: 8px;
    color: var(--color-text);
    margin-right: 8px;
}

.layout-body {
    display: flex;
    padding-top: var(--header-height);
    min-height: 100vh;
}

/* ===== Sidebar ===== */
.sidebar {
    position: fixed;
    top: var(--header-height);
    left: 0;
    bottom: 0;
    width: var(--sidebar-width);
    overflow-y: auto;
    padding: 24px 16px;
    border-right: 1px solid var(--color-border);
    background: var(--color-bg);
    z-index: 50;
}
.sidebar-section {
    margin-bottom: 24px;
}
.sidebar-section-title {
    font-size: 12px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--color-text-secondary);
    padding: 8px 12px;
    margin: 0;
}
.sidebar-link {
    display: block;
    padding: 6px 12px;
    border-radius: var(--radius-sm);
    color: var(--color-text-secondary);
    font-size: 14px;
    font-weight: 500;
    transition: background 0.15s, color 0.15s;
    line-height: 1.5;
}
.sidebar-link:hover {
    background: var(--color-bg-secondary);
    color: var(--color-text);
    text-decoration: none;
}
.sidebar-link.active {
    background: var(--color-primary-light);
    color: var(--color-primary);
    font-weight: 600;
}

/* ===== Main Content ===== */
.content {
    flex: 1;
    margin-left: var(--sidebar-width);
    padding: var(--content-padding);
    max-width: calc(var(--content-max-width) + var(--content-padding) * 2);
}
.content h1 {
    font-size: 36px;
    font-weight: 700;
    line-height: 1.2;
    margin: 0 0 8px;
    color: var(--color-text);
}
.content h2 {
    font-size: 24px;
    font-weight: 700;
    line-height: 1.3;
    margin: 48px 0 16px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--color-border);
    color: var(--color-text);
}
.content h3 {
    font-size: 20px;
    font-weight: 600;
    margin: 32px 0 12px;
    color: var(--color-text);
}
.content h4 {
    font-size: 17px;
    font-weight: 600;
    margin: 24px 0 8px;
}
.content p {
    margin: 0 0 16px;
    color: var(--color-text);
}
.content ul, .content ol {
    padding-left: 24px;
    margin: 0 0 16px;
}
.content li {
    margin-bottom: 6px;
}
.content .subtitle {
    font-size: 18px;
    color: var(--color-text-secondary);
    margin: 0 0 32px;
    line-height: 1.5;
}
.content code {
    background: var(--color-bg-wash);
    padding: 2px 6px;
    border-radius: 3px;
    font-family: var(--font-mono);
    font-size: 0.9em;
}

/* ===== Code Blocks ===== */
.code-block {
    margin: 0 0 24px;
    border-radius: var(--radius-md);
    overflow: hidden;
}
.code-block pre {
    margin: 0;
    padding: 20px 24px;
    background: var(--color-bg-code) !important;
    border-radius: var(--radius-md);
    overflow-x: auto;
    font-size: 14px;
    line-height: 1.6;
}
.code-block pre code {
    background: none;
    padding: 0;
    font-family: var(--font-mono);
    font-size: 14px;
    color: #d4d4d4;
}

/* ===== Code Tabs ===== */
.code-tabs {
    margin: 0 0 24px;
    border-radius: var(--radius-md);
    overflow: hidden;
    border: 1px solid #383838;
}
.code-tabs-header {
    display: flex;
    background: #2d2d2d;
    border-bottom: 1px solid #383838;
}
.code-tab-btn {
    padding: 8px 20px;
    background: transparent;
    border: none;
    color: #999;
    font-family: var(--font-sans);
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    border-bottom: 2px solid transparent;
    transition: color 0.15s, border-color 0.15s;
}
.code-tab-btn:hover {
    color: #ccc;
}
.code-tab-btn.active {
    color: #fff;
    border-bottom-color: var(--color-primary);
}
.code-tabs .code-block {
    margin: 0;
}
.code-tabs .code-block pre {
    border-radius: 0;
    border: none;
}

/* ===== Live Demo ===== */
.live-demo {
    margin: 0 0 24px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    overflow: hidden;
}
.live-demo-label {
    font-size: 12px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--color-text-secondary);
    background: var(--color-bg-secondary);
    padding: 8px 16px;
    border-bottom: 1px solid var(--color-border);
}
.live-demo-content {
    padding: 24px;
    background: var(--color-bg);
}
.live-demo-content button {
    background: var(--color-primary);
    color: white;
    border: none;
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 14px;
    font-family: var(--font-sans);
    transition: background 0.15s;
    margin: 4px;
}
.live-demo-content button:hover { background: var(--color-primary-dark); }
.live-demo-content input[type="text"],
.live-demo-content input[type="number"] {
    padding: 8px 12px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-size: 14px;
    font-family: var(--font-sans);
    outline: none;
    transition: border-color 0.15s;
}
.live-demo-content input:focus { border-color: var(--color-primary); }

/* ===== Callouts ===== */
.callout {
    padding: 16px 20px;
    border-radius: var(--radius-md);
    margin: 0 0 24px;
    border-left: 4px solid;
}
.callout-title {
    font-weight: 700;
    font-size: 14px;
    margin-bottom: 8px;
}
.callout p { margin: 0; }
.callout p + p { margin-top: 8px; }
.callout-note {
    background: #e6f7ff;
    border-color: var(--color-note);
}
.callout-note .callout-title { color: var(--color-note); }
.callout-pitfall {
    background: #fff7e6;
    border-color: var(--color-warning);
}
.callout-pitfall .callout-title { color: var(--color-warning); }
.callout-deepdive {
    background: #f3ecff;
    border-color: var(--color-tip);
}
.callout-deepdive .callout-title { color: var(--color-tip); }

/* ===== Project Initializer ===== */
.project-initializer {
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    background: var(--color-bg);
    margin: 0 0 32px;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}
.pi-header {
    background: linear-gradient(135deg, var(--color-primary), #1a9bc7);
    padding: 28px 32px 20px;
    color: white;
}
.pi-header h2 {
    margin: 0 0 8px;
    font-size: 22px;
    font-weight: 700;
    color: white;
    border: none;
    padding: 0;
}
.pi-header p {
    margin: 0;
    font-size: 15px;
    color: rgba(255, 255, 255, 0.9);
    line-height: 1.5;
}
.pi-language-toggle {
    display: flex;
    padding: 16px 32px 0;
    gap: 0;
}
.pi-lang-btn {
    flex: 1;
    padding: 10px 20px;
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    color: var(--color-text-secondary);
    font-family: var(--font-sans);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.15s, color 0.15s, border-color 0.15s;
}
.pi-lang-btn:first-child {
    border-radius: var(--radius-sm) 0 0 var(--radius-sm);
    border-right: none;
}
.pi-lang-btn:last-child {
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.pi-lang-btn:hover {
    color: var(--color-text);
}
.pi-lang-btn.active {
    background: var(--color-primary);
    border-color: var(--color-primary);
    color: white;
}
.pi-form {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    padding: 28px 32px;
}
.pi-field {
    display: flex;
    flex-direction: column;
    gap: 6px;
}
.pi-field label {
    font-size: 13px;
    font-weight: 600;
    color: var(--color-text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.04em;
}
.pi-field input,
.pi-field select {
    padding: 10px 14px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-size: 15px;
    font-family: var(--font-mono);
    color: var(--color-text);
    background: var(--color-bg);
    outline: none;
    transition: border-color 0.15s, box-shadow 0.15s;
}
.pi-field input:focus,
.pi-field select:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(8, 126, 164, 0.12);
}
.pi-actions {
    padding: 0 32px 24px;
}
.pi-generate-btn {
    width: 100%;
    justify-content: center;
    padding: 14px 28px;
    font-size: 16px;
}
.pi-summary {
    background: var(--color-bg-secondary);
    border-top: 1px solid var(--color-border);
    padding: 12px 32px;
}
.pi-summary p {
    margin: 0;
    font-size: 13px;
    font-family: var(--font-mono);
    color: var(--color-text-secondary);
    text-align: center;
}
@media (max-width: 768px) {
    .pi-form {
        grid-template-columns: 1fr;
        padding: 20px;
    }
    .pi-header { padding: 20px; }
    .pi-actions { padding: 0 20px 20px; }
    .pi-summary { padding: 12px 20px; }
}

/* ===== Homepage ===== */
.hero {
    text-align: center;
    padding: 60px 0 40px;
}
.hero h1 {
    font-size: 56px;
    font-weight: 800;
    background: linear-gradient(135deg, var(--color-primary), #6b3fa0);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 16px;
}
.hero .tagline {
    font-size: 22px;
    color: var(--color-text-secondary);
    max-width: 560px;
    margin: 0 auto 32px;
    line-height: 1.5;
}
.hero-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}
.btn {
    display: inline-flex;
    align-items: center;
    padding: 12px 28px;
    border-radius: var(--radius-lg);
    font-size: 16px;
    font-weight: 600;
    font-family: var(--font-sans);
    cursor: pointer;
    border: none;
    text-decoration: none;
    transition: background 0.15s, transform 0.1s;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn-primary {
    background: var(--color-primary);
    color: white;
}
.btn-primary:hover { background: var(--color-primary-dark); color: white; }
.btn-secondary {
    background: var(--color-bg-wash);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}
.btn-secondary:hover { background: var(--color-border); }

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
    margin: 48px 0;
}
.feature-card {
    padding: 28px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    background: var(--color-bg);
    transition: box-shadow 0.2s;
}
.feature-card:hover { box-shadow: var(--shadow-md); }
.feature-card h3 {
    margin: 0 0 8px;
    font-size: 18px;
    font-weight: 700;
    color: var(--color-primary);
}
.feature-card p {
    margin: 0;
    color: var(--color-text-secondary);
    font-size: 15px;
    line-height: 1.6;
}

/* ===== Tables (Reference pages) ===== */
.api-table {
    width: 100%;
    border-collapse: collapse;
    margin: 0 0 24px;
    font-size: 14px;
}
.api-table th, .api-table td {
    padding: 10px 14px;
    text-align: left;
    border-bottom: 1px solid var(--color-border);
}
.api-table th {
    background: var(--color-bg-secondary);
    font-weight: 600;
    font-size: 13px;
    color: var(--color-text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}
.api-table td code {
    font-size: 13px;
}
.api-table tr:hover td {
    background: var(--color-bg-secondary);
}

/* ===== Footer ===== */
.footer {
    margin-left: var(--sidebar-width);
    padding: 32px var(--content-padding);
    border-top: 1px solid var(--color-border);
    color: var(--color-text-secondary);
    font-size: 14px;
    text-align: center;
}

/* ===== Homepage: no sidebar ===== */
.content-full {
    margin-left: 0;
    max-width: 960px;
    margin: 0 auto;
    padding: var(--content-padding);
}
.footer-full {
    margin-left: 0;
}

/* ===== Sponsor Banner (Homepage) ===== */
.sponsor-banner {
    max-width: 680px;
    margin: 0 auto 40px;
    padding: 24px 32px;
    background: linear-gradient(135deg, #1a1a2e, #16213e);
    border: 1px solid #2a2a4a;
    border-radius: var(--radius-lg);
    text-align: center;
}
.sponsor-banner p {
    margin: 0 0 16px;
    color: rgba(255, 255, 255, 0.9);
    font-size: 16px;
    line-height: 1.5;
}
.sponsor-btn {
    font-size: 15px;
    padding: 10px 24px;
}

/* ===== External Sidebar Links ===== */
.sidebar-link-external::after {
    content: " \2197";
    font-size: 11px;
    opacity: 0.5;
}

/* ===== Credits Page ===== */
.credits-card {
    padding: 24px 28px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    background: var(--color-bg);
    margin: 16px 0 0;
}
.credits-card h3 {
    margin: 0 0 4px;
    font-size: 18px;
    font-weight: 700;
    color: var(--color-primary);
}
.credits-card p {
    margin: 0 0 16px;
    color: var(--color-text-secondary);
}
.credits-links {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}
.credits-link {
    font-size: 14px;
    padding: 8px 18px;
}
.credits-sponsor {
    padding: 28px;
    border: 2px solid var(--color-primary);
    border-radius: var(--radius-lg);
    background: var(--color-bg);
    text-align: center;
    margin-top: 16px;
}
.credits-sponsor p {
    margin: 0 0 16px;
    font-size: 16px;
    color: var(--color-text);
}
.credits-sponsor-btn {
    font-size: 16px;
    padding: 12px 28px;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
    .hamburger { display: block; }
    .header-nav { display: none; }
    .sidebar {
        transform: translateX(-100%);
        transition: transform 0.3s ease;
    }
    .sidebar.open {
        transform: translateX(0);
        box-shadow: var(--shadow-md);
    }
    .content, .footer {
        margin-left: 0;
    }
    .content { padding: 24px 16px; }
    .hero h1 { font-size: 36px; }
    .hero .tagline { font-size: 18px; }
    .feature-grid { grid-template-columns: 1fr; }
}
@media (min-width: 769px) and (max-width: 1024px) {
    .sidebar { width: 220px; }
    .content { margin-left: 220px; }
    .footer { margin-left: 220px; }
}