/* UI/UX Refactor: Senior Developer Standard */
:root {
    --sidebar-width: 260px;
    --max-content: 1200px;
    --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Dark Theme - True Black Edition */
body.dark {
    --bg: #000000;
    --sidebar-bg: #000000;
    --card-bg: #0a0a0a;
    --text: #ffffff;
    --text-muted: #888888;
    --border: #1a1a1a;
    --primary: #3b82f6;
    --primary-dim: rgba(59, 130, 246, 0.1);
    --code-bg: #050505;
    --code-text: #e2e8f0;
    --hover-bg: #111111;
    --selection: rgba(59, 130, 246, 0.3);
}

/* Light Theme - Eye-Relaxing Edition */
body.light {
    --bg: #fafafa;
    --sidebar-bg: #f5f5f5;
    --card-bg: #ffffff;
    --text: #1a1a1a;
    --text-muted: #666666;
    --border: #e0e0e0;
    --primary: #2563eb;
    --primary-dim: rgba(37, 99, 235, 0.08);
    --code-bg: #f1f5f9;
    --code-text: #0f172a;
    --hover-bg: #efefef;
    --selection: rgba(37, 99, 235, 0.2);
}

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

::selection {
    background-color: var(--selection);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, sans-serif;
    background-color: var(--bg);
    color: var(--text);
    line-height: 1.8;
    -webkit-font-smoothing: antialiased;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Layout */
.app-container {
    display: flex;
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    height: 100vh;
    background-color: var(--sidebar-bg);
    border-right: 1px solid var(--border);
    position: fixed;
    top: 0;
    left: 0;
    overflow-y: auto;
    z-index: 2000;
    padding: 2.5rem 0;
    transition: var(--transition-base);
}

.sidebar-header {
    padding: 0 1.5rem 2rem 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo-text {
    font-weight: 700;
    font-size: 1.15rem;
    letter-spacing: -0.02em;
    text-transform: lowercase;
}

.sidebar-nav ul {
    list-style: none;
}

.sidebar-nav a {
    display: flex;
    align-items: center;
    gap: 0.85rem;
    padding: 0.65rem 1.5rem;
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: var(--transition-fast);
}

.sidebar-nav a i {
    width: 16px;
    height: 16px;
    opacity: 0.7;
}

.sidebar-nav a:hover {
    color: var(--text);
    background-color: var(--hover-bg);
}

.sidebar-nav a.active {
    color: var(--primary);
    background-color: var(--primary-dim);
    border-right: 2px solid var(--primary);
}

/* Submenu */
.sidebar-nav .submenu {
    list-style: none;
    margin-left: 1.5rem;
    padding-top: 0.2rem;
    border-left: 1px solid var(--border);
}

.sidebar-nav .submenu a {
    padding: 0.4rem 1rem;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.sidebar-nav .submenu a:hover {
    color: var(--text);
    background-color: transparent;
}

.sidebar-nav .submenu a.active {
    color: var(--primary);
    border: none;
    background-color: transparent;
    font-weight: 600;
}

/* Main Content */
.content {
    margin-left: var(--sidebar-width);
    padding: 6rem 4rem;
    width: calc(100% - var(--sidebar-width));
    max-width: 100%;
}

.section {
    padding-bottom: 6rem;
    max-width: var(--max-content);
    width: 100%;
}

h1 {
    font-size: 4rem;
    font-weight: 800;
    line-height: 1.05;
    margin-bottom: 2.5rem;
    letter-spacing: -0.05em;
}

h2 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 1.75rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    letter-spacing: -0.02em;
}

h2 i {
    color: var(--primary);
    opacity: 0.8;
}

h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin: 2.5rem 0 1rem 0;
    letter-spacing: -0.01em;
}

h4 {
    font-size: 1.05rem;
    font-weight: 600;
    margin: 2rem 0 0.75rem 0;
}

p {
    margin-bottom: 1.75rem;
    color: var(--text-muted);
    font-size: 1.05rem;
}

p.lead {
    font-size: 1.4rem;
    color: var(--text);
    font-weight: 400;
    margin-bottom: 3rem;
    line-height: 1.6;
}

/* Inline code */
code {
    font-family: 'Fira Code', monospace;
    background-color: var(--code-bg);
    padding: 0.15em 0.4em;
    border-radius: 4px;
    font-size: 0.9em;
    color: var(--primary);
}

/* Badges */
.badges {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-bottom: 3rem;
}

.badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background-color: var(--primary-dim);
    color: var(--primary);
    padding: 0.4rem 0.85rem;
    border-radius: 6px;
    font-size: 0.8rem;
    font-weight: 600;
    border: 1px solid transparent;
    transition: var(--transition-fast);
    cursor: default;
}

.badge:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.badge-accent {
    background-color: rgba(249, 115, 22, 0.1);
    color: #f97316;
}

.badge-green {
    background-color: rgba(16, 185, 129, 0.1);
    color: #10b981;
}

.badge-purple {
    background-color: rgba(139, 92, 246, 0.1);
    color: #8b5cf6;
}

body.dark .badge {
    border-color: #1a1a1a;
}

body.dark .badge-accent {
    border-color: rgba(249, 115, 22, 0.2);
}

body.dark .badge-green {
    border-color: rgba(16, 185, 129, 0.2);
}

body.dark .badge-purple {
    border-color: rgba(139, 92, 246, 0.2);
}

/* Code Blocks */
.code-block {
    position: relative;
    background-color: var(--code-bg);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 2rem;
    margin: 2rem 0;
    transition: var(--transition-base);
}

.code-block:hover {
    border-color: var(--primary);
}

.code-block pre {
    overflow-x: auto;
    overflow-y: hidden;
    -ms-overflow-style: none;
    scrollbar-width: none;
}

.code-block pre::-webkit-scrollbar {
    display: none;
}

.code-block code {
    font-family: 'Fira Code', monospace;
    font-size: 0.95rem;
    color: var(--code-text);
    white-space: pre-wrap;
    word-break: break-all;
    background: none;
    padding: 0;
    border-radius: 0;
}

.code-block[data-lang]::before {
    content: attr(data-lang);
    position: absolute;
    top: 0.75rem;
    right: 1.25rem;
    font-size: 0.65rem;
    text-transform: uppercase;
    color: var(--text-muted);
    font-weight: 700;
    letter-spacing: 0.05em;
    opacity: 0.6;
}

/* Syntax Highlighting overrides for Light Theme */
body.light .code-block code {
    color: #1e293b;
}

/* Copy Button */
.copy-btn {
    position: absolute;
    bottom: 0.75rem;
    right: 0.75rem;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background-color: var(--hover-bg);
    border: 1px solid var(--border);
    color: var(--text-muted);
    padding: 0.45rem 0.8rem;
    border-radius: 6px;
    font-size: 0.75rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-fast);
}

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

/* Theme Toggle Button */
.theme-btn {
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition-fast);
}

.theme-btn:hover {
    color: var(--text);
    background-color: var(--hover-bg);
}

/* Tables */
.table-container {
    overflow-x: auto;
    margin: 3rem 0;
    border: 1px solid var(--border);
    border-radius: 12px;
    background-color: var(--card-bg);
}

table {
    width: 100%;
    border-collapse: collapse;
    text-align: left;
}

th {
    padding: 1.25rem 1.5rem;
    background-color: var(--hover-bg);
    font-weight: 600;
    border-bottom: 1px solid var(--border);
    color: var(--text);
    text-transform: uppercase;
    font-size: 0.75rem;
    letter-spacing: 0.05em;
}

td {
    padding: 1.25rem 1.5rem;
    border-bottom: 1px solid var(--border);
    font-size: 0.95rem;
}

tr:last-child td {
    border-bottom: none;
}

td code {
    font-size: 0.85em;
}

/* Gateway Cards */
.gateway-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.gateway-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 2rem;
    transition: var(--transition-base);
}

.gateway-card:hover {
    border-color: var(--primary);
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
}

.gateway-card h4 {
    font-size: 1.15rem;
    font-weight: 700;
    margin: 0 0 0.5rem 0;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.gateway-card p {
    font-size: 0.9rem;
    margin-bottom: 1rem;
    color: var(--text-muted);
}

.gateway-card .badge {
    font-size: 0.7rem;
    padding: 0.25rem 0.6rem;
}

.gateway-badges {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

/* Tier list */
.tier-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    margin: 2rem 0;
}

.tier-item {
    display: flex;
    align-items: flex-start;
    gap: 1.25rem;
    background-color: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.75rem;
    transition: var(--transition-base);
}

.tier-item:hover {
    border-color: var(--primary);
}

.tier-number {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    min-width: 36px;
    background-color: var(--primary-dim);
    color: var(--primary);
    border-radius: 8px;
    font-weight: 700;
    font-size: 0.9rem;
}

.tier-content h4 {
    margin: 0 0 0.5rem 0;
    font-size: 1.05rem;
}

.tier-content p {
    font-size: 0.9rem;
    margin-bottom: 0;
}

/* Mobile Header */
.mobile-header {
    display: none;
    padding: 1rem 1.5rem;
    background-color: var(--bg);
    border-bottom: 1px solid var(--border);
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 1100;
}

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

.mobile-only {
    display: none;
}

#menu-toggle, #sidebar-close {
    background: none;
    border: none;
    color: var(--text-muted);
}

#menu-toggle:hover, #sidebar-close:hover {
    color: var(--text);
    background-color: var(--hover-bg);
}

.header-actions-sidebar {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

/* Footers */
.main-footer {
    border-top: 1px solid var(--border);
    padding-top: 3rem;
    margin-top: 3rem;
    font-size: 0.9rem;
    color: var(--text-muted);
}

.main-footer a {
    color: var(--primary);
    text-decoration: none;
}

/* Responsive */
@media (max-width: 1024px) {
    .content {
        padding: 4rem 2rem;
    }
}

@media (max-width: 768px) {
    .sidebar {
        width: 100vw;
        height: 100vh;
        max-width: 100vw;
        transform: translateX(-100%);
        padding: 1.5rem 0;
        opacity: 0;
        visibility: hidden;
    }

    .sidebar.active {
        transform: translateX(0);
        opacity: 1;
        visibility: visible;
        background-color: var(--bg);
    }

    .sidebar-header {
        padding: 0 1.5rem 1.5rem 1.5rem;
    }

    .mobile-only {
        display: flex;
    }

    .content {
        margin-left: 0;
        padding: 3rem 1.5rem;
    }

    .mobile-header {
        display: flex;
    }

    h1 {
        font-size: 2.75rem;
    }

    .sidebar-nav a {
        padding: 1rem 1.5rem;
        font-size: 1.1rem;
    }

    .gateway-grid {
        grid-template-columns: 1fr;
    }
}