:root {
    /* Brand Colors */
    --wk-blue: #007AC3;
    --wk-blue-medium: #409BD2;
    --wk-blue-light: #A6D0EA;
    --wk-green: #5A8A15;
    --wk-green-vibrant: #6BA31E;
    --wk-green-brand: #85BC20;
    --wk-red: #E5202E;
    --wk-orange: #F97316;
    --wk-orange-wk: #FF6B35;
    --wk-teal: #00A3A1;
    
    /* Modern Neutrals */
    --gray-50: #F9FAFB;
    --gray-100: #F3F4F6;
    --gray-200: #E5E7EB;
    --gray-300: #D1D5DB;
    --gray-400: #9CA3AF;
    --gray-500: #6B7280;
    --gray-600: #4B5563;
    --gray-700: #374151;
    --gray-800: #1F2937;
    --gray-900: #111827;
    
    /* Traditional Neutrals */
    --black: #000000;
    --dark-gray: #191919;
    --logo-gray: #474747;
    --medium-gray: #939393;
    --light-gray: #DADADA;
    --ultra-light-gray: #EDEDED;
    --white: #FFFFFF;
    
    /* Control Surfaces */
    --control-surface: #E8EDF2;
    --slate-pane: #718096;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

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

body {
    font-family: 'Source Sans Pro', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: linear-gradient(135deg, #F8FAFB 0%, #E8EDF2 100%);
    overflow: hidden;
    height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Site Header — dark Developer Portal bar */
.site-header {
    height: 56px;
    z-index: 2000;
    flex-shrink: 0;
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 24px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.15);
}

.header-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    color: white;
    text-decoration: none;
    font-weight: 600;
    font-size: 14px;
}

.header-logo:hover { text-decoration: none; }

.logo-img {
    height: 28px;
    width: auto;
}

.primary-nav {
    display: flex;
    align-items: center;
    gap: 4px;
}

.primary-nav a {
    color: rgba(255,255,255,0.8);
    padding: 8px 14px;
    border-radius: 6px;
    font-size: 13px;
    font-weight: 500;
    transition: all 0.2s;
    text-decoration: none;
}

.primary-nav a:hover { color: white; background: rgba(255,255,255,0.1); text-decoration: none; }
.primary-nav a.active { color: white; background: rgba(255,255,255,0.15); }

.nav-divider {
    width: 1px;
    height: 20px;
    background: rgba(255,255,255,0.2);
    margin: 0 6px;
}

.help-link {
    color: rgba(255,255,255,0.7);
    padding: 6px 12px;
    border-radius: 6px;
    font-size: 13px;
    font-weight: 500;
    transition: all 0.2s;
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 4px;
}

.help-link:hover { color: white; background: rgba(255,255,255,0.1); text-decoration: none; }
.help-link svg { width: 15px; height: 15px; fill: currentColor; }

/* Frame Container */
.frame-container {
    display: flex;
    flex: 1;
    overflow: hidden;
}

/* Navigation Frame */
.nav-frame {
    width: 320px;
    height: 100%;
    border-right: 3px solid transparent;
    border-image: linear-gradient(180deg, var(--wk-blue-light) 0%, var(--wk-teal) 100%) 1;
    overflow-y: auto;
    background: linear-gradient(180deg, #FFFFFF 0%, #F8FAFB 100%);
    box-shadow: 4px 0 12px rgba(0, 122, 195, 0.08);
    flex-shrink: 0;
}

.nav-content {
    padding: 24px 16px;
}

/* Back to APIs link */
.back-to-apis {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 13px;
    font-weight: 600;
    color: var(--wk-blue);
    text-decoration: none;
    padding: 10px 12px;
    margin-bottom: 12px;
    border-bottom: 1px solid var(--gray-200);
    transition: all 0.2s;
}

.back-to-apis svg {
    fill: var(--wk-blue);
    transition: transform 0.2s;
}

.back-to-apis:hover {
    color: var(--wk-teal);
    text-decoration: none;
}

.back-to-apis:hover svg {
    fill: var(--wk-teal);
    transform: translateX(-3px);
}

.nav-frame ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.nav-section {
    margin-bottom: 20px;
}

.nav-section-title {
    font-size: 11px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--medium-gray);
    padding: 8px 10px 4px;
    margin-top: 12px;
}

.nav-frame .nav-level-1 {
    margin-bottom: 3px;
}

.nav-frame .nav-level-1 > a {
    font-weight: 500;
    font-size: 13px;
    color: var(--gray-800);
    padding: 10px 12px;
    display: block;
    text-decoration: none;
    border-radius: 7px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border-left: 3px solid transparent;
    position: relative;
}

.nav-frame .nav-level-1 > a::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: 3px;
    background: linear-gradient(180deg, var(--wk-blue) 0%, var(--wk-teal) 100%);
    border-radius: 0 3px 3px 0;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.nav-frame .nav-level-1 > a:hover {
    background: linear-gradient(90deg, var(--wk-blue-light) 0%, rgba(0, 163, 161, 0.08) 100%);
    color: var(--wk-blue);
    padding-left: 16px;
    box-shadow: 0 2px 6px rgba(0, 122, 195, 0.1);
}

.nav-frame .nav-level-1 > a:hover::before {
    opacity: 1;
}

.nav-frame .nav-level-1 > a.active {
    background: linear-gradient(135deg, var(--wk-blue) 0%, var(--wk-teal) 100%);
    color: var(--white);
    font-weight: 700;
    padding-left: 16px;
    box-shadow: 0 3px 8px rgba(0, 122, 195, 0.25);
    border-left-color: transparent;
}

.nav-frame .nav-level-1 > a.active::before {
    opacity: 0;
}

/* Content Frame */
.content-frame-container {
    flex: 1;
    height: 100%;
    overflow: hidden;
    background: transparent;
}

.content-frame {
    width: 100%;
    height: 100%;
    border: none;
    background-color: var(--white);
}

/* Welcome Screen */
.welcome-screen {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    padding: 40px;
    text-align: center;
    background: linear-gradient(135deg, var(--gray-50) 0%, var(--white) 100%);
}

.welcome-screen .logo {
    width: 120px;
    height: 120px;
    background: linear-gradient(135deg, var(--wk-blue) 0%, var(--wk-blue-medium) 100%);
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 32px;
    box-shadow: var(--shadow-lg);
}

.welcome-screen .logo svg {
    width: 70px;
    height: 70px;
    fill: var(--white);
}

.welcome-screen h2 {
    font-size: 36px;
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: 12px;
}

.welcome-screen .welcome-subtitle {
    font-size: 18px;
    color: var(--gray-600);
    margin-bottom: 32px;
}

.welcome-screen .description {
    max-width: 600px;
    font-size: 14px;
    line-height: 1.6;
    color: var(--gray-700);
    margin-bottom: 32px;
}

.welcome-screen .cta {
    display: inline-block;
    padding: 14px 32px;
    background: linear-gradient(135deg, var(--wk-blue) 0%, var(--wk-teal) 100%);
    color: var(--white);
    text-decoration: none;
    border-radius: 8px;
    font-weight: 600;
    font-size: 15px;
    transition: all 0.3s ease;
    box-shadow: 0 4px 8px rgba(0, 122, 195, 0.2);
    position: relative;
    overflow: hidden;
}

.welcome-screen .cta::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
    transition: left 0.5s ease;
}

.welcome-screen .cta:hover::before {
    left: 100%;
}

.welcome-screen .cta:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(0, 122, 195, 0.3);
    background: linear-gradient(135deg, var(--wk-blue-medium) 0%, var(--wk-teal) 100%);
}

/* Welcome Section Cards */
.welcome-sections {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    max-width: 820px;
    margin-bottom: 32px;
}

.welcome-card {
    background: var(--white);
    border: 1px solid var(--gray-200);
    border-radius: 10px;
    padding: 24px 20px;
    text-align: left;
    transition: all 0.25s ease;
    box-shadow: var(--shadow-sm);
    cursor: pointer;
}

.welcome-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
    border-color: var(--wk-blue-light);
}

.welcome-card-icon {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--wk-blue) 0%, var(--wk-teal) 100%);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 12px;
}

.welcome-card-icon svg {
    width: 22px;
    height: 22px;
    fill: var(--white);
}

.welcome-card h3 {
    font-size: 15px;
    font-weight: 700;
    color: var(--gray-900);
    margin-bottom: 6px;
}

.welcome-card p {
    font-size: 13px;
    line-height: 1.5;
    color: var(--gray-600);
    margin: 0;
}

/* Scrollbar Styling */
.nav-frame::-webkit-scrollbar {
    width: 10px;
}

.nav-frame::-webkit-scrollbar-track {
    background: linear-gradient(180deg, var(--gray-100) 0%, var(--wk-blue-light) 100%);
    border-radius: 5px;
}

.nav-frame::-webkit-scrollbar-thumb {
    background: linear-gradient(180deg, var(--wk-blue) 0%, var(--wk-teal) 100%);
    border-radius: 5px;
    border: 2px solid var(--gray-100);
}

.nav-frame::-webkit-scrollbar-thumb:hover {
    background: linear-gradient(180deg, var(--wk-blue-medium) 0%, var(--wk-teal) 100%);
}

/* Responsive Design */
@media (max-width: 768px) {
    .frame-container {
        flex-direction: column;
    }
    
    .nav-frame {
        width: 100%;
        height: 40vh;
        border-right: none;
        border-bottom: 2px solid var(--wk-blue);
    }
    
    .content-frame-container {
        height: 60vh;
    }
}