/* ============================================
   CITIUS AI - Design System & Styles
   ============================================ */

/* CSS Custom Properties */
:root {
    /* Colors */
    --color-background: #F5F3EE;
    --color-background-light: #FAF9F7;
    --color-primary: #1a4d2e;
    --color-primary-light: #2d6a4f;
    --color-primary-dark: #0f2d1a;
    --color-text: #1a1a1a;
    --color-text-muted: #6b6b6b;
    --color-border: #e0ddd5;
    --color-white: #ffffff;

    /* Typography */
    --font-serif: 'Playfair Display', Georgia, serif;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;

    /* Spacing */
    --sidebar-width: 200px;
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 5rem;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 400ms ease;

    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-full: 50%;
}

/* ============================================
   Reset & Base Styles
   ============================================ */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-sans);
    background-color: var(--color-background);
    color: var(--color-text);
    line-height: 1.6;
    min-height: 100vh;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color var(--transition-fast);
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

/* ============================================
   Left Sidebar Navigation
   ============================================ */
.sidebar {
    position: fixed;
    left: 0;
    top: 0;
    width: var(--sidebar-width);
    height: 100vh;
    padding: var(--spacing-xl) var(--spacing-lg);
    z-index: 100;
    display: flex;
    flex-direction: column;
}

.sidebar-content {
    display: flex;
    flex-direction: column;
    height: 100%;
}

/* Logo */
.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xl);
}

.logo-circles {
    display: flex;
    align-items: center;
    gap: 4px;
}

.circle {
    width: 14px;
    height: 14px;
    border-radius: var(--radius-full);
}

.circle-outline {
    border: 2px solid var(--color-primary);
}

.circle-filled {
    background-color: var(--color-primary);
}

.logo-text {
    font-family: var(--font-sans);
    font-weight: 600;
    font-size: 1.1rem;
    color: var(--color-primary);
}

.logo-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-primary);
}

/* Navigation Links */
.nav-links {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.nav-link {
    font-size: 0.95rem;
    color: var(--color-text);
    padding: var(--spacing-xs) 0;
    position: relative;
    width: fit-content;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 4px;
    left: 0;
    width: 0;
    height: 1px;
    background-color: var(--color-primary);
    transition: width var(--transition-normal);
}

.nav-link:hover::after {
    width: 100%;
}

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

/* External link arrow - hidden by default, visible on hover */
.nav-arrow {
    display: inline-block;
    opacity: 0;
    transform: translateX(-4px);
    transition: all var(--transition-fast);
}

.nav-link-external:hover .nav-arrow {
    opacity: 1;
    transform: translateX(0);
}

/* Fade other links when hovering any nav link */
.nav-links:hover .nav-link:not(:hover) {
    opacity: 0.3;
}

.nav-link {
    transition: color var(--transition-fast), opacity var(--transition-fast);
}

/* ============================================
   Main Content Area
   ============================================ */
.main-content {
    margin-left: var(--sidebar-width);
    min-height: 100vh;
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
    padding: var(--spacing-2xl) var(--spacing-xl);
    padding-top: 15vh;
    max-width: 900px;
}

.hero-content {
    max-width: 700px;
}

.hero-tagline {
    font-size: 0.95rem;
    color: var(--color-primary);
    font-weight: 500;
    letter-spacing: 0.02em;
    margin-bottom: var(--spacing-md);
    animation: fadeInUp 0.6s ease forwards;
}

.hero-title {
    font-family: var(--font-serif);
    font-size: clamp(3rem, 8vw, 5rem);
    font-weight: 400;
    line-height: 1.1;
    letter-spacing: -0.02em;
    color: var(--color-text);
    margin-bottom: var(--spacing-lg);
}

.hero-subtitle {
    font-size: 1.1rem;
    color: var(--color-text-muted);
    max-width: 450px;
    margin-bottom: var(--spacing-xl);
    line-height: 1.7;
}

/* CTA Button */
.cta-button {
    display: inline-block;
    background-color: var(--color-primary);
    color: var(--color-white);
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    font-weight: 500;
    transition: all var(--transition-normal);
    border: none;
    cursor: pointer;
}

.cta-button:hover {
    background-color: var(--color-primary-light);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(26, 77, 46, 0.25);
}

/* ============================================
   Hero Image Section
   ============================================ */
.hero-image-section {
    padding: 0 var(--spacing-xl);
    padding-right: var(--spacing-xl);
}

.hero-image-container {
    position: relative;
    width: 100%;
    max-width: 1000px;
    border-radius: var(--radius-lg);
    overflow: hidden;
    background-color: var(--color-border);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
}

.hero-image {
    width: 100%;
    height: auto;
    display: block;
    object-fit: contain;
}

.hero-image-placeholder {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
}

.placeholder-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--color-white);
    opacity: 0.9;
}

.placeholder-content span {
    font-size: 1.1rem;
    font-weight: 500;
}

/* ============================================
   Features Section
   ============================================ */
.features {
    padding: var(--spacing-2xl) var(--spacing-xl);
    margin-top: var(--spacing-2xl);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-xl);
    max-width: 1000px;
}

.feature-card {
    padding: var(--spacing-lg);
    background-color: var(--color-background-light);
    border-radius: var(--radius-lg);
    transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
}

.feature-icon {
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
}

.feature-title {
    font-family: var(--font-serif);
    font-size: 1.3rem;
    font-weight: 500;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.feature-description {
    font-size: 0.95rem;
    color: var(--color-text-muted);
    line-height: 1.7;
}

/* ============================================
   Footer
   ============================================ */
.footer {
    position: relative;
    background-color: var(--color-background);
    padding: var(--spacing-xl) var(--spacing-xl);
    margin-top: var(--spacing-2xl);
}

.footer-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    max-width: 1200px;
    margin: 0 auto;
    padding-left: var(--sidebar-width);
}

/* Footer Left - Email Form */
.footer-left {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

.footer-label {
    font-size: 0.9rem;
    color: var(--color-text);
}

.footer-label-underline {
    text-decoration: underline;
    text-underline-offset: 2px;
}

.email-form {
    display: flex;
}

.email-input-wrapper {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    background-color: #E8E4DD;
    border-radius: 50px;
    padding: 0.6rem 1rem;
}

.email-icon {
    color: var(--color-text);
    flex-shrink: 0;
    width: 20px;
    height: 20px;
}

.email-input {
    border: none;
    background: none;
    font-family: var(--font-sans);
    font-size: 0.9rem;
    color: var(--color-text);
    width: 200px;
    outline: none;
}

.email-input::placeholder {
    color: var(--color-text-muted);
}

.email-submit {
    display: flex;
    align-items: center;
    justify-content: center;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.4rem;
    border-radius: 50%;
    color: var(--color-text);
    transition: all var(--transition-fast);
    opacity: 0;
    pointer-events: none;
}

.email-submit.visible {
    opacity: 1;
    pointer-events: auto;
}

.email-submit:hover {
    background-color: rgba(0, 0, 0, 0.08);
}

/* Footer CTA Link */
.footer-cta {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    background-color: transparent;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    color: var(--color-text);
    font-size: 0.9rem;
    transition: all var(--transition-fast);
}

.footer-cta:hover {
    background-color: var(--color-primary);
    border-color: var(--color-primary);
    color: white;
}

/* Footer Center - Social Links */
.footer-center {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

.footer-link {
    font-size: 0.9rem;
    color: var(--color-text);
    transition: color var(--transition-fast);
}

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

.footer-link-underline {
    text-decoration: underline;
    text-underline-offset: 3px;
}

/* Footer Right - Legal Links */
.footer-right {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 1024px) {
    .footer-content {
        flex-wrap: wrap;
        gap: var(--spacing-md);
        justify-content: center;
    }

    .footer-left,
    .footer-center,
    .footer-right {
        justify-content: center;
    }
}

@media (max-width: 768px) {
    :root {
        --sidebar-width: 0px;
    }

    .sidebar {
        display: none;
    }

    .main-content {
        margin-left: 0;
    }

    .hero {
        padding: var(--spacing-xl) var(--spacing-md);
        padding-top: var(--spacing-xl);
    }

    .hero-title {
        font-size: clamp(2.5rem, 10vw, 4rem);
    }

    .hero-image-section {
        padding: 0 var(--spacing-md);
    }

    .features {
        padding: var(--spacing-xl) var(--spacing-md);
    }

    .footer {
        position: relative;
        margin-top: var(--spacing-xl);
    }

    .footer-content {
        margin-left: 0;
        flex-direction: column;
        gap: var(--spacing-md);
        text-align: center;
    }

    .footer-left {
        flex-direction: column;
    }
}

/* ============================================
   Animations
   ============================================ */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.hero-title,
.hero-subtitle,
.cta-button {
    animation: fadeInUp 0.6s ease forwards;
}

.hero-subtitle {
    animation-delay: 0.1s;
}

.cta-button {
    animation-delay: 0.2s;
}

.feature-card {
    animation: fadeInUp 0.6s ease forwards;
}

.feature-card:nth-child(1) {
    animation-delay: 0.1s;
}

.feature-card:nth-child(2) {
    animation-delay: 0.2s;
}

.feature-card:nth-child(3) {
    animation-delay: 0.3s;
}