/* LightLink AI - Main Stylesheet */

/* CSS Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: #AAB2C8;
    background-color: #0A0E17;
    padding-top: 80px; /* Space for fixed navbar */
    overflow-x: hidden; /* guard against accidental overflow */
}

/* CSS Custom Properties (Design System) */
:root {
    /* Colors */
    --color-primary-start: #1DA1F2;
    --color-primary-end: #0CE6F2;
    --color-accent-violet: #5956FF;
    --color-background-dark: #0A0E17;
    --color-surface-gray: #1B1F27;
    --color-text-white: #FFFFFF;
    --color-text-muted: #AAB2C8;

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #1DA1F2 0%, #0CE6F2 50%, #5956FF 100%);
    --gradient-glow: radial-gradient(circle at 50% 50%, rgba(29,161,242,0.25), rgba(0,0,0,0) 70%);
    --gradient-bg: linear-gradient(135deg, #0A0E17 0%, #0F1419 50%, #0A0E17 100%);

    /* Typography */
    --font-heading: 'Manrope', sans-serif;
    --font-body: 'Inter', sans-serif;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 0.75rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;

    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 16px;
    --radius-lg: 24px;
    --radius-xl: 32px;

    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 16px rgba(0,0,0,0.2);
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.3);
    --shadow-glow: 0px 0px 20px rgba(29,161,242,0.25);

    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;

    /* Layout */
    --container-max-width: 1440px;
    --grid-gutter: 2rem;
    --section-padding: 100px 0;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 600;
    color: var(--color-text-white);
    line-height: 1.2;
}

h1 {
    font-size: 3.5rem;
    font-weight: 800;
    line-height: 1.1;
}

h2 {
    font-size: 3rem;
    font-weight: 700;
    line-height: 1.15;
}

h3 {
    font-size: 2rem;
    font-weight: 700;
    line-height: 1.2;
}

p {
    font-size: 1.125rem;
    line-height: 1.5;
    color: var(--color-text-muted);
}

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

a:hover {
    color: var(--color-primary-end);
}

/* Layout Utilities */
.container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.section {
    padding: var(--section-padding);
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-3xl);
}

.section-title {
    margin-bottom: var(--spacing-md);
}

.section-subtitle {
    font-size: 1.25rem;
    max-width: 600px;
    margin: 0 auto;
}

/* Grid System */
.grid {
    display: grid;
    gap: var(--grid-gutter);
}

.grid-2 {
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-4 {
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

/* Button Styles */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 1rem;
    text-decoration: none;
    transition: all var(--transition-fast);
    cursor: pointer;
    border: none;
    min-height: 48px;
}

.btn-primary {
    background: var(--gradient-primary);
    color: var(--color-text-white);
    box-shadow: var(--shadow-glow);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(29,161,242,0.4);
    filter: brightness(1.1);
    color: var(--color-text-white);
}

.btn-secondary {
    background: transparent;
    color: var(--color-primary-start);
    border: 1px solid var(--color-primary-start);
}

.btn-secondary:hover {
    background: var(--color-primary-start);
    color: var(--color-text-white);
}

.btn-large {
    padding: var(--spacing-lg) var(--spacing-2xl);
    font-size: 1.125rem;
}

/* Form Styles */
.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-group label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
    color: var(--color-text-white);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: var(--spacing-md);
    background: var(--color-surface-gray);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: var(--radius-md);
    color: var(--color-text-white);
    font-size: 1rem;
    transition: border-color var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-primary-start);
    box-shadow: 0 0 0 3px rgba(29,161,242,0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

/* Utility Classes */
.text-center {
    text-align: center;
}

.text-gradient {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.glow {
    position: relative;
}

.glow::before {
    content: '';
    position: absolute;
    inset: -2px;
    border-radius: inherit;
    background: var(--gradient-primary);
    opacity: 0;
    transition: opacity var(--transition-normal);
    z-index: -1;
}

.glow:hover::before {
    opacity: 0.3;
}

/* Animation Classes */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

@keyframes float {
    0%, 100% {
        transform: translateY(0px);
    }
    50% {
        transform: translateY(-10px);
    }
}

.fade-in-up {
    animation: fadeInUp 0.6s ease-out forwards;
}

.animate-pulse {
    animation: pulse 2s infinite;
}

.animate-float {
    animation: float 3s ease-in-out infinite;
}

/* Responsive Design */
@media (max-width: 768px) {
    :root {
        --section-padding: 64px 0;
        --spacing-3xl: 2rem;
    }

    h1 {
        font-size: 2.5rem;
    }

    h2 {
        font-size: 2rem;
    }

    h3 {
        font-size: 1.5rem;
    }

    p {
        font-size: 1rem;
    }

    .container {
        padding: 0 var(--spacing-md);
    }

    .btn {
        width: 100%;
        justify-content: center;
    }

    .grid-2,
    .grid-3,
    .grid-4 {
        grid-template-columns: 1fr;
    }
}