/* ========================================
   OpenSignal Digital - Premium Landing Page
   ======================================== */

/* CSS Custom Properties */
:root {
    /* Colors - Modern dark mode with vibrant accents */
    --color-bg-dark: #0a0f1a;
    --color-bg-card: #111827;
    --color-bg-card-hover: #1a2235;
    --color-bg-light: #f8fafc;
    --color-bg-white: #ffffff;

    --color-primary: #3b82f6;
    --color-primary-dark: #2563eb;
    --color-primary-glow: rgba(59, 130, 246, 0.3);
    --color-accent: #06b6d4;
    --color-gradient-start: #3b82f6;
    --color-gradient-end: #06b6d4;

    --color-text-white: #ffffff;
    --color-text-light: #e2e8f0;
    --color-text-muted: #94a3b8;
    --color-text-dark: #1e293b;
    --color-text-body: #475569;

    --color-border-dark: rgba(255, 255, 255, 0.1);
    --color-border-light: #e2e8f0;

    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    --font-size-4xl: 2.5rem;
    --font-size-5xl: 3rem;
    --font-size-6xl: 3.5rem;

    --line-height-tight: 1.2;
    --line-height-base: 1.6;

    /* 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;
    --spacing-4xl: 6rem;
    --spacing-5xl: 8rem;

    /* Container */
    --container-max-width: 1200px;
    --container-padding: 1.5rem;

    /* Effects */
    --border-radius-sm: 8px;
    --border-radius-md: 12px;
    --border-radius-lg: 16px;
    --border-radius-xl: 24px;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    --shadow-glow: 0 0 40px var(--color-primary-glow);

    --transition-fast: 0.15s ease;
    --transition-base: 0.2s ease;
    --transition-slow: 0.3s ease;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: var(--line-height-base);
    color: var(--color-text-dark);
    background-color: var(--color-bg-white);
}

/* Container */
.container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--container-padding);
}

/* Typography */
h1,
h2,
h3,
h4 {
    line-height: var(--line-height-tight);
    font-weight: 700;
}

h1 {
    font-size: var(--font-size-4xl);
}

h2 {
    font-size: var(--font-size-3xl);
    margin-bottom: var(--spacing-lg);
}

h3 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-sm);
}

p {
    margin-bottom: var(--spacing-md);
}

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

/* Gradient Text */
.gradient-text {
    background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Section Label */
.section-label {
    display: inline-block;
    font-size: var(--font-size-sm);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
}

.section-intro {
    font-size: var(--font-size-lg);
    color: var(--color-text-body);
    max-width: 600px;
    margin-bottom: var(--spacing-2xl);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    font-weight: 600;
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: var(--border-radius-md);
    border: none;
    cursor: pointer;
    transition: all var(--transition-base);
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-gradient-start), var(--color-gradient-end));
    color: var(--color-text-white);
    box-shadow: var(--shadow-md), var(--shadow-glow);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg), 0 0 60px var(--color-primary-glow);
    color: var(--color-text-white);
}

.btn-secondary {
    background: transparent;
    color: var(--color-text-light);
    border: 1px solid var(--color-border-dark);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.1);
    color: var(--color-text-white);
}

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

.btn-xl {
    padding: var(--spacing-lg) var(--spacing-2xl);
    font-size: var(--font-size-lg);
    border-radius: var(--border-radius-lg);
}

.btn-icon {
    font-size: var(--font-size-sm);
}

/* ========================================
   Header
   ======================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: var(--spacing-lg) 0;
    background: rgba(10, 15, 26, 0.8);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--color-border-dark);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    height: 56px;
    width: auto;
    transform: translateY(2px);
}

.header-cta {
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--color-text-light);
    padding: var(--spacing-sm) var(--spacing-lg);
    border: 1px solid var(--color-border-dark);
    border-radius: var(--border-radius-md);
    transition: all var(--transition-base);
}

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

/* ========================================
   Hero Section
   ======================================== */
.hero {
    position: relative;
    padding: calc(var(--spacing-5xl) + 80px) 0 var(--spacing-5xl);
    background: var(--color-bg-dark);
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse 80% 50% at 50% -20%, rgba(59, 130, 246, 0.15), transparent),
        radial-gradient(ellipse 60% 40% at 80% 60%, rgba(6, 182, 212, 0.1), transparent);
}

.hero-content {
    position: relative;
    max-width: 800px;
}

.hero-badge {
    display: inline-block;
    font-size: var(--font-size-sm);
    font-weight: 500;
    color: var(--color-accent);
    padding: var(--spacing-xs) var(--spacing-md);
    background: rgba(6, 182, 212, 0.1);
    border: 1px solid rgba(6, 182, 212, 0.3);
    border-radius: 100px;
    margin-bottom: var(--spacing-xl);
}

.hero h1 {
    color: var(--color-text-white);
    margin-bottom: var(--spacing-xl);
}

.hero-sub {
    font-size: var(--font-size-xl);
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-2xl);
    max-width: 640px;
}

.hero-cta-group {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

/* ========================================
   Problems Section
   ======================================== */
.problems {
    padding: var(--spacing-5xl) 0;
    background: var(--color-bg-light);
}

.problems h2 {
    color: var(--color-text-dark);
}

.problems-grid {
    display: grid;
    gap: var(--spacing-xl);
}

.problem-card {
    background: var(--color-bg-white);
    padding: var(--spacing-2xl);
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--color-border-light);
    transition: all var(--transition-base);
}

.problem-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.problem-icon-wrap {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.1), rgba(6, 182, 212, 0.1));
    border-radius: var(--border-radius-md);
    margin-bottom: var(--spacing-lg);
}

.problem-icon {
    font-size: var(--font-size-xl);
}

.problem-card h3 {
    color: var(--color-text-dark);
}

.problem-card p {
    color: var(--color-text-body);
    margin-bottom: 0;
}

/* ========================================
   Example Section
   ======================================== */
.example {
    padding: var(--spacing-5xl) 0;
    background: var(--color-bg-dark);
}

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

.example h2 {
    color: var(--color-text-white);
}

.example p {
    color: var(--color-text-muted);
}

.example-features {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-2xl);
}

.feature-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--color-text-light);
}

.feature-check {
    color: var(--color-accent);
    font-weight: 600;
}

.example-note {
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
    font-style: italic;
    margin-top: var(--spacing-xl);
    margin-bottom: 0;
}

/* ========================================
   How We Work Section
   ======================================== */
.how-we-work {
    padding: var(--spacing-5xl) 0;
    background: var(--color-bg-white);
}

.how-we-work h2 {
    color: var(--color-text-dark);
}

.approach-grid {
    display: grid;
    gap: var(--spacing-xl);
}

.approach-card {
    position: relative;
    padding: var(--spacing-2xl);
    background: var(--color-bg-light);
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--color-border-light);
    transition: all var(--transition-base);
}

.approach-card:hover {
    border-color: var(--color-primary);
}

.approach-number {
    font-size: var(--font-size-sm);
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
}

.approach-card h3 {
    color: var(--color-text-dark);
}

.approach-card p {
    color: var(--color-text-body);
    margin-bottom: 0;
}

/* ========================================
   Founder Section
   ======================================== */
.founder {
    padding: var(--spacing-4xl) 0;
    background: var(--color-bg-light);
}

.founder-card {
    max-width: 700px;
    margin: 0 auto;
    text-align: center;
}

.founder-text {
    font-size: var(--font-size-lg);
    color: var(--color-text-body);
    margin-bottom: 0;
}

.founder-text strong {
    color: var(--color-text-dark);
}

/* ========================================
   Contact Section
   ======================================== */
.contact {
    padding: var(--spacing-5xl) 0;
    background: var(--color-bg-dark);
    text-align: center;
}

.contact-content {
    max-width: 600px;
    margin: 0 auto;
}

.contact h2 {
    color: var(--color-text-white);
}

.contact p {
    font-size: var(--font-size-lg);
    color: var(--color-text-muted);
    margin-bottom: var(--spacing-2xl);
}

/* ========================================
   Footer
   ======================================== */
.footer {
    padding: var(--spacing-2xl) 0;
    background: var(--color-bg-dark);
    border-top: 1px solid var(--color-border-dark);
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-lg);
}

.footer-logo {
    height: 32px;
    width: auto;
    opacity: 0.7;
}

.footer p {
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
    margin-bottom: 0;
}

/* ========================================
   Responsive - Tablet and Up
   ======================================== */
@media (min-width: 640px) {
    :root {
        --container-padding: 2rem;
    }

    h1 {
        font-size: var(--font-size-5xl);
    }

    h2 {
        font-size: var(--font-size-4xl);
    }

    .logo {
        height: 64px;
    }

    .problems-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .approach-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* ========================================
   Responsive - Desktop
   ======================================== */
@media (min-width: 1024px) {
    h1 {
        font-size: var(--font-size-6xl);
    }

    .problems-grid {
        grid-template-columns: repeat(4, 1fr);
    }

    .approach-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

/* ========================================
   Accessibility
   ======================================== */
@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    *,
    *::before,
    *::after {
        transition-duration: 0.01ms !important;
        animation-duration: 0.01ms !important;
    }
}

/* Focus styles for keyboard navigation */
a:focus-visible,
button:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}