/**
 * Lernkurven.com - Premium Design System
 * Farben vom Logo: Navy (#003D7A), Sky-Blue (#4A9FD8), Orange (#FF8C00)
 */

:root {
    /* === LOGO-FARBEN === */
    --navy-blue: #003D7A;
    --navy-dark: #002850;
    --sky-blue: #4A9FD8;
    --bright-orange: #FF8C00;
    --orange-light: #FFA500;
    
    /* === ERWEITERTE PALETTE === */
    --success: #00C853;
    --warning: #FFB300;
    --white: #FFFFFF;
    --gray-50: #F8FAFC;
    --gray-100: #F1F5F9;
    --gray-200: #E2E8F0;
    --gray-700: #334155;
    --gray-900: #0F172A;
    
    /* === GRADIENTS === */
    --gradient-primary: linear-gradient(135deg, var(--navy-blue) 0%, var(--sky-blue) 100%);
    --gradient-accent: linear-gradient(135deg, var(--bright-orange) 0%, var(--orange-light) 100%);
    --gradient-hero: linear-gradient(135deg, #001A3D 0%, var(--navy-blue) 50%, var(--sky-blue) 100%);
    
    /* === 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;
    
    /* === SHADOWS === */
    --shadow-sm: 0 1px 2px rgba(0, 61, 122, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 61, 122, 0.07);
    --shadow-lg: 0 10px 15px rgba(0, 61, 122, 0.1);
    --shadow-xl: 0 20px 25px rgba(0, 61, 122, 0.15);
    --shadow-glow: 0 0 40px rgba(255, 140, 0, 0.3);
    
    /* === BORDER RADIUS === */
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 9999px;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--gray-900);
    background: var(--white);
    overflow-x: hidden;
}

/* === TYPOGRAPHY === */
h1, h2, h3, h4 {
    line-height: 1.2;
    font-weight: 800;
    letter-spacing: -0.02em;
}

h1 {
    font-size: clamp(2.5rem, 5vw, 4rem);
    margin-bottom: var(--spacing-lg);
}

h2 {
    font-size: clamp(2rem, 4vw, 3rem);
    margin-bottom: var(--spacing-md);
}

h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
}

p {
    margin-bottom: var(--spacing-md);
    color: var(--gray-700);
    font-size: 1.125rem;
    line-height: 1.7;
}

/* === HEADER - Glassmorphism === */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(0, 61, 122, 0.1);
    transition: all 0.3s ease;
}

.header.scrolled {
    background: rgba(255, 255, 255, 0.95);
    box-shadow: var(--shadow-md);
}

.nav {
    max-width: 1400px;
    margin: 0 auto;
    padding: var(--spacing-md) var(--spacing-xl);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo-container {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    text-decoration: none;
}

.logo-text {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.logo-text-main {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--navy-blue);
    letter-spacing: -0.02em;
}

.logo-text-sub {
    font-size: 0.75rem;
    color: var(--gray-700);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-xl);
    align-items: center;
}

.nav-menu a {
    color: var(--gray-700);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.95rem;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-md);
    transition: all 0.2s;
}

.nav-menu a:hover {
    color: var(--navy-blue);
    background: var(--gray-100);
}

/* === BUTTONS === */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: 0.875rem 2rem;
    font-size: 1rem;
    font-weight: 700;
    text-align: center;
    border-radius: var(--radius-full);
    border: none;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    text-decoration: none;
    font-family: inherit;
    white-space: nowrap;
}

.btn-primary {
    background: var(--gradient-accent);
    color: var(--white);
    box-shadow: 0 4px 14px rgba(255, 140, 0, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(255, 140, 0, 0.5);
}

.btn-secondary {
    background: var(--gradient-primary);
    color: var(--white);
    box-shadow: 0 4px 14px rgba(0, 61, 122, 0.3);
}

.btn-secondary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 61, 122, 0.4);
}

.btn-outline {
    background: transparent;
    color: var(--navy-blue);
    border: 2px solid var(--navy-blue);
    box-shadow: none;
}

.btn-outline:hover {
    background: var(--navy-blue);
    color: var(--white);
    transform: translateY(-2px);
}

.btn-large {
    padding: 1.25rem 3rem;
    font-size: 1.25rem;
}

.btn-block {
    width: 100%;
}

/* === HERO SECTION === */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 80px;
    background: var(--gradient-hero);
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        radial-gradient(circle at 20% 30%, rgba(74, 159, 216, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 70%, rgba(255, 140, 0, 0.15) 0%, transparent 50%);
    animation: pulse 8s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.8; }
}

.hero::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        linear-gradient(90deg, transparent 49%, rgba(255, 255, 255, 0.03) 50%, transparent 51%),
        linear-gradient(0deg, transparent 49%, rgba(255, 255, 255, 0.03) 50%, transparent 51%);
    background-size: 50px 50px;
    opacity: 0.5;
}

.hero-container {
    position: relative;
    z-index: 10;
    max-width: 1400px;
    margin: 0 auto;
    padding: var(--spacing-3xl) var(--spacing-xl);
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-4xl);
    align-items: center;
}

.hero-content h1 {
    color: var(--white);
    margin-bottom: var(--spacing-lg);
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

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

.hero-subtitle {
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.25rem;
    margin-bottom: var(--spacing-xl);
    line-height: 1.8;
}

.hero-stats {
    display: flex;
    gap: var(--spacing-xl);
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-xl);
    border-top: 1px solid rgba(255, 255, 255, 0.2);
}

.stat-item {
    display: flex;
    flex-direction: column;
}

.stat-number {
    font-size: 2rem;
    font-weight: 800;
    background: var(--gradient-accent);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    font-size: 0.875rem;
    color: rgba(255, 255, 255, 0.7);
    margin-top: var(--spacing-xs);
}

/* === SIGNUP CARD - Glassmorphism === */
.signup-card {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    box-shadow: var(--shadow-xl);
    border: 1px solid rgba(255, 255, 255, 0.3);
}

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

.signup-header h3 {
    color: var(--navy-blue);
    font-size: 1.75rem;
    margin-bottom: var(--spacing-sm);
}

.signup-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    background: var(--gradient-accent);
    color: var(--white);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    font-size: 0.875rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
}

.signup-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.form-label {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--gray-700);
}

.form-input {
    padding: 0.875rem 1rem;
    font-size: 1rem;
    border: 2px solid var(--gray-200);
    border-radius: var(--radius-md);
    transition: all 0.2s;
    font-family: inherit;
}

.form-input:focus {
    outline: none;
    border-color: var(--sky-blue);
    box-shadow: 0 0 0 3px rgba(74, 159, 216, 0.1);
}

.features-list {
    list-style: none;
    margin: var(--spacing-lg) 0;
}

.features-list li {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) 0;
    color: var(--gray-700);
    font-size: 0.95rem;
}

.check-icon {
    color: var(--success);
    font-weight: bold;
    font-size: 1.25rem;
}

.trust-signals {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--gray-200);
    font-size: 0.875rem;
    color: var(--gray-700);
}

/* === SECTIONS === */
.section {
    padding: var(--spacing-4xl) var(--spacing-xl);
}

.container {
    max-width: 1400px;
    margin: 0 auto;
}

.section-header {
    text-align: center;
    max-width: 800px;
    margin: 0 auto var(--spacing-3xl) auto;
}

.section-header h2 {
    color: var(--navy-blue);
    margin-bottom: var(--spacing-md);
}

.section-header p {
    font-size: 1.125rem;
    color: var(--gray-700);
}

/* === BENEFITS GRID === */
.benefits-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-xl);
}

.benefit-card {
    padding: var(--spacing-xl);
    background: var(--white);
    border-radius: var(--radius-lg);
    border: 2px solid var(--gray-200);
    transition: all 0.3s;
}

.benefit-card:hover {
    border-color: var(--sky-blue);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.benefit-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
    display: block;
}

.benefit-card h3 {
    color: var(--navy-blue);
    margin-bottom: var(--spacing-sm);
}

.benefit-card p {
    color: var(--gray-700);
    font-size: 1rem;
    line-height: 1.6;
}

/* === COURSE CARDS === */
.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: var(--spacing-xl);
}

.course-card {
    position: relative;
    background: var(--white);
    border-radius: var(--radius-lg);
    overflow: hidden;
    border: 2px solid var(--gray-200);
    transition: all 0.3s;
}

.course-card:hover {
    border-color: var(--navy-blue);
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.course-card.featured {
    border-color: var(--bright-orange);
    background: linear-gradient(135deg, #FFF8F0 0%, var(--white) 100%);
}

.course-badge {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.badge-free {
    background: var(--success);
    color: var(--white);
    box-shadow: 0 2px 8px rgba(0, 200, 83, 0.3);
}

.badge-popular {
    background: var(--gradient-accent);
    color: var(--white);
    box-shadow: 0 2px 8px rgba(255, 140, 0, 0.3);
}

.badge-pro {
    background: var(--gradient-primary);
    color: var(--white);
    box-shadow: 0 2px 8px rgba(0, 61, 122, 0.3);
}

.course-content {
    padding: var(--spacing-xl);
}

.course-card h3 {
    color: var(--navy-blue);
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
}

.course-price {
    font-size: 2rem;
    font-weight: 800;
    background: var(--gradient-accent);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin: var(--spacing-md) 0;
}

.course-description {
    color: var(--gray-700);
    margin-bottom: var(--spacing-lg);
}

.course-features {
    list-style: none;
    margin: var(--spacing-lg) 0;
}

.course-features li {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) 0;
    color: var(--gray-700);
}

/* === CTA SECTION === */
.cta-section {
    background: var(--gradient-hero);
    position: relative;
    overflow: hidden;
}

.cta-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 50% 50%, rgba(255, 140, 0, 0.2) 0%, transparent 70%);
}

.cta-content {
    position: relative;
    z-index: 10;
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.cta-content h2 {
    color: var(--white);
    margin-bottom: var(--spacing-md);
}

.cta-content p {
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.25rem;
    margin-bottom: var(--spacing-xl);
}

/* === FOOTER === */
.footer {
    background: var(--navy-dark);
    color: rgba(255, 255, 255, 0.8);
    padding: var(--spacing-3xl) var(--spacing-xl) var(--spacing-xl);
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer h4 {
    color: var(--white);
    margin-bottom: var(--spacing-md);
}

.footer ul {
    list-style: none;
}

.footer ul li {
    margin-bottom: var(--spacing-sm);
}

.footer a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: color 0.2s;
}

.footer a:hover {
    color: var(--bright-orange);
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: var(--spacing-lg);
    text-align: center;
    font-size: 0.875rem;
}

/* === RESPONSIVE === */
@media (max-width: 1024px) {
    .hero-container {
        grid-template-columns: 1fr;
        gap: var(--spacing-xl);
        text-align: center;
    }
    
    .hero-stats {
        justify-content: center;
    }
}

@media (max-width: 768px) {
    .nav-menu {
        gap: var(--spacing-sm);
        font-size: 0.875rem;
    }
    
    .hero {
        min-height: auto;
        padding: var(--spacing-3xl) 0;
    }
    
    .courses-grid {
        grid-template-columns: 1fr;
    }
    
    .section {
        padding: var(--spacing-2xl) var(--spacing-md);
    }
    
    .btn-large {
        padding: 1rem 2rem;
        font-size: 1.1rem;
    }
}

/* === UTILITIES === */
.text-center { text-align: center; }
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}