/* ==========================================
   DESIGN SYSTEM - Grünbuch Energieeffizienz
   Modernes, seriöses Design für Nachhaltigkeit
   ========================================== */

/* CSS Variables / Design Tokens */
:root {
    /* Colors - Professional Green Palette */
    --color-primary: #2d5016;
    --color-primary-light: #4a7c2b;
    --color-primary-dark: #1a3009;
    --color-accent: #7cb342;
    --color-accent-light: #9ccc65;

    /* Neutral Colors */
    --color-white: #ffffff;
    --color-black: #0a0a0a;
    --color-gray-50: #fafafa;
    --color-gray-100: #f5f5f5;
    --color-gray-200: #e5e5e5;
    --color-gray-300: #d4d4d4;
    --color-gray-400: #a3a3a3;
    --color-gray-500: #737373;
    --color-gray-600: #525252;
    --color-gray-700: #404040;
    --color-gray-800: #262626;
    --color-gray-900: #171717;

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

    /* Font Sizes */
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 1.875rem;
    --text-4xl: 2.25rem;
    --text-5xl: 3rem;
    --text-6xl: 3.75rem;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    --spacing-3xl: 6rem;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1);

    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;

    /* Layout */
    --max-width: 1280px;
    --header-height: 80px;
}

/* ==========================================
   RESET & BASE STYLES
   ========================================== */

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

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

body {
    font-family: var(--font-primary);
    font-size: var(--text-base);
    line-height: 1.6;
    color: var(--color-gray-700);
    background-color: var(--color-white);
}

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

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

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

ul, ol {
    list-style: none;
}

/* ==========================================
   TYPOGRAPHY
   ========================================== */

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: 700;
    line-height: 1.2;
    color: var(--color-gray-900);
    margin-bottom: var(--spacing-md);
}

h1 { font-size: var(--text-5xl); }
h2 { font-size: var(--text-4xl); }
h3 { font-size: var(--text-3xl); }
h4 { font-size: var(--text-2xl); }
h5 { font-size: var(--text-xl); }
h6 { font-size: var(--text-lg); }

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

.highlight {
    color: var(--color-primary);
    position: relative;
}

/* ==========================================
   LAYOUT
   ========================================== */

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* ==========================================
   HEADER & NAVIGATION
   ========================================== */

.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.nav-wrapper {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: var(--header-height);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: var(--text-xl);
    font-weight: 700;
    color: var(--color-primary);
}

.logo-icon {
    font-size: var(--text-2xl);
}

.logo-text {
    font-family: var(--font-display);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
}

.nav-link {
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--color-gray-700);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
}

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

.nav-cta {
    background: var(--color-primary);
    color: var(--color-white);
}

.nav-cta:hover {
    background: var(--color-primary-dark);
    color: var(--color-white);
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    padding: var(--spacing-xs);
}

.mobile-menu-toggle span {
    width: 24px;
    height: 2px;
    background: var(--color-gray-700);
    border-radius: var(--radius-full);
    transition: all var(--transition-base);
}

/* ==========================================
   HERO SECTION
   ========================================== */

.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 100%);
    background-image:
        linear-gradient(135deg, rgba(29, 48, 9, 0.9) 0%, rgba(45, 80, 22, 0.85) 100%),
        url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1440 320"><path fill="%234a7c2b" fill-opacity="0.1" d="M0,96L48,112C96,128,192,160,288,160C384,160,480,128,576,122.7C672,117,768,139,864,154.7C960,171,1056,181,1152,165.3C1248,149,1344,107,1392,85.3L1440,64L1440,320L1392,320C1344,320,1248,320,1152,320C1056,320,960,320,864,320C768,320,672,320,576,320C480,320,384,320,288,320C192,320,96,320,48,320L0,320Z"></path></svg>');
    background-size: cover;
    background-position: center;
    overflow: hidden;
    margin-top: var(--header-height);
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    padding: var(--spacing-3xl) 0;
}

.hero-title {
    font-size: clamp(var(--text-4xl), 5vw, var(--text-6xl));
    color: var(--color-white);
    margin-bottom: var(--spacing-md);
}

.hero-title .highlight {
    color: var(--color-accent-light);
}

.hero-subtitle {
    font-size: clamp(var(--text-lg), 2vw, var(--text-xl));
    color: rgba(255, 255, 255, 0.9);
    max-width: 700px;
    margin: 0 auto var(--spacing-xl);
    line-height: 1.7;
}

.hero-actions {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
}

.scroll-indicator {
    position: absolute;
    bottom: var(--spacing-xl);
    left: 50%;
    transform: translateX(-50%);
    color: var(--color-white);
    font-size: var(--text-2xl);
    animation: bounce 2s infinite;
}

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

/* ==========================================
   BUTTONS
   ========================================== */

.btn {
    display: inline-block;
    padding: 1rem 2rem;
    font-size: var(--text-base);
    font-weight: 600;
    border-radius: var(--radius-lg);
    transition: all var(--transition-base);
    cursor: pointer;
    border: 2px solid transparent;
    text-align: center;
}

.btn-primary {
    background: var(--color-accent);
    color: var(--color-white);
}

.btn-primary:hover {
    background: var(--color-accent-light);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: transparent;
    color: var(--color-white);
    border-color: var(--color-white);
}

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

.btn-outline {
    background: transparent;
    color: var(--color-primary);
    border-color: var(--color-primary);
}

.btn-outline:hover {
    background: var(--color-primary);
    color: var(--color-white);
}

.btn-white {
    background: var(--color-white);
    color: var(--color-primary);
}

.btn-white:hover {
    background: var(--color-gray-100);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

/* ==========================================
   SECTIONS
   ========================================== */

section {
    padding: var(--spacing-3xl) 0;
}

.section-header {
    text-align: center;
    max-width: 800px;
    margin: 0 auto var(--spacing-2xl);
}

.section-tag {
    display: inline-block;
    font-size: var(--text-sm);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-primary);
    background: rgba(124, 179, 66, 0.1);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    margin-bottom: var(--spacing-md);
}

.section-title {
    font-size: clamp(var(--text-3xl), 4vw, var(--text-4xl));
    margin-bottom: var(--spacing-md);
}

.section-subtitle {
    font-size: var(--text-lg);
    color: var(--color-gray-600);
    line-height: 1.7;
}

/* ==========================================
   FEATURES SECTION
   ========================================== */

.features {
    background: var(--color-gray-50);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
}

.feature-card {
    background: var(--color-white);
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.feature-icon {
    font-size: var(--text-5xl);
    margin-bottom: var(--spacing-md);
}

.feature-title {
    font-size: var(--text-xl);
    margin-bottom: var(--spacing-sm);
    color: var(--color-gray-900);
}

.feature-description {
    color: var(--color-gray-600);
    line-height: 1.7;
}

/* ==========================================
   ABOUT SECTION
   ========================================== */

.about-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: var(--spacing-2xl);
    align-items: center;
}

.about-image img {
    width: 100%;
    height: 500px;
    object-fit: cover;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
}

.about-text {
    font-size: var(--text-lg);
    color: var(--color-gray-600);
    line-height: 1.7;
    margin-bottom: var(--spacing-md);
}

.about-list {
    margin: var(--spacing-xl) 0;
}

.about-list li {
    position: relative;
    padding-left: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
    font-size: var(--text-lg);
}

.about-list li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--color-accent);
    font-weight: 700;
}

/* ==========================================
   SERVICES SECTION
   ========================================== */

.services {
    background: var(--color-primary-dark);
    color: var(--color-white);
}

.services .section-tag {
    background: rgba(124, 179, 66, 0.2);
    color: var(--color-accent-light);
}

.services .section-title,
.services .section-subtitle {
    color: var(--color-white);
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
}

.service-card {
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(10px);
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: all var(--transition-base);
}

.service-card:hover {
    background: rgba(255, 255, 255, 0.1);
    transform: translateY(-5px);
}

.service-number {
    font-size: var(--text-3xl);
    font-weight: 700;
    color: var(--color-accent-light);
    margin-bottom: var(--spacing-md);
    font-family: var(--font-display);
}

.service-title {
    font-size: var(--text-xl);
    color: var(--color-white);
    margin-bottom: var(--spacing-sm);
}

.service-description {
    color: rgba(255, 255, 255, 0.8);
    line-height: 1.7;
    margin-bottom: var(--spacing-md);
}

.service-link {
    color: var(--color-accent-light);
    font-weight: 600;
    display: inline-block;
    transition: all var(--transition-base);
}

.service-link:hover {
    transform: translateX(5px);
}

/* ==========================================
   BLOG SECTION
   ========================================== */

.blog-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: var(--spacing-xl);
}

.blog-card {
    background: var(--color-white);
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.blog-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.blog-image {
    position: relative;
    height: 250px;
    overflow: hidden;
}

.blog-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-slow);
}

.blog-card:hover .blog-image img {
    transform: scale(1.05);
}

.blog-category {
    position: absolute;
    top: var(--spacing-md);
    left: var(--spacing-md);
    background: var(--color-accent);
    color: var(--color-white);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-full);
    font-size: var(--text-sm);
    font-weight: 600;
}

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

.blog-date {
    display: block;
    font-size: var(--text-sm);
    color: var(--color-gray-500);
    margin-bottom: var(--spacing-sm);
}

.blog-title {
    font-size: var(--text-xl);
    margin-bottom: var(--spacing-sm);
}

.blog-title a {
    color: var(--color-gray-900);
    transition: color var(--transition-base);
}

.blog-title a:hover {
    color: var(--color-primary);
}

.blog-excerpt {
    color: var(--color-gray-600);
    line-height: 1.7;
    margin-bottom: var(--spacing-md);
}

.blog-link {
    color: var(--color-primary);
    font-weight: 600;
    display: inline-block;
    transition: all var(--transition-base);
}

.blog-link:hover {
    transform: translateX(5px);
}

.blog-cta {
    text-align: center;
    margin-top: var(--spacing-2xl);
}

/* ==========================================
   CTA SECTION
   ========================================== */

.cta-section {
    background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-primary) 100%);
    color: var(--color-white);
    text-align: center;
}

.cta-title {
    font-size: clamp(var(--text-3xl), 4vw, var(--text-4xl));
    color: var(--color-white);
    margin-bottom: var(--spacing-md);
}

.cta-text {
    font-size: var(--text-xl);
    color: rgba(255, 255, 255, 0.9);
    max-width: 700px;
    margin: 0 auto var(--spacing-xl);
    line-height: 1.7;
}

/* ==========================================
   FOOTER
   ========================================== */

.footer {
    background: var(--color-gray-900);
    color: var(--color-gray-400);
    padding: var(--spacing-3xl) 0 var(--spacing-lg);
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-2xl);
    margin-bottom: var(--spacing-2xl);
}

.footer-title {
    font-size: var(--text-xl);
    color: var(--color-white);
    margin-bottom: var(--spacing-md);
}

.footer-text {
    line-height: 1.7;
    margin-bottom: var(--spacing-md);
}

.footer-social {
    display: flex;
    gap: var(--spacing-md);
}

.footer-social a {
    color: var(--color-gray-400);
    transition: color var(--transition-base);
}

.footer-social a:hover {
    color: var(--color-accent);
}

.footer-heading {
    font-size: var(--text-lg);
    font-weight: 600;
    color: var(--color-white);
    margin-bottom: var(--spacing-md);
}

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

.footer-links a {
    color: var(--color-gray-400);
    transition: color var(--transition-base);
}

.footer-links a:hover {
    color: var(--color-accent);
}

.footer-bottom {
    border-top: 1px solid var(--color-gray-800);
    padding-top: var(--spacing-lg);
    text-align: center;
    font-size: var(--text-sm);
}

/* ==========================================
   RESPONSIVE
   ========================================== */

@media (max-width: 768px) {
    :root {
        --header-height: 70px;
    }

    .mobile-menu-toggle {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        top: var(--header-height);
        left: 0;
        right: 0;
        background: var(--color-white);
        flex-direction: column;
        padding: var(--spacing-lg);
        box-shadow: var(--shadow-lg);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all var(--transition-base);
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .hero-actions {
        flex-direction: column;
    }

    .about-grid,
    .features-grid,
    .services-grid,
    .blog-grid {
        grid-template-columns: 1fr;
    }

    .about-image img {
        height: 300px;
    }
}

@media (max-width: 480px) {
    .btn {
        width: 100%;
    }
}