/* ==========================================
   RUHERAUM DE - ACOUSTIC GRID DESIGN SYSTEM
   ========================================== */

/* CSS Custom Properties */
:root {
  /* Color Palette */
  --color-graphit: #1A2230;
  --color-tiefblau: #0B1220;
  --color-akzent-blau: #3AA7FF;
  --color-menthol: #20C6B7;
  --color-hellgrau: #A7B0BD;
  --color-white: #FFFFFF;
  --color-off-white: #F8F9FA;
  --color-dark-text: #1A1A1A;
  --color-light-text: #6B7280;

  /* Typography */
  --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  /* Modular Scale */
  --text-xs: 0.75rem;     /* 12px */
  --text-sm: 0.875rem;    /* 14px */
  --text-base: 1rem;      /* 16px */
  --text-lg: 1.125rem;    /* 18px */
  --text-xl: 1.25rem;     /* 20px */
  --text-2xl: 1.5rem;     /* 24px */
  --text-3xl: 1.875rem;   /* 30px */
  --text-4xl: 2.25rem;    /* 36px */
  --text-5xl: 3rem;       /* 48px */

  /* Spacing */
  --spacing-xs: 0.25rem;  /* 4px */
  --spacing-sm: 0.5rem;   /* 8px */
  --spacing-md: 1rem;     /* 16px */
  --spacing-lg: 1.5rem;   /* 24px */
  --spacing-xl: 2rem;     /* 32px */
  --spacing-2xl: 3rem;    /* 48px */
  --spacing-3xl: 4rem;    /* 64px */

  /* Grid System */
  --container-max-width: 1200px;
  --grid-columns: 12;
  --grid-gutter: 1.5rem;  /* 24px */

  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;

  /* Shadows */
  --shadow-sm: 0 2 8px rgba(26, 34, 48, 0.08);
  --shadow-md: 0 4 16px rgba(26, 34, 48, 0.12);
  --shadow-lg: 0 8 24px rgba(26, 34, 48, 0.16);
  --shadow-card: 0 12 28px rgba(0, 0, 0, 0.24);

  /* Transitions */
  --transition-fast: 160ms ease;
  --transition-normal: 200ms ease;
  --transition-slow: 220ms ease;

  /* Acoustic Grid Pattern */
  --grid-color: rgba(58, 167, 255, 0.1);
  --grid-color-accent: rgba(32, 198, 183, 0.15);
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-primary);
  font-size: var(--text-base);
  font-weight: var(--font-weight-normal);
  line-height: 1.6;
  color: var(--color-dark-text);
  background-color: var(--color-off-white);
  overflow-x: hidden;
}

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

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

a:hover {
  color: var(--color-menthol);
}

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

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

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

.section__title {
  font-size: var(--text-4xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-graphit);
  margin-bottom: var(--spacing-md);
  letter-spacing: -0.02em;
}

.section__description {
  font-size: var(--text-lg);
  color: var(--color-light-text);
  max-width: 600px;
  margin: 0 auto;
}

/* Preloader */
.preloader {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, var(--color-tiefblau) 0%, var(--color-graphit) 100%);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  transition: opacity var(--transition-slow), visibility var(--transition-slow);
}

.preloader.hidden {
  opacity: 0;
  visibility: hidden;
}

.preloader p {
  color: var(--color-white);
  font-size: var(--text-lg);
  margin-top: var(--spacing-lg);
  font-weight: var(--font-weight-medium);
}

.sound-waves {
  display: flex;
  gap: var(--spacing-sm);
  align-items: center;
}

.wave {
  width: 4px;
  height: 40px;
  background: var(--color-akzent-blau);
  border-radius: 2px;
  animation: wave-bounce 1.5s ease-in-out infinite;
}

.wave:nth-child(1) {
  animation-delay: 0s;
}

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

.wave:nth-child(3) {
  animation-delay: 0.4s;
}

@keyframes wave-bounce {
  0%, 100% {
    transform: scaleY(1);
    opacity: 0.7;
  }
  50% {
    transform: scaleY(1.5);
    opacity: 1;
  }
}

/* Header */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(26, 34, 48, 0.08);
  z-index: 1000;
  transition: all var(--transition-normal);
}

.header.scrolled {
  box-shadow: var(--shadow-md);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 80px;
}

.nav__logo h1 {
  font-size: var(--text-2xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-graphit);
  letter-spacing: -0.02em;
}

.nav__menu {
  display: flex;
  align-items: center;
}

.nav__list {
  display: flex;
  list-style: none;
  gap: var(--spacing-xl);
}

.nav__link {
  font-weight: var(--font-weight-medium);
  color: var(--color-graphit);
  position: relative;
  transition: color var(--transition-fast);
}

.nav__link:hover,
.nav__link.active {
  color: var(--color-akzent-blau);
}

.nav__link.active::after {
  content: '';
  position: absolute;
  bottom: -8px;
  left: 0;
  width: 100%;
  height: 2px;
  background: var(--color-akzent-blau);
  animation: link-pulse 2s ease-in-out infinite;
}

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

/* Dropdown */
.dropdown {
  position: relative;
}

.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  background: white;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  padding: var(--spacing-md);
  min-width: 250px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: all var(--transition-normal);
  z-index: 100;
}

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

.dropdown-menu a {
  display: block;
  padding: var(--spacing-sm) var(--spacing-md);
  color: var(--color-dark-text);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.dropdown-menu a:hover {
  background: var(--color-off-white);
  color: var(--color-akzent-blau);
}

/* Mobile Menu */
.nav__toggle,
.nav__close {
  display: none;
  cursor: pointer;
  color: var(--color-graphit);
}

/* Hero Section */
.hero {
  background: linear-gradient(135deg, var(--color-tiefblau) 0%, var(--color-graphit) 100%);
  color: var(--color-white);
  padding: 120px 0 var(--spacing-3xl);
  position: relative;
  overflow: hidden;
}

.hero__container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-3xl);
  align-items: center;
}

.hero__content {
  z-index: 2;
}

.hero__title {
  font-size: var(--text-5xl);
  font-weight: var(--font-weight-bold);
  line-height: 1.1;
  margin-bottom: var(--spacing-lg);
  letter-spacing: -0.02em;
}

.hero__description {
  font-size: var(--text-xl);
  line-height: 1.6;
  margin-bottom: var(--spacing-xl);
  color: rgba(255, 255, 255, 0.9);
}

.hero__cta {
  display: flex;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

.hero__grid {
  position: relative;
  height: 400px;
}

.acoustic-grid {
  position: relative;
  width: 100%;
  height: 100%;
  background: rgba(255, 255, 255, 0.02);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.grid-lines {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  opacity: 0.6;
  animation: grid-float 8s ease-in-out infinite;
}

@keyframes grid-float {
  0%, 100% {
    transform: translateY(0) scale(1);
    opacity: 0.6;
  }
  50% {
    transform: translateY(-10px) scale(1.02);
    opacity: 0.8;
  }
}

.sound-pulse {
  position: absolute;
  border: 2px solid var(--color-akzent-blau);
  border-radius: 50%;
  animation: sound-pulse 4s ease-out infinite;
}

.pulse-1 {
  width: 60px;
  height: 60px;
  top: 20%;
  left: 15%;
  animation-delay: 0s;
}

.pulse-2 {
  width: 80px;
  height: 80px;
  top: 40%;
  right: 20%;
  animation-delay: 1s;
}

.pulse-3 {
  width: 100px;
  height: 100px;
  bottom: 30%;
  left: 30%;
  animation-delay: 2s;
}

@keyframes sound-pulse {
  0% {
    transform: scale(0);
    opacity: 1;
  }
  100% {
    transform: scale(1);
    opacity: 0;
  }
}

/* Hero Stats */
.hero__stats {
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  margin-top: var(--spacing-3xl);
  padding: var(--spacing-xl) 0;
}

.stats__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-xl);
  text-align: center;
}

.stat__number {
  font-size: var(--text-4xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-menthol);
  margin-bottom: var(--spacing-sm);
}

.stat__label {
  font-size: var(--text-base);
  color: rgba(255, 255, 255, 0.8);
  font-weight: var(--font-weight-medium);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-md) var(--spacing-xl);
  border-radius: var(--radius-md);
  font-weight: var(--font-weight-semibold);
  font-size: var(--text-base);
  border: none;
  cursor: pointer;
  transition: all var(--transition-normal);
  text-decoration: none;
  line-height: 1;
}

.btn--primary {
  background: var(--color-akzent-blau);
  color: var(--color-white);
  box-shadow: var(--shadow-md);
}

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

.btn--secondary {
  background: transparent;
  color: var(--color-white);
  border: 2px solid rgba(255, 255, 255, 0.3);
}

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

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

.article__card {
  background: var(--color-white);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  transition: all var(--transition-normal);
  cursor: pointer;
}

.article__card:hover {
  transform: translateY(-4px);
  box-shadow: 0 20 40px rgba(0, 0, 0, 0.32);
}

.article__card.featured {
  grid-column: span 2;
}

.article__image {
  position: relative;
  height: 200px;
  overflow: hidden;
}

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

.article__card:hover .article__image img {
  transform: scale(1.05);
}

.article__content {
  padding: var(--spacing-lg);
}

.article__category {
  display: inline-block;
  background: var(--color-akzent-blau);
  color: var(--color-white);
  padding: var(--spacing-xs) var(--spacing-md);
  border-radius: var(--radius-sm);
  font-size: var(--text-xs);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: var(--spacing-md);
}

.article__title {
  font-size: var(--text-xl);
  font-weight: var(--font-weight-semibold);
  color: var(--color-graphit);
  margin-bottom: var(--spacing-md);
  line-height: 1.4;
}

.article__excerpt {
  color: var(--color-light-text);
  line-height: 1.6;
  margin-bottom: var(--spacing-lg);
}

.article__meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.badge {
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-sm);
  font-size: var(--text-xs);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.badge--beginner {
  background: var(--color-menthol);
  color: var(--color-white);
}

.badge--practice {
  background: var(--color-akzent-blau);
  color: var(--color-white);
}

.badge--diy {
  background: var(--color-hellgrau);
  color: var(--color-white);
}

/* Filter Chips */
.filter-chips {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-xl);
  justify-content: center;
}

.chip {
  padding: var(--spacing-sm) var(--spacing-lg);
  border: 2px solid var(--color-hellgrau);
  background: transparent;
  color: var(--color-graphit);
  border-radius: var(--radius-xl);
  cursor: pointer;
  transition: all var(--transition-fast);
  font-weight: var(--font-weight-medium);
  font-size: var(--text-sm);
}

.chip:hover,
.chip.active {
  background: var(--color-akzent-blau);
  border-color: var(--color-akzent-blau);
  color: var(--color-white);
}

/* Benefits Section */
.benefits__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: var(--spacing-xl);
}

.benefit__item {
  background: var(--color-white);
  padding: var(--spacing-xl);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-normal);
}

.benefit__item:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.benefit__icon {
  width: 64px;
  height: 64px;
  background: linear-gradient(135deg, var(--color-akzent-blau), var(--color-menthol));
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-white);
  margin-bottom: var(--spacing-lg);
}

.benefit__title {
  font-size: var(--text-xl);
  font-weight: var(--font-weight-semibold);
  color: var(--color-graphit);
  margin-bottom: var(--spacing-md);
}

.benefit__description {
  color: var(--color-light-text);
  line-height: 1.6;
}

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

.testimonial__card {
  background: var(--color-white);
  padding: var(--spacing-xl);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  position: relative;
}

.testimonial__rating {
  margin-bottom: var(--spacing-lg);
}

.stars {
  color: #FFD700;
  font-size: var(--text-lg);
}

.testimonial__quote {
  font-style: italic;
  color: var(--color-light-text);
  line-height: 1.6;
  margin-bottom: var(--spacing-lg);
  font-size: var(--text-base);
}

.testimonial__author strong {
  color: var(--color-graphit);
  display: block;
}

.testimonial__author span {
  color: var(--color-hellgrau);
  font-size: var(--text-sm);
}

/* Categories */
.categories__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-xl);
}

.category__card {
  background: var(--color-white);
  padding: var(--spacing-xl);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  transition: all var(--transition-normal);
  text-decoration: none;
  display: block;
}

.category__card:hover {
  transform: translateY(-4px);
  box-shadow: 0 20 40px rgba(0, 0, 0, 0.32);
  color: inherit;
}

.category__icon {
  width: 80px;
  height: 80px;
  background: linear-gradient(135deg, var(--color-akzent-blau), var(--color-menthol));
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-white);
  margin-bottom: var(--spacing-lg);
}

.category__title {
  font-size: var(--text-xl);
  font-weight: var(--font-weight-semibold);
  color: var(--color-graphit);
  margin-bottom: var(--spacing-md);
}

.category__description {
  color: var(--color-light-text);
  line-height: 1.6;
  margin-bottom: var(--spacing-lg);
}

.category__count {
  color: var(--color-akzent-blau);
  font-weight: var(--font-weight-semibold);
  font-size: var(--text-sm);
}

/* Newsletter */
.newsletter {
  background: linear-gradient(135deg, var(--color-graphit), var(--color-tiefblau));
  color: var(--color-white);
}

.newsletter__content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-3xl);
  align-items: start;
}

.newsletter__title {
  font-size: var(--text-4xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-lg);
  letter-spacing: -0.02em;
}

.newsletter__description {
  font-size: var(--text-lg);
  line-height: 1.6;
  margin-bottom: var(--spacing-xl);
  color: rgba(255, 255, 255, 0.9);
}

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

.newsletter__benefits .benefit {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  color: rgba(255, 255, 255, 0.9);
}

.newsletter__benefits .benefit svg {
  color: var(--color-menthol);
  flex-shrink: 0;
}

/* Forms */
.form__group {
  margin-bottom: var(--spacing-lg);
}

.form__group label {
  display: block;
  margin-bottom: var(--spacing-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-white);
}

.form__group input,
.form__group select,
.form__group textarea {
  width: 100%;
  padding: var(--spacing-md);
  border: 2px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.1);
  color: var(--color-white);
  font-size: var(--text-base);
  transition: all var(--transition-fast);
}

.form__group input::placeholder,
.form__group textarea::placeholder {
  color: rgba(255, 255, 255, 0.6);
}

.form__group input:focus,
.form__group select:focus,
.form__group textarea:focus {
  outline: none;
  border-color: var(--color-akzent-blau);
  background: rgba(255, 255, 255, 0.15);
}

.form__group select option {
  background: var(--color-graphit);
  color: var(--color-white);
}

/* Footer */
.footer {
  background: var(--color-graphit);
  color: var(--color-white);
  padding: var(--spacing-3xl) 0 var(--spacing-xl);
}

.footer__content {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--spacing-3xl);
  margin-bottom: var(--spacing-xl);
}

.footer__title {
  font-size: var(--text-2xl);
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-md);
  letter-spacing: -0.02em;
}

.footer__description {
  color: rgba(255, 255, 255, 0.8);
  line-height: 1.6;
  margin-bottom: var(--spacing-lg);
}

.footer__subtitle {
  font-size: var(--text-lg);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-md);
}

.footer__links {
  list-style: none;
}

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

.footer__links a {
  color: rgba(255, 255, 255, 0.8);
  transition: color var(--transition-fast);
}

.footer__links a:hover {
  color: var(--color-akzent-blau);
}

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

.contact__item {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  color: rgba(255, 255, 255, 0.8);
}

.contact__item svg {
  color: var(--color-akzent-blau);
  flex-shrink: 0;
}

.contact__item a {
  color: rgba(255, 255, 255, 0.8);
}

.contact__item a:hover {
  color: var(--color-akzent-blau);
}

.footer__bottom {
  text-align: center;
  padding-top: var(--spacing-xl);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  color: rgba(255, 255, 255, 0.6);
}

/* Scroll Reveal Animation */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: all var(--transition-slow);
}

.reveal.revealed {
  opacity: 1;
  transform: translateY(0);
}

/* Responsive Design */
@media (max-width: 1024px) {
  .hero__container,
  .newsletter__content {
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
  }
  
  .hero__grid {
    height: 300px;
  }
  
  .article__card.featured {
    grid-column: span 1;
  }
  
  .footer__content {
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
  }
}

@media (max-width: 768px) {
  :root {
    --spacing-3xl: 2.5rem;
    --text-4xl: 2rem;
    --text-5xl: 2.5rem;
  }
  
  .nav__menu {
    position: fixed;
    top: 0;
    right: -100%;
    width: 300px;
    height: 100vh;
    background: var(--color-white);
    flex-direction: column;
    padding: var(--spacing-3xl) var(--spacing-lg);
    transition: right var(--transition-normal);
    z-index: 1001;
    box-shadow: var(--shadow-lg);
  }
  
  .nav__menu.show {
    right: 0;
  }
  
  .nav__list {
    flex-direction: column;
    width: 100%;
    gap: var(--spacing-lg);
  }
  
  .nav__toggle {
    display: block;
  }
  
  .nav__close {
    display: block;
    position: absolute;
    top: var(--spacing-lg);
    right: var(--spacing-lg);
  }
  
  .hero__title {
    font-size: var(--text-4xl);
  }
  
  .hero__cta {
    justify-content: center;
  }
  
  .section__title {
    font-size: var(--text-3xl);
  }
  
  .articles__grid,
  .benefits__grid,
  .categories__grid {
    grid-template-columns: 1fr;
  }
  
  .stats__grid {
    grid-template-columns: 1fr;
  }
  
  .footer__content {
    grid-template-columns: 1fr;
    text-align: center;
  }
  
  .newsletter__benefits {
    align-items: center;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 var(--spacing-md);
  }
  
  .hero__title {
    font-size: var(--text-3xl);
  }
  
  .hero__cta {
    flex-direction: column;
  }
  
  .btn {
    width: 100%;
  }
  
  .filter-chips {
    justify-content: flex-start;
  }
  
  .chip {
    font-size: var(--text-xs);
    padding: var(--spacing-xs) var(--spacing-md);
  }
}