/* ============================================================
   BLOCX Ventilation - Main Stylesheet
   Premium design inspired by Himpel (himpel.com)
   ============================================================ */

/* ------------------------------------------------------------
   1. CSS Custom Properties (Design Tokens)
   ------------------------------------------------------------ */
:root {
  /* Brand Colors */
  --color-navy: #0a1628;
  --color-navy-light: #132240;
  --color-teal: #0d9b7a;
  --color-teal-light: #10b892;
  --color-teal-dark: #0a7d62;

  /* Neutrals */
  --color-white: #ffffff;
  --color-gray-50: #f8f9fa;
  --color-gray-100: #f1f3f5;
  --color-gray-200: #e9ecef;
  --color-gray-300: #dee2e6;
  --color-gray-400: #adb5bd;
  --color-gray-500: #868e96;
  --color-gray-600: #495057;
  --color-gray-700: #343a40;
  --color-gray-800: #212529;

  /* Text */
  --color-text: #212529;
  --color-text-light: #868e96;

  /* Typography */
  --font-en: 'Inter', sans-serif;
  --font-kr: 'Noto Sans KR', sans-serif;

  /* Layout */
  --header-height: 80px;
  --header-height-shrink: 60px;

  /* Motion */
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);

  /* Elevation */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.12);

  /* Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
}


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

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

body {
  font-family: var(--font-kr);
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-text);
  background-color: var(--color-white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

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

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

ul, ol {
  list-style: none;
}

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

input, textarea, select {
  font-family: inherit;
  font-size: inherit;
}


/* ------------------------------------------------------------
   3. Utility: Container
   ------------------------------------------------------------ */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}


/* ------------------------------------------------------------
   4. Header
   ------------------------------------------------------------ */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-height);
  z-index: 1000;
  transition: var(--transition);
  background: transparent;
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Logo */
.header__logo {
  font-family: var(--font-en);
  font-size: 1.5rem;
  font-weight: 800;
  letter-spacing: 3px;
  color: var(--color-white);
  transition: var(--transition);
  text-transform: uppercase;
}

.header__logo span {
  color: var(--color-teal-light);
}

/* Nav Links */
.header__nav {
  display: flex;
  align-items: center;
  gap: 36px;
}

.header__nav-link {
  font-family: var(--font-en);
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--color-white);
  position: relative;
  padding: 4px 0;
  transition: var(--transition);
}

.header__nav-link::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-teal-light);
  transition: width 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.header__nav-link:hover::after,
.header__nav-link.active::after {
  width: 100%;
}

/* Scrolled State */
.header--scrolled {
  background: var(--color-white);
  height: var(--header-height-shrink);
  box-shadow: var(--shadow-sm);
}

.header--scrolled .header__logo {
  color: var(--color-navy);
}

.header--scrolled .header__nav-link {
  color: var(--color-gray-700);
}

.header--scrolled .header__nav-link:hover {
  color: var(--color-teal);
}

/* Hamburger */
.header__hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 6px;
  width: 28px;
  height: 28px;
  cursor: pointer;
  z-index: 1001;
}

.header__hamburger span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--color-white);
  transition: var(--transition);
  transform-origin: center;
}

.header--scrolled .header__hamburger span {
  background: var(--color-navy);
}

.header__hamburger.active span:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}

.header__hamburger.active span:nth-child(2) {
  opacity: 0;
  transform: scaleX(0);
}

.header__hamburger.active span:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

/* Mobile Menu Overlay */
.mobile-menu {
  position: fixed;
  inset: 0;
  background: var(--color-navy);
  z-index: 999;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 32px;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
}

.mobile-menu.active {
  opacity: 1;
  visibility: visible;
}

.mobile-menu__link {
  font-family: var(--font-en);
  font-size: 1.5rem;
  font-weight: 600;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--color-white);
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.4s ease, transform 0.4s ease, color 0.3s ease;
}

.mobile-menu.active .mobile-menu__link {
  opacity: 1;
  transform: translateY(0);
}

.mobile-menu__link:hover {
  color: var(--color-teal-light);
}


/* ------------------------------------------------------------
   5. Hero Section
   ------------------------------------------------------------ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

/* Background Layer 1: Navy gradient base */
.hero__bg-base {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    180deg,
    var(--color-navy) 0%,
    #0e2240 40%,
    #102a4a 70%,
    #0a3a5e 100%
  );
  z-index: 1;
}

/* Background Layer 2: Mountain silhouettes */
.hero__bg-mountains {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 60%;
  z-index: 2;
}

.hero__mountain--back {
  position: absolute;
  bottom: 0;
  left: -5%;
  width: 110%;
  height: 70%;
  background: #0d1e36;
  clip-path: polygon(0 100%, 0 60%, 8% 45%, 18% 55%, 28% 30%, 40% 50%, 50% 20%, 60% 40%, 72% 25%, 82% 45%, 92% 35%, 100% 50%, 100% 100%);
}

.hero__mountain--mid {
  position: absolute;
  bottom: 0;
  left: -5%;
  width: 110%;
  height: 55%;
  background: #0f2a42;
  clip-path: polygon(0 100%, 0 70%, 10% 50%, 22% 65%, 35% 35%, 45% 55%, 55% 30%, 65% 50%, 75% 40%, 88% 55%, 100% 45%, 100% 100%);
}

.hero__mountain--front {
  position: absolute;
  bottom: 0;
  left: -5%;
  width: 110%;
  height: 40%;
  background: #112e3e;
  clip-path: polygon(0 100%, 0 65%, 12% 50%, 25% 60%, 38% 40%, 50% 55%, 62% 45%, 75% 55%, 88% 40%, 100% 55%, 100% 100%);
}

/* Background Layer 3: Trees */
.hero__bg-trees {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 35%;
  z-index: 3;
}

.hero__tree {
  position: absolute;
  bottom: 0;
}

.hero__tree::before {
  content: '';
  display: block;
  width: 0;
  height: 0;
  border-left: var(--tree-width, 20px) solid transparent;
  border-right: var(--tree-width, 20px) solid transparent;
  border-bottom: var(--tree-height, 60px) solid var(--tree-color, #0a3a4a);
}

.hero__tree::after {
  content: '';
  display: block;
  width: 4px;
  height: 15px;
  background: var(--tree-color, #0a3a4a);
  margin: 0 auto;
}

.hero__tree--1 { left: 5%; --tree-width: 18px; --tree-height: 55px; --tree-color: #0d3d4d; }
.hero__tree--2 { left: 12%; --tree-width: 22px; --tree-height: 70px; --tree-color: #0b3545; }
.hero__tree--3 { left: 20%; --tree-width: 16px; --tree-height: 50px; --tree-color: #0e4050; }
.hero__tree--4 { left: 75%; --tree-width: 20px; --tree-height: 65px; --tree-color: #0c3848; }
.hero__tree--5 { left: 85%; --tree-width: 24px; --tree-height: 75px; --tree-color: #0a3240; }
.hero__tree--6 { left: 92%; --tree-width: 15px; --tree-height: 48px; --tree-color: #0d3d4d; }

/* Background Layer 4: Gradient overlay */
.hero__bg-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(
    180deg,
    rgba(10, 22, 40, 0.3) 0%,
    rgba(10, 22, 40, 0.1) 40%,
    rgba(10, 22, 40, 0.5) 100%
  );
  z-index: 4;
}

/* Canvas overlay for landing.js */
#hero-canvas {
  position: absolute;
  inset: 0;
  z-index: 6;
  pointer-events: none;
}

/* Floating particles container */
.hero__particles {
  position: absolute;
  inset: 0;
  z-index: 5;
  overflow: hidden;
}

/* Hero Content */
.hero__content {
  position: relative;
  z-index: 10;
  text-align: center;
  padding: 0 24px;
  max-width: 900px;
}

.hero__title {
  font-family: var(--font-en);
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  font-weight: 700;
  color: var(--color-white);
  line-height: 1.15;
  margin-bottom: 20px;
  letter-spacing: -0.5px;
}

.hero__title-kr {
  display: block;
  font-family: var(--font-kr);
  font-size: clamp(1.2rem, 2.5vw, 1.6rem);
  font-weight: 400;
  color: rgba(255, 255, 255, 0.7);
  margin-top: 12px;
  letter-spacing: 0;
}

.hero__subtitle {
  font-size: clamp(1rem, 2vw, 1.25rem);
  font-weight: 300;
  color: rgba(255, 255, 255, 0.65);
  line-height: 1.8;
  margin-bottom: 40px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

/* CTA Buttons */
.hero__cta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 36px;
  font-family: var(--font-kr);
  font-size: 0.95rem;
  font-weight: 500;
  border-radius: 50px;
  transition: var(--transition);
  cursor: pointer;
  letter-spacing: 0.5px;
}

.btn--primary {
  background: var(--color-teal);
  color: var(--color-white);
  border: 2px solid var(--color-teal);
}

.btn--primary:hover {
  background: var(--color-teal-dark);
  border-color: var(--color-teal-dark);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(13, 155, 122, 0.35);
}

.btn--outline {
  background: transparent;
  color: var(--color-white);
  border: 2px solid rgba(255, 255, 255, 0.4);
}

.btn--outline:hover {
  border-color: var(--color-white);
  background: rgba(255, 255, 255, 0.1);
  transform: translateY(-2px);
}

/* Scroll Indicator */
.hero__scroll {
  position: absolute;
  bottom: 40px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 10;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  cursor: pointer;
}

.hero__scroll-text {
  font-family: var(--font-en);
  font-size: 0.7rem;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: rgba(255, 255, 255, 0.5);
}

.hero__scroll-icon {
  width: 24px;
  height: 40px;
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-radius: 12px;
  position: relative;
}

.hero__scroll-icon::before {
  content: '';
  position: absolute;
  top: 8px;
  left: 50%;
  transform: translateX(-50%);
  width: 4px;
  height: 8px;
  background: rgba(255, 255, 255, 0.6);
  border-radius: 2px;
}


/* ------------------------------------------------------------
   6. Section Common
   ------------------------------------------------------------ */
.section {
  padding: 120px 0;
}

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

.section--dark {
  background: var(--color-navy);
  color: var(--color-white);
}

.section__header {
  text-align: center;
  margin-bottom: 64px;
}

.section__label {
  font-family: var(--font-en);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--color-teal);
  margin-bottom: 12px;
  display: block;
}

.section--dark .section__label {
  color: var(--color-teal-light);
}

.section__title {
  font-family: var(--font-kr);
  font-size: clamp(1.8rem, 3.5vw, 2.5rem);
  font-weight: 700;
  color: var(--color-navy);
  line-height: 1.3;
}

.section--dark .section__title {
  color: var(--color-white);
}

.section__subtitle {
  font-size: 1.05rem;
  color: var(--color-text-light);
  margin-top: 16px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.8;
}

.section--dark .section__subtitle {
  color: rgba(255, 255, 255, 0.6);
}


/* ------------------------------------------------------------
   7. About Section
   ------------------------------------------------------------ */
.about__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.about__card {
  background: var(--color-white);
  border-radius: var(--radius-md);
  padding: 48px 32px;
  text-align: center;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  border: 1px solid var(--color-gray-200);
}

.about__card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
  border-color: transparent;
}

.about__icon {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-teal), var(--color-teal-light));
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 24px;
  color: var(--color-white);
  font-size: 1.5rem;
  box-shadow: 0 4px 15px rgba(13, 155, 122, 0.3);
}

.about__icon svg {
  width: 32px;
  height: 32px;
  fill: currentColor;
}

.about__card-title {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-navy);
  margin-bottom: 12px;
}

.about__card-desc {
  font-size: 0.95rem;
  color: var(--color-text-light);
  line-height: 1.8;
}


/* ------------------------------------------------------------
   8. Products Section
   ------------------------------------------------------------ */

/* Filter Tabs */
.products__filter {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin-bottom: 48px;
  flex-wrap: wrap;
}

.products__filter-btn {
  padding: 10px 24px;
  font-size: 0.85rem;
  font-weight: 500;
  border-radius: 50px;
  color: var(--color-gray-600);
  background: var(--color-gray-100);
  border: 1px solid var(--color-gray-200);
  transition: var(--transition);
  white-space: nowrap;
}

.products__filter-btn:hover {
  background: var(--color-gray-200);
  color: var(--color-gray-700);
}

.products__filter-btn.active {
  background: var(--color-teal);
  color: var(--color-white);
  border-color: var(--color-teal);
}

/* Product Grid */
.products__grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 24px;
}

/* Product Card */
.product-card {
  background: var(--color-white);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-gray-200);
  transition: var(--transition);
  cursor: pointer;
}

.product-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-lg);
  border-color: transparent;
}

.product-card__image {
  position: relative;
  aspect-ratio: 4 / 3;
  background: var(--color-gray-100);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
  overflow: hidden;
}

.product-card__image img {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
  transition: transform 0.4s ease;
}

.product-card:hover .product-card__image img {
  transform: scale(1.05);
}

.product-card__badge {
  position: absolute;
  top: 16px;
  left: 16px;
  padding: 4px 14px;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.5px;
  border-radius: 50px;
  background: var(--color-teal);
  color: var(--color-white);
  text-transform: uppercase;
}

.product-card__body {
  padding: 24px;
}

.product-card__category {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-teal);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 6px;
}

.product-card__name {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-navy);
  margin-bottom: 8px;
  line-height: 1.4;
}

.product-card__spec {
  font-size: 0.85rem;
  color: var(--color-text-light);
  line-height: 1.6;
}

.product-card__more {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--color-teal);
  margin-top: 12px;
  transition: var(--transition);
}

.product-card__more:hover {
  gap: 10px;
}

.product-card__more::after {
  content: '\2192';
}


/* ------------------------------------------------------------
   9. Technology Section
   ------------------------------------------------------------ */
.tech__diagram {
  max-width: 800px;
  margin: 0 auto 64px;
}

.tech__diagram svg {
  width: 100%;
  height: auto;
}

.tech__benefits {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.tech__card {
  background: rgba(255, 255, 255, 0.06);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-md);
  padding: 36px 28px;
  text-align: center;
  transition: var(--transition);
}

.tech__card:hover {
  background: rgba(255, 255, 255, 0.1);
  transform: translateY(-4px);
}

.tech__card-icon {
  font-size: 2.5rem;
  margin-bottom: 16px;
}

.tech__card-value {
  font-family: var(--font-en);
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-teal-light);
  margin-bottom: 8px;
}

.tech__card-label {
  font-size: 0.95rem;
  color: rgba(255, 255, 255, 0.7);
}


/* ------------------------------------------------------------
   10. History Section
   ------------------------------------------------------------ */
.history__layout {
  display: grid;
  grid-template-columns: 1.5fr 1fr;
  gap: 64px;
  align-items: start;
}

/* Timeline */
.timeline {
  position: relative;
  padding-left: 40px;
}

.timeline::before {
  content: '';
  position: absolute;
  top: 0;
  left: 15px;
  width: 2px;
  height: 100%;
  background: var(--color-gray-200);
}

.timeline__item {
  position: relative;
  padding-bottom: 40px;
}

.timeline__item:last-child {
  padding-bottom: 0;
}

.timeline__dot {
  position: absolute;
  left: -33px;
  top: 4px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--color-teal);
  border: 3px solid var(--color-white);
  box-shadow: 0 0 0 2px var(--color-teal);
}

.timeline__year {
  display: inline-block;
  padding: 3px 14px;
  font-family: var(--font-en);
  font-size: 0.8rem;
  font-weight: 600;
  background: var(--color-teal);
  color: var(--color-white);
  border-radius: 50px;
  margin-bottom: 8px;
}

.timeline__text {
  font-size: 0.95rem;
  color: var(--color-gray-600);
  line-height: 1.7;
}

/* Certifications */
.certs__title {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--color-navy);
  margin-bottom: 24px;
}

.cert-badge {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 16px 20px;
  background: var(--color-white);
  border: 1px solid var(--color-gray-200);
  border-radius: var(--radius-sm);
  margin-bottom: 12px;
  transition: var(--transition);
}

.cert-badge:hover {
  box-shadow: var(--shadow-md);
  border-color: transparent;
}

.cert-badge__icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-sm);
  background: var(--color-gray-100);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-size: 1.2rem;
}

.cert-badge__text {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-gray-700);
}

.cert-badge__sub {
  font-size: 0.8rem;
  color: var(--color-text-light);
}


/* ------------------------------------------------------------
   11. Contact Section
   ------------------------------------------------------------ */
.contact__layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: start;
}

/* Info */
.contact__info-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-navy);
  margin-bottom: 24px;
}

.contact__info-item {
  display: flex;
  gap: 16px;
  margin-bottom: 20px;
}

.contact__info-icon {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-gray-100);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  color: var(--color-teal);
}

.contact__info-label {
  font-size: 0.8rem;
  color: var(--color-text-light);
  margin-bottom: 2px;
}

.contact__info-value {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--color-gray-700);
}

.contact__map {
  width: 100%;
  height: 200px;
  background: var(--color-gray-100);
  border-radius: var(--radius-md);
  margin-top: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-light);
  font-size: 0.9rem;
  overflow: hidden;
}

.contact__map iframe {
  width: 100%;
  height: 100%;
  border: 0;
}

/* Form */
.contact__form {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.form-group__label {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--color-gray-700);
}

.form-group__input,
.form-group__textarea {
  width: 100%;
  padding: 14px 18px;
  font-size: 0.95rem;
  border: 1px solid var(--color-gray-300);
  border-radius: var(--radius-sm);
  background: var(--color-white);
  color: var(--color-text);
  transition: var(--transition);
  outline: none;
}

.form-group__input:focus,
.form-group__textarea:focus {
  border-color: var(--color-teal);
  box-shadow: 0 0 0 3px rgba(13, 155, 122, 0.12);
}

.form-group__input::placeholder,
.form-group__textarea::placeholder {
  color: var(--color-gray-400);
}

.form-group__textarea {
  min-height: 140px;
  resize: vertical;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.btn--submit {
  width: 100%;
  padding: 16px;
  font-size: 1rem;
  font-weight: 600;
  background: var(--color-teal);
  color: var(--color-white);
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: var(--transition);
}

.btn--submit:hover {
  background: var(--color-teal-dark);
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(13, 155, 122, 0.3);
}


/* ------------------------------------------------------------
   12. Modal
   ------------------------------------------------------------ */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  z-index: 2000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
}

.modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

.modal {
  background: var(--color-white);
  border-radius: var(--radius-lg);
  max-width: 900px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  position: relative;
  transform: scale(0.95) translateY(20px);
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.modal-overlay.active .modal {
  transform: scale(1) translateY(0);
}

.modal__close {
  position: absolute;
  top: 20px;
  right: 20px;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--color-gray-100);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  color: var(--color-gray-600);
  cursor: pointer;
  transition: var(--transition);
  z-index: 1;
  border: none;
}

.modal__close:hover {
  background: var(--color-gray-200);
  color: var(--color-gray-800);
}

.modal__image {
  width: 100%;
  aspect-ratio: 16 / 10;
  background: var(--color-gray-100);
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-lg) var(--radius-lg) 0 0;
  overflow: hidden;
}

.modal__image img {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
}

.modal__body {
  padding: 40px;
}

.modal__category {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--color-teal);
  margin-bottom: 8px;
}

.modal__title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-navy);
  margin-bottom: 16px;
}

.modal__desc {
  font-size: 0.95rem;
  color: var(--color-gray-600);
  line-height: 1.8;
  margin-bottom: 32px;
}

.modal__specs {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.modal__spec-item {
  padding: 16px;
  background: var(--color-gray-50);
  border-radius: var(--radius-sm);
}

.modal__spec-label {
  font-size: 0.8rem;
  color: var(--color-text-light);
  margin-bottom: 4px;
}

.modal__spec-value {
  font-size: 1rem;
  font-weight: 600;
  color: var(--color-navy);
}

/* Spec Table (built by JS) */
.modal__spec-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 16px;
}

.modal__spec-body th,
.modal__spec-body td {
  padding: 12px 16px;
  font-size: 0.9rem;
  border-bottom: 1px solid var(--color-gray-200);
  text-align: left;
}

.modal__spec-body th {
  font-weight: 600;
  color: var(--color-gray-600);
  width: 35%;
  background: var(--color-gray-50);
}

.modal__spec-body td {
  color: var(--color-navy);
  font-weight: 500;
}

/* Modal Features List */
.modal__features {
  margin-top: 32px;
}

.modal__features h4 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-navy);
  margin-bottom: 12px;
}

.modal__features ul {
  list-style: none;
  padding: 0;
}

.modal__features li {
  padding: 6px 0;
  font-size: 0.9rem;
  color: var(--color-gray-600);
  padding-left: 20px;
  position: relative;
}

.modal__features li::before {
  content: '\2713';
  position: absolute;
  left: 0;
  color: var(--color-teal);
  font-weight: 700;
}


/* ------------------------------------------------------------
   13. Footer
   ------------------------------------------------------------ */
.footer {
  background: var(--color-navy);
  color: rgba(255, 255, 255, 0.6);
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  padding: 60px 0 40px;
}

.footer__inner {
  display: flex;
  align-items: start;
  justify-content: space-between;
  gap: 40px;
  flex-wrap: wrap;
}

.footer__logo {
  font-family: var(--font-en);
  font-size: 1.3rem;
  font-weight: 800;
  letter-spacing: 3px;
  color: var(--color-white);
  margin-bottom: 12px;
}

.footer__desc {
  font-size: 0.85rem;
  line-height: 1.7;
  max-width: 300px;
}

.footer__nav {
  display: flex;
  gap: 32px;
}

.footer__nav-link {
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.5);
  transition: var(--transition);
}

.footer__nav-link:hover {
  color: var(--color-white);
}

.footer__bottom {
  margin-top: 40px;
  padding-top: 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  text-align: center;
  font-size: 0.8rem;
}


/* ------------------------------------------------------------
   13b. Page Hero (subpages)
   ------------------------------------------------------------ */
.page-hero {
  background: var(--color-navy);
  padding-top: calc(var(--header-height) + 60px);
  padding-bottom: 60px;
  text-align: center;
  min-height: 300px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.page-hero__content {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 24px;
}

.page-hero__label {
  font-family: var(--font-en);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--color-teal-light);
  margin-bottom: 16px;
  display: block;
}

.page-hero__title {
  font-family: var(--font-kr);
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 700;
  color: var(--color-white);
  line-height: 1.3;
}

/* Controller card modifier */
.product-card--controller .product-card__badge {
  background: var(--color-navy);
}


/* ------------------------------------------------------------
   14. Responsive: Tablet (768px - 1024px)
   ------------------------------------------------------------ */
@media (max-width: 1024px) {
  .section {
    padding: 100px 0;
  }

  .about__grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
  }

  .about__card {
    padding: 36px 24px;
  }

  .tech__benefits {
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
  }

  .history__layout {
    grid-template-columns: 1fr;
    gap: 48px;
  }

  .contact__layout {
    grid-template-columns: 1fr;
    gap: 48px;
  }

  .products__grid {
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  }
}


/* ------------------------------------------------------------
   15. Responsive: Mobile (< 768px)
   ------------------------------------------------------------ */
@media (max-width: 767px) {
  .section {
    padding: 80px 0;
  }

  .section__header {
    margin-bottom: 40px;
  }

  .container {
    padding: 0 20px;
  }

  /* Header Mobile */
  .header__nav {
    display: none;
  }

  .header__hamburger {
    display: flex;
  }

  /* Hero Mobile */
  .hero__content {
    padding: 0 20px;
  }

  .hero__cta {
    flex-direction: column;
    gap: 12px;
  }

  .btn {
    padding: 12px 32px;
    font-size: 0.9rem;
    width: 100%;
    max-width: 280px;
  }

  .hero__scroll {
    bottom: 24px;
  }

  /* About Mobile */
  .about__grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .about__card {
    padding: 32px 24px;
  }

  /* Products Mobile */
  .products__filter {
    justify-content: flex-start;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    padding-bottom: 4px;
    flex-wrap: nowrap;
  }

  .products__filter::-webkit-scrollbar {
    display: none;
  }

  .products__grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  /* Tech Mobile */
  .tech__benefits {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  /* History Mobile */
  .history__layout {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  /* Contact Mobile */
  .contact__layout {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .form-row {
    grid-template-columns: 1fr;
  }

  /* Modal Mobile */
  .modal-overlay {
    padding: 0;
    align-items: flex-end;
  }

  .modal {
    max-height: 95vh;
    border-radius: var(--radius-lg) var(--radius-lg) 0 0;
    max-width: 100%;
  }

  .modal__body {
    padding: 24px;
  }

  .modal__specs {
    grid-template-columns: 1fr;
  }

  .modal__image {
    border-radius: var(--radius-lg) var(--radius-lg) 0 0;
  }

  /* Footer Mobile */
  .footer__inner {
    flex-direction: column;
    text-align: center;
    gap: 24px;
  }

  .footer__desc {
    max-width: 100%;
  }

  .footer__nav {
    justify-content: center;
    flex-wrap: wrap;
    gap: 20px;
  }
}


/* ------------------------------------------------------------
   16. Scrollbar Styling
   ------------------------------------------------------------ */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--color-gray-100);
}

::-webkit-scrollbar-thumb {
  background: var(--color-gray-300);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-gray-400);
}


/* ------------------------------------------------------------
   17. Selection & Focus Styles
   ------------------------------------------------------------ */
::selection {
  background: rgba(13, 155, 122, 0.2);
  color: var(--color-navy);
}

:focus-visible {
  outline: 2px solid var(--color-teal);
  outline-offset: 2px;
}


/* ------------------------------------------------------------
   18. Page Hero Banner (for subpages)
   ------------------------------------------------------------ */
.page-hero {
  background: linear-gradient(135deg, var(--color-navy) 0%, var(--color-navy-light) 100%);
  padding: 140px 0 80px;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.page-hero::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background: radial-gradient(ellipse at 30% 50%, rgba(13,155,122,0.15) 0%, transparent 60%);
}
.page-hero__label {
  font-family: var(--font-en);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--color-teal-light);
  margin-bottom: 12px;
  position: relative;
}
.page-hero__title {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 700;
  color: var(--color-white);
  position: relative;
}


/* ------------------------------------------------------------
   19. Controller-specific Product Card
   ------------------------------------------------------------ */
/* Controller card - no spec preview, shows model list instead */
.product-card--controller .product-card__spec {
  font-size: 13px;
  color: var(--color-gray-500);
  line-height: 1.6;
}
.product-card--controller .product-card__image img {
  object-fit: contain;
  padding: 16px;
  background: linear-gradient(135deg, #f0fdf9 0%, #f8f9fa 100%);
}


/* ------------------------------------------------------------
   20. Controller Modal (special layout for non-ventilation products)
   ------------------------------------------------------------ */
.modal--controller .modal__spec-table { display: none; }
.modal--controller .modal__desc {
  font-size: 15px;
  line-height: 1.8;
  color: var(--color-gray-600);
  margin-bottom: 24px;
  padding: 20px;
  background: var(--color-gray-50);
  border-radius: var(--radius-md);
  border-left: 4px solid var(--color-teal);
}
.modal--controller .modal__models {
  font-size: 14px;
  color: var(--color-gray-500);
  margin-bottom: 20px;
  font-family: var(--font-en);
  letter-spacing: 0.5px;
}
.modal--controller .modal__features {
  display: block;
}
.modal--controller .modal__features ul {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px 16px;
}
@media (max-width: 768px) {
  .modal--controller .modal__features ul {
    grid-template-columns: 1fr;
  }
}


/* ------------------------------------------------------------
   21. Hero Enhancement - More dramatic
   ------------------------------------------------------------ */
/* Floating leaf elements */
.hero__leaf {
  position: absolute;
  width: var(--leaf-size, 20px);
  height: var(--leaf-size, 20px);
  border-radius: 50% 0 50% 0;
  background: rgba(13,155,122, var(--leaf-opacity, 0.15));
  z-index: 3;
  pointer-events: none;
}
/* SVG airflow decorative lines */
.hero__airflow {
  position: absolute;
  z-index: 3;
  pointer-events: none;
  opacity: 0.15;
}
/* Hero stats counter bar */
.hero__stats {
  display: flex;
  justify-content: center;
  gap: 60px;
  margin-top: 48px;
  position: relative;
  z-index: 10;
}
.hero__stat {
  text-align: center;
  color: var(--color-white);
}
.hero__stat-value {
  font-family: var(--font-en);
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 800;
  color: var(--color-teal-light);
  line-height: 1;
}
.hero__stat-label {
  font-size: 14px;
  opacity: 0.7;
  margin-top: 8px;
}
@media (max-width: 768px) {
  .hero__stats { gap: 30px; flex-wrap: wrap; }
  .hero__stat-value { font-size: 1.8rem; }
}


/* ------------------------------------------------------------
   22. CTA Banner Section
   ------------------------------------------------------------ */
.cta-banner {
  background: linear-gradient(135deg, var(--color-navy) 0%, #0f2b4a 50%, var(--color-navy-light) 100%);
  padding: 100px 0;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.cta-banner::before {
  content: '';
  position: absolute;
  top: -50%; left: -50%;
  width: 200%; height: 200%;
  background: radial-gradient(ellipse at center, rgba(13,155,122,0.1) 0%, transparent 50%);
  animation: cta-glow 8s ease-in-out infinite;
}
@keyframes cta-glow {
  0%, 100% { transform: translate(0, 0); }
  50% { transform: translate(5%, 5%); }
}
.cta-banner__title {
  font-size: clamp(1.5rem, 3.5vw, 2.5rem);
  font-weight: 700;
  color: var(--color-white);
  margin-bottom: 16px;
  position: relative;
}
.cta-banner__sub {
  font-size: 16px;
  color: rgba(255,255,255,0.7);
  margin-bottom: 32px;
  position: relative;
}


/* ------------------------------------------------------------
   23. "View All" Button Style
   ------------------------------------------------------------ */
.products__view-all {
  text-align: center;
  margin-top: 48px;
}
.products__view-all a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 16px;
  font-weight: 600;
  color: var(--color-teal);
  padding: 14px 32px;
  border: 2px solid var(--color-teal);
  border-radius: 50px;
  transition: var(--transition);
}
.products__view-all a:hover {
  background: var(--color-teal);
  color: var(--color-white);
}


/* ------------------------------------------------------------
   24. Comprehensive Mobile Overrides
   ------------------------------------------------------------ */

/* Mobile detection helper - shown/hidden classes */
.desktop-only { display: block; }
.mobile-only { display: none; }

@media (max-width: 767px) {
  .desktop-only { display: none !important; }
  .mobile-only { display: block !important; }

  /* Page Hero - compact on mobile */
  .page-hero {
    padding: 100px 0 50px;
  }
  .page-hero__title {
    font-size: 1.8rem;
  }
  .page-hero__label {
    font-size: 12px;
    letter-spacing: 2px;
  }

  /* Hero section mobile */
  .hero__title {
    font-size: clamp(1.6rem, 6vw, 2.4rem) !important;
    line-height: 1.3;
  }
  .hero__title-kr {
    font-size: clamp(0.85rem, 3.5vw, 1.1rem);
    margin-top: 8px;
  }
  .hero__subtitle {
    font-size: 0.85rem;
    padding: 0 10px;
    line-height: 1.6;
  }
  .hero__stats {
    gap: 20px;
    margin-top: 32px;
    flex-wrap: nowrap;
  }
  .hero__stat-value {
    font-size: 1.5rem;
  }
  .hero__stat-label {
    font-size: 11px;
  }
  .hero__scroll-text {
    font-size: 10px;
  }

  /* Hide some hero decorations on mobile for performance */
  .hero__bg-trees,
  .hero__leaf,
  .hero__airflow,
  .hero__cloud {
    display: none;
  }
  .hero__particle:nth-child(n+10) {
    display: none;
  }

  /* Section titles mobile */
  .section__title {
    font-size: clamp(1.4rem, 5vw, 1.8rem);
  }
  .section__subtitle {
    font-size: 0.9rem;
    line-height: 1.6;
  }
  .section__label {
    font-size: 11px;
  }

  /* About cards mobile */
  .about__card {
    padding: 28px 20px;
  }
  .about__icon {
    width: 52px;
    height: 52px;
  }
  .about__card-title {
    font-size: 1.05rem;
  }
  .about__card-desc {
    font-size: 0.85rem;
  }

  /* Product cards mobile - 2 columns for small cards */
  .products__grid {
    grid-template-columns: repeat(2, 1fr) !important;
    gap: 12px;
  }
  .product-card__name {
    font-size: 0.85rem;
  }
  .product-card__spec {
    font-size: 0.75rem;
  }
  .product-card__badge {
    font-size: 10px;
    padding: 3px 8px;
  }
  .product-card__more {
    font-size: 0.8rem;
    padding: 8px 16px;
  }

  /* Filter tabs - horizontal scroll with gradient hint */
  .products__filter {
    gap: 6px;
    padding: 0 0 8px;
    margin-bottom: 20px;
    position: relative;
  }
  .products__filter-btn {
    font-size: 12px;
    padding: 8px 14px;
    white-space: nowrap;
    flex-shrink: 0;
  }

  /* Technology diagram - hide horizontal, show vertical */
  .tech__diagram svg {
    width: 100%;
    height: auto;
  }
  .tech__card {
    padding: 20px 16px;
  }
  .tech__card-value {
    font-size: 1.8rem;
  }
  .tech__card-label {
    font-size: 0.8rem;
  }

  /* Timeline mobile */
  .timeline__item {
    padding-left: 24px;
  }
  .timeline__year {
    font-size: 0.8rem;
  }
  .timeline__text {
    font-size: 0.85rem;
  }

  /* Cert badges mobile */
  .cert-badge {
    padding: 14px 16px;
  }
  .cert-badge__text {
    font-size: 0.9rem;
  }
  .cert-badge__sub {
    font-size: 0.75rem;
  }

  /* Contact mobile */
  .contact__info-title {
    font-size: 1.1rem;
  }
  .contact__info-value {
    font-size: 0.9rem;
  }

  /* CTA Banner mobile */
  .cta-banner {
    padding: 60px 20px;
  }
  .cta-banner__title {
    font-size: 1.3rem;
    line-height: 1.4;
  }
  .cta-banner__sub {
    font-size: 0.85rem;
  }

  /* View all button mobile */
  .products__view-all {
    margin-top: 32px;
  }
  .products__view-all a {
    font-size: 14px;
    padding: 12px 24px;
    width: 100%;
    max-width: 280px;
    justify-content: center;
  }

  /* Modal - bottom sheet style on mobile */
  .modal {
    width: 100%;
    max-width: 100%;
    border-radius: 16px 16px 0 0;
  }
  .modal__close {
    top: 12px;
    right: 12px;
    width: 32px;
    height: 32px;
    font-size: 16px;
  }
  .modal__title {
    font-size: 1.2rem;
  }
  .modal__image {
    max-height: 200px;
  }
  .modal__image img {
    max-height: 200px;
    object-fit: contain;
  }
  .modal__spec-table th,
  .modal__spec-table td {
    padding: 8px 10px;
    font-size: 0.8rem;
  }

  /* Footer mobile */
  .footer {
    padding: 40px 0 24px;
  }
  .footer__logo {
    font-size: 1.3rem;
  }
  .footer__desc {
    font-size: 0.8rem;
  }
  .footer__nav {
    gap: 16px;
  }
  .footer__nav-link {
    font-size: 0.8rem;
  }

  /* Mobile hamburger menu enhancement */
  .mobile-menu {
    padding-top: 80px;
  }
  .mobile-menu__link {
    font-size: 1.3rem;
    padding: 16px 0;
  }
}

/* Very small phones (< 380px) */
@media (max-width: 380px) {
  .products__grid {
    grid-template-columns: 1fr !important;
  }
  .hero__stats {
    flex-direction: column;
    gap: 16px;
    align-items: center;
  }
  .hero__stat {
    display: flex;
    align-items: center;
    gap: 12px;
  }
}

/* Tablet specific (768px - 1024px) */
@media (min-width: 768px) and (max-width: 1024px) {
  .products__grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .page-hero {
    padding: 120px 0 60px;
  }
  .hero__stats {
    gap: 40px;
  }
}