/* ===========================
   Variables & Reset
   =========================== */
:root {
  --color-primary: rgb(255, 87, 34); /* #ff5722 */
  --color-primary-dark: rgb(230, 74, 25); /* #e64a19 */
  --color-white: #ffffff;
  --color-gray-light: #f8f9fa;
  --color-gray: #6c757d;
  --color-gray-dark: #343a40;
  --color-black: #212529;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Yu Gothic", YuGothic, sans-serif;

  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 2rem;
  --spacing-lg: 3rem;
  --spacing-xl: 4rem;

  --border-radius: 8px;
  --transition: all 0.3s ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  line-height: 1.6;
  color: var(--color-black);
  background-color: var(--color-white);
}

/* ===========================
   Typography
   =========================== */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: var(--spacing-sm);
}

h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
}

h2 {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
}

h3 {
  font-size: clamp(1.5rem, 3vw, 2rem);
}

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

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

a:hover {
  color: var(--color-primary-dark);
}

/* ===========================
   Layout
   =========================== */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

.container-narrow {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

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

/* ===========================
   Header / Navigation
   =========================== */
header {
  background-color: var(--color-white);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  position: sticky;
  top: 0;
  z-index: 1000;
}

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-sm) 0;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-black);
}

.logo img {
  width: 40px;
  height: 40px;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: var(--spacing-md);
}

.nav-links a {
  color: var(--color-black);
  font-weight: 500;
  padding: 0.5rem 1rem;
  border-radius: var(--border-radius);
  transition: var(--transition);
}

.nav-links a:hover {
  background-color: var(--color-gray-light);
  color: var(--color-primary);
}

/* Mobile Menu */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--color-black);
}

@media (max-width: 768px) {
  .menu-toggle {
    display: block;
  }

  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: var(--color-white);
    flex-direction: column;
    gap: 0;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
  }

  .nav-links.active {
    max-height: 500px;
  }

  .nav-links li {
    border-bottom: 1px solid var(--color-gray-light);
  }

  .nav-links a {
    display: block;
    padding: var(--spacing-sm) var(--spacing-md);
  }
}

/* ===========================
   Hero Section
   =========================== */
.hero {
  background:
    linear-gradient(135deg, rgba(255, 255, 255, 0.95) 0%, rgba(255, 255, 255, 0.85) 100%),
    url('../images/hero-background.jpg') center/cover no-repeat;
  padding: var(--spacing-xl) 0;
  text-align: center;
  position: relative;
}

.hero-content {
  max-width: 1000px;
  margin: 0 auto;
}

.hero h1 {
  color: var(--color-black);
  margin-bottom: var(--spacing-md);
}

.hero-subtitle {
  font-size: clamp(1.1rem, 2.5vw, 1.3rem);
  color: var(--color-gray);
  margin-bottom: var(--spacing-lg);
  line-height: 1.8;
}

.cta-buttons {
  display: flex;
  gap: var(--spacing-sm);
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: var(--spacing-lg);
}

.btn {
  display: inline-block;
  padding: 1rem 2rem;
  border-radius: var(--border-radius);
  font-weight: 600;
  font-size: 1.1rem;
  text-align: center;
  cursor: pointer;
  border: 2px solid transparent;
  transition: var(--transition);
}

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

.btn-primary:hover {
  background-color: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  color: var(--color-white);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(255, 87, 34, 0.3);
}

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

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

/* ===========================
   Features Section
   =========================== */
.features {
  background-color: var(--color-white);
}

.features h2 {
  text-align: center;
  margin-bottom: var(--spacing-lg);
  color: var(--color-black);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-md);
}

.feature-item {
  padding: var(--spacing-md);
  border-radius: var(--border-radius);
  background-color: var(--color-gray-light);
  transition: var(--transition);
}

.feature-item:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
}

.feature-item h3 {
  color: var(--color-primary);
  margin-bottom: var(--spacing-sm);
  font-size: 1.3rem;
}

.feature-item p {
  color: var(--color-gray-dark);
  margin-bottom: 0;
}

/* ===========================
   How to Use Section
   =========================== */
.how-to-use {
  background-color: var(--color-gray-light);
}

.how-to-use h2 {
  text-align: center;
  margin-bottom: var(--spacing-lg);
}

.steps {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
  max-width: 600px;
  margin: 0 auto;
}

.step {
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-sm);
  padding: var(--spacing-md);
  background-color: var(--color-white);
  border-radius: var(--border-radius);
  border-left: 4px solid var(--color-primary);
}

.step-number {
  flex-shrink: 0;
  width: 40px;
  height: 40px;
  background-color: var(--color-primary);
  color: var(--color-white);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1.2rem;
}

.step-content h3 {
  font-size: 1.2rem;
  margin-bottom: 0.5rem;
}

.step-content p {
  margin-bottom: 0;
  color: var(--color-gray-dark);
}

/* ===========================
   Gallery Section
   =========================== */
.gallery {
  background-color: var(--color-white);
}

.gallery h2 {
  text-align: center;
  margin-bottom: var(--spacing-lg);
}

.gallery-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--spacing-md);
}

.gallery-item {
  border-radius: var(--border-radius);
  overflow: hidden;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  transition: var(--transition);
}

.gallery-item:hover {
  transform: scale(1.05);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
}

.gallery-item img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  display: block;
}

.gallery-item-info {
  padding: var(--spacing-sm);
  background-color: var(--color-gray-light);
}

.gallery-item-info h4 {
  font-size: 1rem;
  margin-bottom: 0.25rem;
}

/* ===========================
   Download Section
   =========================== */
.download {
  background: linear-gradient(135deg, rgba(255, 87, 34, 0.05) 0%, rgba(255, 255, 255, 1) 100%);
}

.download h2 {
  text-align: center;
  margin-bottom: var(--spacing-lg);
}

.download-card {
  background-color: var(--color-white);
  padding: var(--spacing-lg);
  border-radius: var(--border-radius);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  margin-bottom: var(--spacing-md);
  text-align: center;
}

.download-card h3 {
  color: var(--color-primary);
  margin-bottom: var(--spacing-sm);
}

.version-badge {
  display: inline-block;
  background-color: var(--color-primary);
  color: var(--color-white);
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
}

.download-instructions {
  text-align: left;
  margin: var(--spacing-md) 0;
}

.download-instructions ol {
  padding-left: var(--spacing-md);
}

.download-instructions li {
  margin-bottom: 0.5rem;
  color: var(--color-gray-dark);
}

/* ===========================
   FAQ Section
   =========================== */
.faq {
  background-color: var(--color-gray-light);
}

.faq h2 {
  text-align: center;
  margin-bottom: var(--spacing-lg);
}

.faq-list {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  background-color: var(--color-white);
  margin-bottom: var(--spacing-sm);
  border-radius: var(--border-radius);
  overflow: hidden;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.05);
}

.faq-question {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  background-color: var(--color-white);
  border: none;
  text-align: left;
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-black);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: var(--transition);
}

.faq-question:hover {
  background-color: var(--color-gray-light);
}

.faq-question::after {
  content: '+';
  font-size: 1.5rem;
  color: var(--color-primary);
  transition: transform 0.3s ease;
}

.faq-question.active::after {
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease, padding 0.3s ease;
  padding: 0 var(--spacing-md);
}

.faq-answer.active {
  max-height: 500px;
  padding: var(--spacing-sm) var(--spacing-md) var(--spacing-md);
}

.faq-answer p {
  color: var(--color-gray-dark);
  margin-bottom: 0;
}

/* ===========================
   Footer
   =========================== */
footer {
  background-color: var(--color-gray-dark);
  color: var(--color-white);
  padding: var(--spacing-lg) 0 var(--spacing-md);
}

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

.footer-section h3 {
  color: var(--color-white);
  margin-bottom: var(--spacing-sm);
  font-size: 1.2rem;
}

.footer-section ul {
  list-style: none;
}

.footer-section ul li {
  margin-bottom: 0.5rem;
}

.footer-section a {
  color: var(--color-gray-light);
  transition: var(--transition);
}

.footer-section a:hover {
  color: var(--color-white);
  text-decoration: underline;
}

.footer-bottom {
  text-align: center;
  padding-top: var(--spacing-sm);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--color-gray);
}

/* ===========================
   Utility Classes
   =========================== */
.text-center {
  text-align: center;
}

.mb-1 {
  margin-bottom: var(--spacing-sm);
}

.mb-2 {
  margin-bottom: var(--spacing-md);
}

.mb-3 {
  margin-bottom: var(--spacing-lg);
}

.mt-1 {
  margin-top: var(--spacing-sm);
}

.mt-2 {
  margin-top: var(--spacing-md);
}

.mt-3 {
  margin-top: var(--spacing-lg);
}