/* ============================================================
   CSS VARIABLES
   ============================================================ */
:root {
  /* Colors */
  --bg-primary: #0d1117;
  --bg-secondary: #161b22;
  --bg-tertiary: #0b121b;
  --bg-input: #010409;
  --text-primary: #e6edf3;
  --text-secondary: #8b949e;
  --text-muted: #c9d1d9;
  
  /* Accent Colors */
  --accent-primary: #14c2b8;
  --accent-primary-hover: #11a89f;
  --accent-secondary: #238636;
  --accent-secondary-hover: #2ea043;
  --accent-rating: #f0c674;
  --error: #f85149;
  
  /* Borders */
  --border-default: rgba(255, 255, 255, 0.06);
  --border-hover: rgba(0, 255, 200, 0.3);
  --border-input: rgba(255, 255, 255, 0.14);
  --border-focus: rgba(255, 255, 255, 0.08);
  
  /* Spacing */
  --spacing-xs: 8px;
  --spacing-sm: 12px;
  --spacing-md: 20px;
  --spacing-lg: 30px;
  --spacing-xl: 50px;
  
  /* Border Radius */
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 10px;
  --radius-xl: 12px;
  
  /* Transitions */
  --transition-fast: 0.2s ease;
}

/* ============================================================
   GLOBAL LAYOUT
   ============================================================ */
* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  padding: 0 20px;
  line-height: 1.6;
}

/* ============================================================
   NAVIGATION
   ============================================================ */
nav {
  max-width: 1100px;
  margin: 0 auto;
  padding: var(--spacing-md) 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

nav .logo {
  font-size: 20px;
  font-weight: 700;
  color: var(--text-primary);
}

nav .logo span {
  color: var(--accent-primary);
}

nav ul {
  list-style: none;
  display: flex;
  gap: var(--spacing-md);
  padding: 0;
  margin: 0;
}

nav a {
  text-decoration: none;
  color: var(--text-primary);
  opacity: 0.8;
  font-weight: 500;
  transition: var(--transition-fast);
}

nav a:hover,
nav a.active {
  opacity: 1;
  color: var(--accent-primary);
}

/* ============================================================
   HEADER
   ============================================================ */
.page-header {
  text-align: center;
  padding: var(--spacing-xl) 0 var(--spacing-lg);
}

.page-header h1 {
  font-size: 36px;
  margin: 0 0 10px;
  font-weight: 700;
}

.page-header p {
  opacity: 0.7;
  font-size: 16px;
  margin: 0;
}

/* ============================================================
   CONTAINER
   ============================================================ */
.container {
  max-width: 1100px;
  margin: 0 auto 60px;
}

/* ============================================================
   PRODUCT GRID
   ============================================================ */
.products-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  grid-gap: 24px;
  max-width: 1000px;
  margin: 0 auto 60px;
}

/* ============================================================
   PRODUCT CARD
   ============================================================ */
.product-card {
  background: var(--bg-secondary);
  padding: 22px;
  border-radius: var(--radius-xl);
  border: 1px solid var(--border-default);
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  transition: var(--transition-fast);
}

.product-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-4px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.product-card h2 {
  margin: 10px 0 var(--spacing-xs);
  font-size: 20px;
  font-weight: 600;
}

.product-card p {
  font-size: 15px;
  opacity: 0.75;
  margin-bottom: 15px;
  flex-grow: 1;
}

.product-card.full-width {
  grid-column: 1 / -1;
  text-align: center;
  align-items: center;
  position: relative;
}

.product-icon-big {
  width: 70px;
  height: 70px;
  margin-bottom: var(--spacing-sm);
  opacity: 0.95;
}

.product-icon {
  width: 42px;
  height: 42px;
  margin-bottom: var(--spacing-sm);
  border-radius: var(--radius-md);
  object-fit: cover;
  opacity: 0.9;
}

.lines {
  font-size: 14px;
  margin-bottom: var(--spacing-xs);
  opacity: 0.8;
}

.price {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 15px;
  color: var(--text-primary);
}

.price.discounted {
  color: var(--accent-primary);
}

/* ============================================================
   BADGE
   ============================================================ */
.badge {
  background: var(--accent-primary);
  color: var(--bg-primary);
  padding: 5px var(--spacing-sm);
  border-radius: var(--radius-sm);
  font-size: 13px;
  margin-bottom: 15px;
  font-weight: 700;
  display: inline-block;
}

/* ============================================================
   BUTTONS
   ============================================================ */
.btn {
  width: 100%;
  padding: var(--spacing-sm);
  background: var(--accent-secondary);
  border: none;
  color: white;
  font-weight: 700;
  font-size: 15px;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: var(--transition-fast);
  font-family: inherit;
}

.btn:hover {
  background: var(--accent-secondary-hover);
  transform: translateY(-1px);
}

.btn:active {
  transform: translateY(0);
}

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

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

.btn-outline {
  width: 100%;
  padding: var(--spacing-sm);
  background: transparent;
  border: 1px solid var(--accent-primary);
  color: var(--accent-primary);
  font-weight: 600;
  font-size: 15px;
  border-radius: var(--radius-md);
  cursor: pointer;
  margin-top: 10px;
  transition: var(--transition-fast);
}

.btn-outline:hover {
  background: rgba(20, 194, 184, 0.15);
}

/* ============================================================
   PRODUCT DETAIL PAGE
   ============================================================ */
.product-detail {
  margin-top: var(--spacing-lg);
}

.product-main {
  display: grid;
  grid-template-columns: 1fr 1.3fr;
  gap: var(--spacing-lg);
  align-items: center;
  margin-bottom: var(--spacing-xl);
}

.product-detail-img {
  width: 100%;
  max-width: 280px;
  margin: 0 auto;
  border-radius: var(--radius-lg);
}

.product-info h1 {
  font-size: 32px;
  margin-top: 0;
  font-weight: 700;
}

.product-tagline {
  opacity: 0.75;
  margin-bottom: var(--spacing-md);
  font-size: 16px;
}

.product-price {
  font-size: 28px;
  font-weight: 700;
  color: var(--accent-primary);
  margin-bottom: 16px;
}

.price-note {
  font-size: 14px;
  color: var(--text-secondary);
  margin-left: var(--spacing-xs);
  font-weight: 400;
}

.product-features {
  padding-left: 18px;
  margin-bottom: var(--spacing-md);
  list-style: disc;
}

.product-features li {
  margin-bottom: var(--spacing-xs);
  opacity: 0.9;
  line-height: 1.6;
}

/* ============================================================
   USE CASES SECTION
   ============================================================ */
.use-cases {
  margin-bottom: 60px;
  padding: var(--spacing-lg);
  background: var(--bg-secondary);
  border-radius: var(--radius-xl);
  border: 1px solid var(--border-default);
}

.use-cases h2 {
  margin-top: 0;
  margin-bottom: var(--spacing-md);
  font-size: 24px;
}

.use-cases ul {
  list-style: none;
  padding-left: 0;
}

.use-cases li {
  padding: var(--spacing-xs) 0;
  padding-left: 24px;
  position: relative;
  opacity: 0.9;
}

.use-cases li::before {
  content: "→";
  position: absolute;
  left: 0;
  color: var(--accent-primary);
}

/* ============================================================
   SAMPLE PREVIEW
   ============================================================ */
.sample-preview {
  margin-bottom: 60px;
}

.sample-preview h2 {
  margin-bottom: var(--spacing-sm);
}

.code-box {
  background: var(--bg-input);
  border: 1px solid var(--border-focus);
  padding: 15px;
  border-radius: var(--radius-lg);
  font-size: 13px;
  overflow-x: auto;
  max-height: 220px;
  color: var(--text-muted);
  font-family: "Courier New", monospace;
}

/* ============================================================
   PURCHASE FORM
   ============================================================ */
.purchase-form {
  width: 100%;
  max-width: 420px;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.purchase-form input,
.purchase-form select {
  width: 100%;
  height: 48px;
  padding: 0 14px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-input);
  background: var(--bg-input);
  color: var(--text-primary);
  font-size: 15px;
  font-family: inherit;
  transition: var(--transition-fast);
}

.purchase-form select {
  appearance: none;
  cursor: pointer;
  background-image:
    linear-gradient(45deg, transparent 50%, var(--text-secondary) 50%),
    linear-gradient(135deg, var(--text-secondary) 50%, transparent 50%);
  background-position:
    calc(100% - 20px) 20px,
    calc(100% - 15px) 20px;
  background-size: 5px 5px, 5px 5px;
  background-repeat: no-repeat;
}

.purchase-form input:focus,
.purchase-form select:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 2px rgba(20, 194, 184, 0.15);
}

.purchase-form button {
  height: 50px;
  border-radius: var(--radius-lg);
  font-size: 16px;
  font-weight: 700;
  margin-top: var(--spacing-xs);
}

/* ============================================================
   FEEDBACK SECTION
   ============================================================ */
.feedback {
  margin-top: var(--spacing-xl);
}

.feedback h2 {
  margin-bottom: var(--spacing-md);
  font-size: 24px;
}

.feedback-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-default);
  padding: 15px;
  border-radius: var(--radius-lg);
  margin-bottom: 15px;
  transition: var(--transition-fast);
}

.feedback-card:hover {
  border-color: var(--border-input);
}

.fb-header {
  margin-bottom: 6px;
  font-size: 14px;
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.fb-rating {
  color: var(--accent-rating);
}

.fb-text {
  opacity: 0.85;
  font-size: 15px;
  margin: 0;
  line-height: 1.5;
}

/* ============================================================
   LEAVE FEEDBACK FORM
   ============================================================ */
.leave-feedback {
  margin-top: var(--spacing-lg);
  background: var(--bg-tertiary);
  border: 1px solid var(--border-focus);
  padding: var(--spacing-md);
  border-radius: var(--radius-xl);
}

.leave-feedback h3 {
  margin-top: 0;
  margin-bottom: 15px;
  font-size: 20px;
}

.leave-feedback input,
.leave-feedback textarea,
.leave-feedback select {
  width: 100%;
  margin-bottom: var(--spacing-sm);
  padding: 10px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-input);
  background: var(--bg-input);
  color: var(--text-primary);
  font-family: inherit;
  transition: var(--transition-fast);
}

.leave-feedback input::placeholder,
.leave-feedback textarea::placeholder {
  color: var(--text-secondary);
}

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

.feedback-form input,
.feedback-form select,
.feedback-form textarea {
  width: 100%;
  height: 48px;
  padding: 0 14px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-input);
  background: var(--bg-input);
  color: var(--text-primary);
  font-size: 15px;
  font-family: inherit;
  transition: var(--transition-fast);
}

.feedback-form textarea {
  height: auto;
  min-height: 90px;
  padding: 12px 14px;
  resize: vertical;
}

.feedback-form select {
  appearance: none;
  cursor: pointer;
  background-image:
    linear-gradient(45deg, transparent 50%, var(--text-secondary) 50%),
    linear-gradient(135deg, var(--text-secondary) 50%, transparent 50%);
  background-position:
    calc(100% - 20px) 20px,
    calc(100% - 15px) 20px;
  background-size: 5px 5px, 5px 5px;
  background-repeat: no-repeat;
}

.feedback-form input:focus,
.feedback-form select:focus,
.feedback-form textarea:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 2px rgba(20, 194, 184, 0.15);
}

/* ============================================================
   FEEDBACK STATUS MESSAGES
   ============================================================ */
.feedback-success,
.feedback-error {
  display: none;
  padding: var(--spacing-sm);
  border-radius: var(--radius-lg);
  font-size: 14px;
  margin-bottom: 15px;
  font-weight: 500;
}

.feedback-success {
  background: rgba(20, 194, 184, 0.15);
  border: 1px solid rgba(20, 194, 184, 0.4);
  color: var(--accent-primary);
}

.feedback-error {
  background: rgba(248, 81, 73, 0.15);
  border: 1px solid rgba(248, 81, 73, 0.4);
  color: var(--error);
}

/* ============================================================
   FOOTER
   ============================================================ */
.footer {
  margin-top: 60px;
  padding: var(--spacing-lg) 0;
  border-top: 1px solid var(--border-default);
  text-align: center;
}

.footer-content {
  max-width: 1100px;
  margin: 0 auto;
}

.footer-content p {
  margin: 0;
  opacity: 0.7;
  font-size: 14px;
}

/* ============================================================
   RESPONSIVE DESIGN
   ============================================================ */
@media (max-width: 800px) {
  .product-main {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .product-features {
    text-align: left;
  }

  nav ul {
    gap: var(--spacing-sm);
  }

  .page-header h1 {
    font-size: 28px;
  }

  .product-info h1 {
    font-size: 24px;
  }

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

@media (max-width: 600px) {
  body {
    padding: 0 15px;
  }

  .page-header {
    padding: var(--spacing-lg) 0 var(--spacing-md);
  }

  .page-header h1 {
    font-size: 24px;
  }

  nav {
    flex-direction: column;
    gap: var(--spacing-sm);
  }

  nav ul {
    flex-wrap: wrap;
    justify-content: center;
  }
}