/* ============================================================================
   CSS SPRITES - Image Request Optimization
   ============================================================================
   Reduces HTTP requests from 44+ individual images to just 3 sprite sheets.
   Each sprite uses CSS custom property --icon-index for positioning.
   ============================================================================ */

/* Base sprite class */
.icon-sprite {
  display: inline-block;
  width: 50px;
  height: 50px;
  background-repeat: no-repeat;
  background-size: auto 50px;
  vertical-align: middle;
}

/* Company icons */
.icon-company {
  background-image: url('/static/images/sprites/sprite-companies.png');
  background-position-x: calc(var(--icon-index, 0) * -50px);
}

/* Project icons */
.icon-project {
  background-image: url('/static/images/sprites/sprite-projects.png');
  background-position-x: calc(var(--icon-index, 0) * -50px);
}

/* Course icons */
.icon-course {
  background-image: url('/static/images/sprites/sprite-courses.png');
  background-position-x: calc(var(--icon-index, 0) * -50px);
}

/* Retina displays - use @2x sprites for crisp rendering */
@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
  .icon-company {
    background-image: url('/static/images/sprites/sprite-companies@2x.png');
    background-size: auto 50px; /* Display at 1x size */
  }

  .icon-project {
    background-image: url('/static/images/sprites/sprite-projects@2x.png');
    background-size: auto 50px;
  }

  .icon-course {
    background-image: url('/static/images/sprites/sprite-courses@2x.png');
    background-size: auto 50px;
  }
}

/* Size variants for different contexts */
.icon-sprite.icon-small {
  width: 32px;
  height: 32px;
  background-size: auto 32px;
}

.icon-sprite.icon-small.icon-company {
  background-position-x: calc(var(--icon-index, 0) * -32px);
}

.icon-sprite.icon-small.icon-project {
  background-position-x: calc(var(--icon-index, 0) * -32px);
}

.icon-sprite.icon-small.icon-course {
  background-position-x: calc(var(--icon-index, 0) * -32px);
}

.icon-sprite.icon-large {
  width: 64px;
  height: 64px;
  background-size: auto 64px;
}

.icon-sprite.icon-large.icon-company {
  background-position-x: calc(var(--icon-index, 0) * -64px);
}

.icon-sprite.icon-large.icon-project {
  background-position-x: calc(var(--icon-index, 0) * -64px);
}

.icon-sprite.icon-large.icon-course {
  background-position-x: calc(var(--icon-index, 0) * -64px);
}

/* For section logos - match .company-logo img styling */
/* Use a wrapper approach: 80px box, 60px icon centered inside */
.icon-sprite.icon-section {
  /* Outer box matches img styling */
  width: 80px;
  height: 80px;
  border-radius: 4px;
  border: 1px solid var(--icon-border, #ddd);
  background-color: transparent;
  box-sizing: border-box;
  /* Inner content area for sprite */
  padding: 10px;
  background-size: auto 60px;
  background-origin: content-box;
  background-clip: content-box;
  background-position: 0 0;
}

.icon-sprite.icon-section.icon-company {
  background-position-x: calc(var(--icon-index, 0) * -60px);
}

.icon-sprite.icon-section.icon-project {
  background-position-x: calc(var(--icon-index, 0) * -60px);
}

.icon-sprite.icon-section.icon-course {
  background-position-x: calc(var(--icon-index, 0) * -60px);
}

/* Retina overrides for size variants */
@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
  .icon-sprite.icon-small {
    background-size: auto 32px;
  }

  .icon-sprite.icon-small.icon-company {
    background-position-x: calc(var(--icon-index, 0) * -32px);
  }

  .icon-sprite.icon-small.icon-project {
    background-position-x: calc(var(--icon-index, 0) * -32px);
  }

  .icon-sprite.icon-small.icon-course {
    background-position-x: calc(var(--icon-index, 0) * -32px);
  }

  .icon-sprite.icon-large {
    background-size: auto 64px;
  }

  .icon-sprite.icon-large.icon-company {
    background-position-x: calc(var(--icon-index, 0) * -64px);
  }

  .icon-sprite.icon-large.icon-project {
    background-position-x: calc(var(--icon-index, 0) * -64px);
  }

  .icon-sprite.icon-large.icon-course {
    background-position-x: calc(var(--icon-index, 0) * -64px);
  }

  .icon-sprite.icon-section {
    padding: 10px;
    background-size: auto 60px;
    background-position: 0 0;
  }

  .icon-sprite.icon-section.icon-company {
    background-size: auto 60px;
    background-position-x: calc(var(--icon-index, 0) * -60px);
  }

  .icon-sprite.icon-section.icon-project {
    background-size: auto 60px;
    background-position-x: calc(var(--icon-index, 0) * -60px);
  }

  .icon-sprite.icon-section.icon-course {
    background-size: auto 60px;
    background-position-x: calc(var(--icon-index, 0) * -60px);
  }
}