/* ============================================
   SVG Icon System Utilities
   ============================================ */

/* Base icon styles - applies to all <svg> using sprite */
.icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1em;
  height: 1em;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
  vertical-align: middle;
  flex-shrink: 0;
}

/* Filled icons (social icons like QQ, WeChat) */
.icon--filled {
  fill: currentColor;
  stroke: none;
}

/* Size variants */
.icon--xs { width: 12px; height: 12px; }
.icon--sm { width: 14px; height: 14px; }
.icon--md { width: 16px; height: 16px; }
.icon--base { width: 20px; height: 20px; }
.icon--lg { width: 24px; height: 24px; }
.icon--xl { width: 32px; height: 32px; }
.icon--2xl { width: 40px; height: 40px; }
.icon--3xl { width: 48px; height: 48px; }
.icon--4xl { width: 64px; height: 64px; }

/* Thin stroke (for decorative/background icons) */
.icon--thin { stroke-width: 1; }

/* Thick stroke */
.icon--thick { stroke-width: 2.5; }