/* ============================================
   LAYOUT UTILITIES
   ============================================ */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 clamp(1rem, 4vw, 2rem);
}

.flex { display: flex; }
.flex-center { display: flex; justify-content: center; align-items: center; }
.flex-between { display: flex; justify-content: space-between; align-items: center; }
.flex-col { display: flex; flex-direction: column; }
.flex-wrap { flex-wrap: wrap; }
.gap-sm { gap: 0.5rem; }
.gap-md { gap: 1rem; }
.gap-lg { gap: 1.5rem; }

.grid { display: grid; }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1.5rem; }
.grid-3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 1.5rem; }

.text-center { text-align: center; }
.text-left { text-align: left; }

.hidden { display: none !important; }
.invisible { visibility: hidden; opacity: 0; }
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0,0,0,0);
    white-space: nowrap;
    border: 0;
}

/* ============================================
   APP LAYOUT SECTIONS
   ============================================ */
#app-section {
    min-height: 100vh;
    display: none;
    flex-direction: column;
}

#app-section.active {
    display: flex;
}

/* ============================================
   SECTION SPACING
   ============================================ */
.section {
    padding: clamp(3rem, 7vw, 6rem) 0;
}

.section-sm {
    padding: clamp(2rem, 4vw, 3.5rem) 0;
}

/* ============================================
   RESPONSIVE GRID
   ============================================ */
@media (max-width: 768px) {
    .grid-2 {
        grid-template-columns: 1fr;
    }
    .grid-3 {
        grid-template-columns: 1fr;
    }
}