/**
 * Lecture Mind - Utility Classes for Student Playground
 *
 * Typography, spacing, layout, and visual utilities.
 * All values reference CSS custom properties — zero hardcoded pixels.
 *
 * IMPORTANT: Load AFTER tokens-v2.css and BEFORE landing.css.
 * Playground-specific utilities use the `sp-` prefix.
 */

/* ============================================
   FLUID DISPLAY TYPOGRAPHY
   ============================================ */
.text-display-xl {
  font-family: var(--font-display-sp);
  font-size: clamp(2.25rem, 4vw + 1rem, 4rem);
  font-weight: var(--font-bold);
  line-height: var(--leading-none);
  letter-spacing: var(--tracking-tighter);
}

.text-display-lg {
  font-family: var(--font-display-sp);
  font-size: clamp(1.875rem, 3vw + 0.75rem, 3rem);
  font-weight: var(--font-bold);
  line-height: var(--leading-tight);
  letter-spacing: var(--tracking-tight);
}

.text-display-md {
  font-family: var(--font-display-sp);
  font-size: clamp(1.5rem, 2vw + 0.5rem, 2.25rem);
  font-weight: var(--font-semibold);
  line-height: var(--leading-tight);
  letter-spacing: var(--tracking-tight);
}

/* ============================================
   TEXT UTILITIES
   ============================================ */
.text-gradient {
  background: var(--gradient-brand);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.text-balance {
  text-wrap: balance;
}

.text-truncate {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.text-line-clamp-2 {
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.text-line-clamp-3 {
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.text-line-clamp-4 {
  display: -webkit-box;
  -webkit-line-clamp: 4;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* ============================================
   SPACING UTILITIES
   ============================================ */

/* Margin */
.m-0 { margin: var(--space-0); }
.m-2 { margin: var(--space-2); }
.m-4 { margin: var(--space-4); }
.mx-auto { margin-inline: auto; }
.my-4 { margin-block: var(--space-4); }
.my-6 { margin-block: var(--space-6); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }

/* Padding */
.p-0 { padding: var(--space-0); }
.p-2 { padding: var(--space-2); }
.p-3 { padding: var(--space-3); }
.p-4 { padding: var(--space-4); }
.p-6 { padding: var(--space-6); }
.p-8 { padding: var(--space-8); }
.px-4 { padding-inline: var(--space-4); }
.px-6 { padding-inline: var(--space-6); }
.py-4 { padding-block: var(--space-4); }
.py-6 { padding-block: var(--space-6); }

/* Gap */
.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }

/* ============================================
   LAYOUT UTILITIES
   ============================================ */
.flex { display: flex; }
.flex-col { flex-direction: column; }
.flex-row { flex-direction: row; }
.flex-wrap { flex-wrap: wrap; }
.flex-1 { flex: 1 1 0%; }
.flex-none { flex: none; }
.flex-shrink-0 { flex-shrink: 0; }

.items-start { align-items: flex-start; }
.items-center { align-items: center; }
.items-end { align-items: flex-end; }
.items-stretch { align-items: stretch; }

.justify-start { justify-content: flex-start; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.justify-end { justify-content: flex-end; }

.grid { display: grid; }
.grid-cols-1 { grid-template-columns: repeat(1, minmax(0, 1fr)); }
.grid-cols-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-cols-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid-cols-4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

.col-span-2 { grid-column: span 2 / span 2; }
.col-span-3 { grid-column: span 3 / span 3; }
.col-span-full { grid-column: 1 / -1; }

/* ============================================
   VISUAL UTILITIES
   ============================================ */
.glass {
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border: 1px solid var(--glass-border);
  box-shadow: var(--glass-shadow);
}

.glass-heavy {
  background: var(--glass-bg-heavy);
  backdrop-filter: blur(var(--glass-blur-heavy));
  -webkit-backdrop-filter: blur(var(--glass-blur-heavy));
  border: 1px solid var(--glass-border);
  box-shadow: var(--glass-shadow);
}

.rounded-sm { border-radius: var(--radius-sm); }
.rounded-md { border-radius: var(--radius-md); }
.rounded-lg { border-radius: var(--radius-lg); }
.rounded-xl { border-radius: var(--radius-xl); }
.rounded-2xl { border-radius: var(--radius-2xl); }
.rounded-full { border-radius: var(--radius-full); }

.shadow-sm { box-shadow: var(--shadow-sm); }
.shadow-md { box-shadow: var(--shadow-md); }
.shadow-lg { box-shadow: var(--shadow-lg); }
.shadow-xl { box-shadow: var(--shadow-xl); }
.shadow-none { box-shadow: none; }

.gradient-brand { background: var(--gradient-brand); }
.gradient-mastery { background: var(--gradient-mastery); }
.gradient-hero { background: var(--gradient-hero); }
.gradient-surface { background: var(--gradient-surface); }

/* ============================================
   DISPLAY & VISIBILITY UTILITIES
   ============================================ */
.inline-flex { display: inline-flex; }
.w-full { width: 100%; }
.h-full { height: 100%; }
.overflow-hidden { overflow: hidden; }
.relative { position: relative; }
.absolute { position: absolute; }
.inset-0 { inset: 0; }
.opacity-0 { opacity: 0; }
.pointer-events-none { pointer-events: none; }
.cursor-pointer { cursor: pointer; }
.select-none { user-select: none; }

.transition-all {
  transition-property: all;
  transition-duration: var(--duration-normal);
  transition-timing-function: var(--ease-out);
}

.transition-colors {
  transition-property: color, background-color, border-color;
  transition-duration: var(--duration-normal);
  transition-timing-function: var(--ease-out);
}

.transition-transform {
  transition-property: transform;
  transition-duration: var(--duration-normal);
  transition-timing-function: var(--ease-out);
}

/* ============================================
   PLAYGROUND-SPECIFIC UTILITIES (sp- prefix)
   ============================================ */

/* Playground container */
.sp-container {
  max-width: var(--sp-container-max, 75rem);
  margin-inline: auto;
  padding-inline: var(--space-4);
}

/* Playground section spacing */
.sp-section {
  padding-block: var(--space-12);
}

/* Card grid for library view */
.sp-card-grid {
  display: grid;
  grid-template-columns: repeat(1, minmax(0, 1fr));
  gap: var(--space-4);
}

/* Study session layout */
.sp-study-layout {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-6);
  max-width: var(--sp-study-max, 37.5rem);
  margin-inline: auto;
}

/* ============================================
   RESPONSIVE VARIANTS (640px / 768px / 1024px)
   ============================================ */
@media (min-width: 640px) {
  .sm\:grid-cols-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .sm\:flex-row { flex-direction: row; }
  .sm\:block { display: block; }
  .sm\:hidden { display: none; }

  .sp-card-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (min-width: 768px) {
  .md\:grid-cols-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .md\:grid-cols-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .md\:flex-row { flex-direction: row; }
  .md\:block { display: block; }
  .md\:hidden { display: none; }

  .sp-card-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .sp-container { padding-inline: var(--space-6); }
}

@media (min-width: 1024px) {
  .lg\:grid-cols-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .lg\:grid-cols-4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .lg\:flex-row { flex-direction: row; }
  .lg\:block { display: block; }
  .lg\:hidden { display: none; }

  .sp-card-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .sp-container { padding-inline: var(--space-8); }
}