/* ============================================================
   KELAS ONLINE PRO — Design System
   Identitas visual: clean white, modern, high-tech, premium,
   thin grid lines, soft borders, rounded cards, subtle motion.
   Font & warna disamakan dengan ekosistem produk Kang Lintang (ISAAC.ID).
   ============================================================ */

:root {
  /* ---- Warna inti (default, bisa dioverride via Customizer) ---- */
  --kop-bg:        #FFFFFF;
  --kop-ink:       #0B0F14;
  --kop-panel:     #0B0F14;
  --kop-mist:      #F5F7F8;
  --kop-mist-2:    #EEF1F2;
  --kop-border:    #E4E8EA;
  --kop-teal:      #14B8A6;
  --kop-teal-dark: #0F9485;
  --kop-teal-soft: rgba(20, 184, 166, 0.10);
  --kop-text:      #0B0F14;
  --kop-text-soft: #5B6670;
  --kop-text-mute: #8A949C;
  --kop-white:     #FFFFFF;
  --kop-success:   #16A34A;
  --kop-warning:   #D97706;
  --kop-danger:    #DC2626;

  /* ---- Tipografi ---- */
  --kop-font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --kop-font-mono:    'JetBrains Mono', 'SFMono-Regular', Consolas, monospace;

  /* ---- Radius & shadow ---- */
  --kop-radius-sm: 8px;
  --kop-radius-md: 14px;
  --kop-radius-lg: 20px;
  --kop-radius-full: 999px;
  --kop-shadow-sm: 0 1px 2px rgba(11,15,20,0.04);
  --kop-shadow-md: 0 4px 16px rgba(11,15,20,0.06);
  --kop-shadow-lg: 0 12px 32px rgba(11,15,20,0.10);

  /* ---- Spacing scale ---- */
  --kop-space-1: 4px;
  --kop-space-2: 8px;
  --kop-space-3: 12px;
  --kop-space-4: 16px;
  --kop-space-5: 24px;
  --kop-space-6: 32px;
  --kop-space-7: 48px;
  --kop-space-8: 64px;

  /* ---- Container ---- */
  --kop-container: 1180px;
}

/* ============================================================
   RESET DASAR
   ============================================================ */
*, *::before, *::after { box-sizing: border-box; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body.kelas-online-pro {
  margin: 0;
  background: var(--kop-bg);
  color: var(--kop-text);
  font-family: var(--kop-font-primary);
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.kop-mono { font-family: var(--kop-font-mono); }

img { max-width: 100%; height: auto; display: block; }

a { color: inherit; text-decoration: none; }

button { font-family: inherit; cursor: pointer; }

h1, h2, h3, h4, h5, h6 {
  margin: 0;
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1.2;
  color: var(--kop-ink);
}

p { margin: 0; }

/* ============================================================
   LAYOUT UTILITAS
   ============================================================ */
.kop-container {
  max-width: var(--kop-container);
  margin: 0 auto;
  padding: 0 var(--kop-space-5);
}

@media (max-width: 640px) {
  .kop-container { padding: 0 var(--kop-space-4); }
  body.kelas-online-pro { font-size: 14.5px; }
}

.kop-grid { display: grid; gap: var(--kop-space-5); }

.kop-flex { display: flex; align-items: center; }

/* ============================================================
   KOMPONEN — TOMBOL
   ============================================================ */
.kop-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--kop-space-2);
  padding: 11px 22px;
  border-radius: var(--kop-radius-sm);
  font-size: 14px;
  font-weight: 600;
  border: 1px solid transparent;
  transition: all .18s ease;
  white-space: nowrap;
}

.kop-btn-primary {
  background: var(--kop-teal);
  color: #fff;
  box-shadow: var(--kop-shadow-sm);
}
.kop-btn-primary:hover { background: var(--kop-teal-dark); transform: translateY(-1px); box-shadow: var(--kop-shadow-md); }

.kop-btn-dark {
  background: var(--kop-ink);
  color: #fff;
}
.kop-btn-dark:hover { background: #1a232c; }

.kop-btn-outline {
  background: transparent;
  border-color: var(--kop-border);
  color: var(--kop-ink);
}
.kop-btn-outline:hover { border-color: var(--kop-teal); color: var(--kop-teal-dark); }

.kop-btn-ghost {
  background: transparent;
  color: var(--kop-text-soft);
}
.kop-btn-ghost:hover { color: var(--kop-ink); }

.kop-btn-sm { padding: 7px 14px; font-size: 13px; }
.kop-btn-block { width: 100%; }

/* ============================================================
   KOMPONEN — CARD
   ============================================================ */
.kop-card {
  background: var(--kop-white);
  border: 1px solid var(--kop-border);
  border-radius: var(--kop-radius-md);
  box-shadow: var(--kop-shadow-sm);
  transition: box-shadow .2s ease, transform .2s ease;
}

.kop-card-hover:hover {
  box-shadow: var(--kop-shadow-lg);
  transform: translateY(-3px);
}

/* ============================================================
   KOMPONEN — BADGE
   ============================================================ */
.kop-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: var(--kop-radius-full);
  font-size: 11.5px;
  font-weight: 600;
  letter-spacing: 0.02em;
  background: var(--kop-mist);
  color: var(--kop-text-soft);
}
.kop-badge-teal { background: var(--kop-teal-soft); color: var(--kop-teal-dark); }
.kop-badge-dark { background: var(--kop-ink); color: #fff; }

/* ============================================================
   KOMPONEN — PROGRESS BAR
   ============================================================ */
.kop-progress {
  width: 100%;
  height: 8px;
  background: var(--kop-mist-2);
  border-radius: var(--kop-radius-full);
  overflow: hidden;
}
.kop-progress-bar {
  height: 100%;
  background: linear-gradient(90deg, var(--kop-teal), var(--kop-teal-dark));
  border-radius: var(--kop-radius-full);
  transition: width .4s ease;
}

/* ============================================================
   KOMPONEN — FORM
   ============================================================ */
.kop-field { margin-bottom: var(--kop-space-4); }
.kop-label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  color: var(--kop-ink);
  margin-bottom: 6px;
}
.kop-input,
.kop-select,
.kop-textarea {
  width: 100%;
  padding: 11px 14px;
  font-family: var(--kop-font-primary);
  font-size: 14px;
  background: var(--kop-white);
  border: 1px solid var(--kop-border);
  border-radius: var(--kop-radius-sm);
  color: var(--kop-text);
  transition: border-color .15s ease;
}
.kop-input:focus,
.kop-select:focus,
.kop-textarea:focus {
  outline: none;
  border-color: var(--kop-teal);
  box-shadow: 0 0 0 3px var(--kop-teal-soft);
}

/* ============================================================
   ACCESSIBILITY
   ============================================================ */
:focus-visible {
  outline: 2px solid var(--kop-teal);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

.kop-sr-only {
  position: absolute;
  width: 1px; height: 1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
}