/* =====================================================
   VISION EDUCATION — GLOBAL THEME ENGINE v4
   Light (default) + Dark mode via [data-theme="dark"]
   ===================================================== */

/* ── LIGHT MODE (default) ── */
:root, [data-theme="light"] {
  --bg:              #f0f2f5;
  --bg-card:         #ffffff;
  --bg-card-hover:   #f8fafc;
  --bg-sidebar:      #ffffff;
  --bg-input:        #f8fafc;
  --bg-hero:         #f0f2f5;
  --bg-header:       rgba(255,255,255,0.92);

  --primary:         #1a1a2e;
  --primary-hover:   #2d2d4e;
  --primary-dim:     rgba(251,191,36,0.10);
  --gold:            #fbbf24;
  --indigo:          #6366f1;
  --emerald:         #10b981;
  --red:             #ef4444;

  --text-primary:    #1a1a2e;
  --text-secondary:  #374151;
  --text-muted:      #64748b;

  --border:          #e2e8f0;
  --border-bright:   #94a3b8;
  --border-accent:   rgba(251,191,36,0.35);
  --border-input:    #e2e8f0;

  --success:         #10b981;
  --error:           #ef4444;
  --warning:         #f59e0b;

  --radius-sm:       8px;
  --radius-md:       14px;
  --radius-lg:       20px;
  --font-main:       'Outfit', sans-serif;
  --font-mono:       'JetBrains Mono', monospace;

  --shadow-sm:       0 1px 4px rgba(0,0,0,0.06);
  --shadow-md:       0 4px 20px rgba(0,0,0,0.08);
  --shadow-lg:       0 8px 40px rgba(0,0,0,0.10);
  --shadow-premium:  0 20px 60px rgba(0,0,0,0.12);

  --brand-accent:    #fbbf24;
  color-scheme: light;
}

/* ── DARK MODE ── */
[data-theme="dark"] {
  --bg:              #05080f;
  --bg-card:         #0d1117;
  --bg-card-hover:   #111827;
  --bg-sidebar:      #080b12;
  --bg-input:        rgba(255,255,255,0.05);
  --bg-hero:         #07090f;
  --bg-header:       rgba(5,8,15,0.88);

  --primary:         #6366f1;
  --primary-hover:   #818cf8;
  --primary-dim:     rgba(99,102,241,0.12);
  --gold:            #fbbf24;
  --indigo:          #6366f1;
  --emerald:         #10b981;
  --red:             #f87171;

  --text-primary:    #f1f5f9;
  --text-secondary:  #94a3b8;
  --text-muted:      #64748b;

  --border:          rgba(255,255,255,0.07);
  --border-bright:   rgba(255,255,255,0.15);
  --border-accent:   rgba(99,102,241,0.35);
  --border-input:    rgba(255,255,255,0.12);

  --success:         #22c55e;
  --error:           #f87171;
  --warning:         #f59e0b;

  --shadow-sm:       0 2px 8px rgba(0,0,0,0.4);
  --shadow-md:       0 4px 20px rgba(0,0,0,0.6);
  --shadow-lg:       0 8px 40px rgba(0,0,0,0.7);
  --shadow-premium:  0 20px 60px rgba(0,0,0,0.8);

  --brand-accent:    #818cf8;
  color-scheme: dark;
}

/* ── Global base ── */
*, *::before, *::after { box-sizing: border-box; }

html, body {
  background-color: var(--bg);
  color: var(--text-primary);
  transition: background-color 0.25s ease, color 0.2s ease;
}

/* ── Theme toggle button (universal) ── */
.theme-toggle-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px; height: 36px;
  border-radius: 50%;
  background: var(--bg-input);
  border: 1.5px solid var(--border);
  color: var(--text-muted);
  cursor: pointer;
  transition: all 0.2s;
  font-size: 0; /* hide text */
  padding: 0;
}
.theme-toggle-btn:hover {
  background: var(--primary);
  color: var(--gold);
  border-color: var(--primary);
}

/* light icon shown in dark mode, dark icon shown in light mode */
.theme-icon-dark  { display: block; }
.theme-icon-light { display: none;  }
[data-theme="dark"] .theme-icon-dark  { display: none;  }
[data-theme="dark"] .theme-icon-light { display: block; }

/* ── Shared utility ── */
.social-youtube {
  color: var(--text-secondary);
  transition: all 0.2s;
  display: inline-flex; align-items: center; justify-content: center;
}
.social-youtube:hover {
  color: #ff0000 !important;
  filter: drop-shadow(0 0 6px rgba(255,0,0,0.3));
}

/* scrollbar */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border-bright); border-radius: 100px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }