/* ===========================================
   StudyMate Suite — Shared Glass Components
   .btn, .card-glass, .input, .badge, .modal, .tab
   =========================================== */

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  padding: 10px 20px; border-radius: var(--radius-xs);
  font-weight: 600; font-size: 0.9rem;
  font-family: var(--font);
  transition: var(--transition); cursor: pointer; border: none;
  text-decoration: none; line-height: 1.4;
}
.btn:hover { transform: translateY(-1px); box-shadow: var(--shadow-md); }
.btn:active { transform: translateY(0); }
.btn-sm { padding: 6px 14px; font-size: 0.82rem; }
.btn-lg { padding: 14px 28px; font-size: 1rem; }
.btn-icon { width: 36px; height: 36px; padding: 0; border-radius: var(--radius-xs); }

.btn-primary { background: linear-gradient(135deg, var(--primary), #818cf8); color: #fff; }
.btn-primary:hover { box-shadow: 0 4px 16px rgba(99,102,241,0.35); }
.btn-success { background: var(--success); color: #fff; }
.btn-danger { background: var(--danger); color: #fff; }
.btn-warning { background: var(--warning); color: #fff; }
.btn-ghost { background: transparent; color: var(--text-secondary); border: 1px solid var(--glass-border); }
.btn-ghost:hover { background: var(--glass-bg); border-color: var(--primary); color: var(--primary); }
.btn-outline { background: transparent; color: var(--primary); border: 1.5px solid var(--primary); }
.btn-outline:hover { background: var(--primary-soft); }

/* ---------- Glass Card ---------- */
.card-glass {
  background: var(--glass-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}
.card-glass:hover {
  background: var(--glass-bg-hover);
  border-color: var(--glass-border-hover);
  box-shadow: var(--shadow-md);
}

.card-glass-sm {
  padding: 16px;
  border-radius: var(--radius-sm);
}

/* ---------- Input / Form ---------- */
.input {
  width: 100%;
  padding: 10px 14px;
  background: var(--surface);
  border: 1.5px solid var(--glass-border);
  border-radius: var(--radius-xs);
  font-size: 0.9rem;
  font-family: var(--font);
  color: var(--text);
  transition: var(--transition);
  outline: none;
}
.input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(99,102,241,0.12);
}
.input::placeholder { color: var(--text-muted); }
textarea.input { resize: vertical; min-height: 80px; }
select.input { cursor: pointer; }
label { font-size: 0.85rem; font-weight: 500; color: var(--text-secondary); margin-bottom: 4px; display: block; }
.form-group { margin-bottom: 16px; }

/* ---------- Badge ---------- */
.badge {
  display: inline-flex; align-items: center; gap: 4px;
  padding: 3px 12px;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 500;
  white-space: nowrap;
}
.badge-primary { background: var(--primary-soft); color: var(--primary); border: 1px solid rgba(99,102,241,0.15); }
.badge-success { background: var(--success-soft); color: var(--success); border: 1px solid rgba(16,185,129,0.15); }
.badge-warning { background: var(--warning-soft); color: var(--warning); border: 1px solid rgba(245,158,11,0.15); }
.badge-danger { background: var(--danger-soft); color: var(--danger); border: 1px solid rgba(239,68,68,0.15); }

/* ---------- Modal ---------- */
.modal-overlay {
  display: none; position: fixed; inset: 0;
  background: rgba(15,23,42,0.5);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  z-index: 1000;
  align-items: center; justify-content: center; padding: 20px;
}
.modal-overlay.active { display: flex; }
.modal-glass {
  background: var(--glass-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius);
  padding: 28px;
  max-width: 520px;
  width: 100%;
  max-height: 85vh;
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
  animation: modalIn 0.25s ease;
}
@keyframes modalIn {
  from { opacity: 0; transform: scale(0.95) translateY(10px); }
  to { opacity: 1; transform: scale(1) translateY(0); }
}
.modal-header {
  display: flex; justify-content: space-between; align-items: center;
  margin-bottom: 20px; padding-bottom: 14px;
  border-bottom: 1px solid var(--glass-border);
}
.modal-header h2 { font-size: 1.2rem; font-weight: 700; display: flex; align-items: center; gap: 8px; }
.modal-close {
  width: 32px; height: 32px; border-radius: 50%;
  border: 1px solid var(--glass-border);
  background: transparent;
  display: flex; align-items: center; justify-content: center;
  cursor: pointer; font-size: 1rem; color: var(--text-muted);
  transition: var(--transition);
}
.modal-close:hover { background: var(--danger-soft); border-color: var(--danger); color: var(--danger); }

/* ---------- Tabs ---------- */
.tab-bar {
  display: flex; gap: 2px;
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  padding: 4px;
  margin-bottom: 20px;
}
.tab-item {
  flex: 1; padding: 10px 16px;
  text-align: center; cursor: pointer;
  font-weight: 500; font-size: 0.85rem;
  color: var(--text-secondary);
  border-radius: var(--radius-xs);
  transition: var(--transition);
  border: none; background: transparent;
  font-family: var(--font);
  display: flex; align-items: center; justify-content: center; gap: 6px;
}
.tab-item:hover { color: var(--text); background: rgba(255,255,255,0.5); }
.tab-item.active { background: var(--surface); color: var(--primary); font-weight: 600; box-shadow: var(--shadow-sm); white-space: nowrap; }

/* ---------- Progress Bar ---------- */
.progress-bar {
  width: 100%; height: 6px;
  background: var(--glass-bg);
  border-radius: 3px;
  overflow: hidden;
}
.progress-fill {
  height: 100%; border-radius: 3px;
  background: linear-gradient(90deg, var(--primary), #818cf8);
  transition: width 0.4s ease;
}

/* ---------- Toggle Switch ---------- */
.toggle {
  position: relative; display: inline-flex; align-items: center; gap: 10px;
  cursor: pointer;
}
.toggle input { position: absolute; opacity: 0; width: 0; height: 0; }
.toggle-slider {
  width: 40px; height: 22px; background: var(--glass-border);
  border-radius: 11px; transition: var(--transition); flex-shrink: 0;
}
.toggle-slider::after {
  content: ''; position: absolute; top: 3px; left: 3px;
  width: 16px; height: 16px; border-radius: 50%;
  background: #fff; transition: var(--transition); box-shadow: 0 1px 3px rgba(0,0,0,0.2);
}
.toggle input:checked + .toggle-slider { background: var(--primary); }
.toggle input:checked + .toggle-slider::after { left: 21px; }
.toggle-label { font-size: 0.88rem; color: var(--text-secondary); }

/* ---------- Score Ring (SVG circular) ---------- */
.score-ring { position: relative; display: inline-flex; align-items: center; justify-content: center; }
.score-ring svg { transform: rotate(-90deg); }
.score-ring circle { fill: none; stroke-width: 8; }
.score-ring-bg { stroke: var(--glass-border); }
.score-ring-fill { stroke: var(--primary); stroke-linecap: round; transition: stroke-dashoffset 1s ease; }
.score-ring-text { position: absolute; font-size: 1.5rem; font-weight: 800; color: var(--text); }

/* ---------- Divider ---------- */
.divider { border: none; border-top: 1px solid var(--glass-border); margin: 24px 0; }

/* ---------- Empty state ---------- */
.empty-state {
  text-align: center; padding: 40px 20px;
  color: var(--text-muted); font-size: 0.9rem;
}
.empty-state i { font-size: 2rem; margin-bottom: 12px; display: block; }

/* ---------- Notification toast ---------- */
.toast {
  position: fixed; top: 20px; right: 20px;
  padding: 14px 20px; border-radius: var(--radius-sm);
  font-weight: 500; font-size: 0.9rem;
  z-index: 2000;
  backdrop-filter: blur(12px);
  box-shadow: var(--shadow-lg);
  animation: toastIn 0.3s ease, toastOut 0.3s ease 3s forwards;
  display: flex; align-items: center; gap: 10px;
}
.toast-success { background: rgba(16,185,129,0.9); color: #fff; }
.toast-error { background: rgba(239,68,68,0.9); color: #fff; }
.toast-info { background: rgba(99,102,241,0.9); color: #fff; }
@keyframes toastIn { from { opacity: 0; transform: translateX(40px); } to { opacity: 1; transform: translateX(0); } }
@keyframes toastOut { from { opacity: 1; } to { opacity: 0; transform: translateX(40px); } }