/* buttons */
.btn-add {
  display: flex; align-items: center; gap: 8px;
  background: var(--accent); border: none; border-radius: 8px; padding: 11px 20px;
  font-family: 'Syne', sans-serif; font-size: 13px; font-weight: 700; color: #fff;
  cursor: pointer; transition: transform 0.2s, background-color 0.2s, border-color 0.2s, color 0.2s; white-space: nowrap;
}
.btn-add:hover {
  background: var(--accent-light);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(var(--accent-rgb), 0.45);
}
.btn-add:active { transform: translateY(0) scale(0.97); box-shadow: none; }
.btn-add .plus { font-size: 18px; line-height: 1; }

.btn-secondary {
  background: var(--surface); border: 1px solid var(--border); border-radius: 8px; padding: 10px 16px;
  font-family: 'JetBrains Mono', monospace; font-size: 11px; color: var(--text-muted);
  cursor: pointer; transition: transform 0.2s, background-color 0.2s, border-color 0.2s, color 0.2s; text-transform: uppercase; letter-spacing: 0.06em;
}
.btn-secondary:hover {
  border-color: var(--border2);
  color: var(--text);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px var(--shadow-sm);
}
.btn-secondary:active { transform: translateY(0) scale(0.97); box-shadow: none; }

.btn-action {
  background: var(--surface2); border: 1px solid var(--border); border-radius: 8px; padding: 10px 18px;
  font-family: 'Syne', sans-serif; font-size: 12px; font-weight: 600; color: var(--text);
  cursor: pointer; transition: transform 0.2s, background-color 0.2s, border-color 0.2s, color 0.2s; white-space: nowrap;
}
.btn-action:hover {
  background: var(--surface3);
  border-color: var(--border2);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px var(--shadow-sm);
}
.btn-action:active { transform: translateY(0) scale(0.97); box-shadow: none; }

.btn-settings {
  background: rgba(var(--accent-rgb), 0.15); border: 1px solid rgba(var(--accent-rgb), 0.4); border-radius: 8px; padding: 10px 18px;
  font-family: 'Syne', sans-serif; font-size: 13px; font-weight: 700; color: var(--text);
  cursor: pointer; transition: transform 0.2s, background-color 0.2s, border-color 0.2s, color 0.2s; white-space: nowrap;
}
.btn-settings:hover {
  background: rgba(var(--accent-rgb), 0.25);
  border-color: var(--accent);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(var(--accent-rgb), 0.2);
}
.btn-settings:active { transform: translateY(0) scale(0.97); box-shadow: none; }

.btn-action-danger {
  color: var(--hard); border-color: rgba(var(--hard-rgb), 0.3);
}
.btn-action-danger:hover {
  background: var(--hard-bg); border-color: rgba(var(--hard-rgb), 0.6);
}
.btn-logout {
  background: transparent; border: 1px solid rgba(var(--hard-rgb), 0.3); border-radius: 8px; padding: 10px 16px;
  font-family: 'JetBrains Mono', monospace; font-size: 11px; color: var(--hard);
  cursor: pointer; transition: transform 0.2s, background-color 0.2s, border-color 0.2s, color 0.2s; text-transform: uppercase; letter-spacing: 0.06em;
  text-decoration: none; display: inline-flex; align-items: center;
}
.btn-logout:hover { background: var(--hard-bg); border-color: rgba(var(--hard-rgb), 0.6); transform: translateY(-1px); }
.btn-logout:active { transform: scale(0.97); }

/* Used in modal footers */
.btn-submit {
  background: var(--accent); border: none; border-radius: 8px; padding: 11px 24px;
  font-family: 'Syne', sans-serif; font-size: 13px; font-weight: 700; color: #fff;
  cursor: pointer; transition: transform 0.2s, background-color 0.2s, border-color 0.2s, color 0.2s;
}
.btn-submit:hover { background: var(--accent-light); transform: translateY(-1px); box-shadow: 0 4px 16px rgba(var(--accent-rgb), 0.4); }
.btn-submit:active { transform: scale(0.97); box-shadow: none; }
.btn-submit:disabled { opacity: 0.5; cursor: not-allowed; }

.btn-cancel {
  background: transparent; border: 1px solid var(--border); border-radius: 8px; padding: 11px 20px;
  font-family: 'Syne', sans-serif; font-size: 13px; color: var(--text-muted);
  cursor: pointer; transition: transform 0.2s, background-color 0.2s, border-color 0.2s, color 0.2s;
}
.btn-cancel:hover { border-color: var(--border2); color: var(--text); }

/* Destructive action (e.g. confirm logout) */
.btn-danger {
  background: var(--hard); border: none; border-radius: 8px; padding: 11px 24px;
  font-family: 'Syne', sans-serif; font-size: 13px; font-weight: 700; color: #fff;
  cursor: pointer; transition: transform 0.2s, background-color 0.2s, border-color 0.2s, color 0.2s;
}
.btn-danger:hover { background: var(--hard-light); transform: translateY(-1px); box-shadow: 0 4px 16px rgba(var(--hard-rgb), 0.35); }
.btn-danger:active { transform: scale(0.97); box-shadow: none; }

/* highlighted feature buttons */
.btn-feature {
  display: flex; align-items: center; justify-content: center; gap: 12px;
  background: linear-gradient(135deg, rgba(var(--accent-rgb), 0.12), var(--easy-bg));
  border: 1px solid rgba(var(--accent-rgb), 0.3); border-radius: 12px;
  padding: 16px 24px;
  cursor: pointer; transition: transform 0.25s cubic-bezier(0.4, 0, 0.2, 1), background 0.25s, border-color 0.25s;
  flex: 1; min-width: 240px;
}
.btn-feature:hover {
  background: linear-gradient(135deg, rgba(var(--accent-rgb), 0.22), rgba(var(--easy-rgb), 0.18));
  border-color: var(--accent);
  transform: translateY(-3px);
  box-shadow: 0 10px 30px var(--shadow-md);
}
.btn-feature:active { transform: scale(0.98) translateY(0); box-shadow: none; }
.btn-feature .feature-icon { font-size: 26px; line-height: 1; }
.btn-feature .feature-text { font-family: 'Syne', sans-serif; font-size: 16px; font-weight: 700; color: #fff; letter-spacing: 0.04em; }

[data-theme="light"] .btn-feature .feature-text { color: var(--text); }

.study-tools-bar {
  display: flex; gap: 16px; margin-bottom: 24px; flex-wrap: wrap; margin-top: -16px;
}

@media (max-width: 768px) {
  .btn-feature { flex: 1 1 calc(50% - 8px); min-width: 0; padding: 12px 10px; }
  .btn-feature .feature-text { font-size: 13px; }
  .btn-feature .feature-icon { font-size: 20px; }
  .study-tools-bar { gap: 8px; }
}