/* ==========================================================================
   DevPilot-AI — DSA Problem Detail & Revision Styles
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. Problem Detail Container & Layout
   -------------------------------------------------------------------------- */
.dsa-problem-view-container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding-bottom: 5rem;
}

/* Breadcrumb & Top Bar */
.dp-breadcrumb-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1.5rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--color-outline-variant, #e2e8f0);
}

.dp-breadcrumb-nav {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  font-size: 0.8125rem;
  color: var(--color-on-surface-variant, #64748b);
  font-weight: 500;
}

.dp-breadcrumb-item {
  color: inherit;
  text-decoration: none;
  transition: color 0.15s ease;
}

.dp-breadcrumb-item:hover {
  color: var(--color-primary, #4f46e5);
}

.dp-breadcrumb-current {
  color: var(--color-on-surface, #0f172a);
  font-weight: 700;
}

.dp-btn-back {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  padding: 0.45rem 0.875rem;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--color-on-surface-variant, #475569);
  background: var(--color-surface, #ffffff);
  border: 1px solid var(--color-outline-variant, #cbd5e1);
  border-radius: var(--radius-md, 8px);
  cursor: pointer;
  transition: all 0.2s ease;
}

.dp-btn-back:hover {
  color: var(--color-primary, #4f46e5);
  border-color: var(--color-primary, #4f46e5);
  background: rgba(79, 70, 229, 0.04);
}

/* --------------------------------------------------------------------------
   2. Problem Header Card
   -------------------------------------------------------------------------- */
.dp-header-card {
  background: var(--color-surface, #ffffff);
  border: 1px solid var(--color-outline-variant, #e2e8f0);
  border-radius: var(--radius-lg, 12px);
  padding: 1.75rem;
  box-shadow: var(--shadow-card, 0 1px 3px 0 rgba(0, 0, 0, 0.05));
  margin-bottom: 2rem;
  position: relative;
  overflow: hidden;
}

.dp-header-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1.25rem;
  margin-bottom: 1.25rem;
}

.dp-title-group {
  flex: 1;
  min-width: 280px;
}

.dp-badges-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
}

.dp-badge-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.25rem 0.65rem;
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 700;
}

.dp-badge-cat {
  background: rgba(79, 70, 229, 0.08);
  color: #4f46e5;
  border: 1px solid rgba(79, 70, 229, 0.2);
}

.dp-badge-pattern {
  background: rgba(14, 165, 233, 0.08);
  color: #0284c7;
  border: 1px solid rgba(14, 165, 233, 0.2);
}

.dp-badge-diff-easy {
  background: rgba(16, 185, 129, 0.1);
  color: #059669;
  border: 1px solid rgba(16, 185, 129, 0.25);
}

.dp-badge-diff-medium {
  background: rgba(245, 158, 11, 0.1);
  color: #d97706;
  border: 1px solid rgba(245, 158, 11, 0.25);
}

.dp-badge-diff-hard {
  background: rgba(244, 63, 94, 0.1);
  color: #e11d48;
  border: 1px solid rgba(244, 63, 94, 0.25);
}

.dp-badge-status-solved {
  background: rgba(16, 185, 129, 0.15);
  color: #047857;
  border: 1px solid rgba(16, 185, 129, 0.3);
}

.dp-badge-status-unsolved {
  background: #f1f5f9;
  color: #64748b;
  border: 1px solid #cbd5e1;
}

.dp-badge-status-review {
  background: rgba(234, 179, 8, 0.15);
  color: #b45309;
  border: 1px solid rgba(234, 179, 8, 0.3);
}

/* Solve Quality Badges in Problem Detail */
.dp-badge-quality-self {
  background: rgba(16, 185, 129, 0.12);
  color: #059669;
  border: 1px solid rgba(16, 185, 129, 0.3);
}

.dp-badge-quality-help30 {
  background: rgba(245, 158, 11, 0.15);
  color: #d97706;
  border: 1px solid rgba(245, 158, 11, 0.35);
}

.dp-badge-quality-help50 {
  background: rgba(249, 115, 22, 0.15);
  color: #ea580c;
  border: 1px solid rgba(249, 115, 22, 0.35);
}

.dp-badge-quality-cross {
  background: rgba(244, 63, 94, 0.15);
  color: #e11d48;
  border: 1px solid rgba(244, 63, 94, 0.35);
}

/* Honesty Revision Notice Banner in Detail View */
.dp-revision-notice {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
  padding: 0.75rem 1rem;
  border-radius: 8px;
  margin-top: 1rem;
  font-size: 0.8125rem;
  line-height: 1.4;
}

.dp-notice-help30 {
  background: #fffbeb;
  border: 1px solid #fde68a;
  color: #92400e;
}

.dp-notice-help50 {
  background: #fff7ed;
  border: 1px solid #fed7aa;
  color: #9a3412;
}

.dp-notice-cross {
  background: #fff1f2;
  border: 1px solid #fecdd3;
  color: #9f1239;
}

.dp-btn-re-eval-notice {
  padding: 0.35rem 0.75rem;
  font-size: 0.75rem;
  font-weight: 700;
  border-radius: 6px;
  border: 1px solid currentColor;
  background: rgba(255, 255, 255, 0.85);
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.15s ease;
}

.dp-btn-re-eval-notice:hover {
  background: #ffffff;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.dp-problem-title {
  font-size: 1.625rem;
  font-weight: 800;
  color: var(--color-on-surface, #0f172a);
  line-height: 1.25;
  font-family: 'Plus Jakarta Sans', sans-serif;
  margin-bottom: 0.25rem;
}

.dp-problem-num {
  color: var(--color-primary, #4f46e5);
  margin-right: 0.35rem;
}

/* Problem Action Buttons */
.dp-actions-toolbar {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.625rem;
}

.dp-btn-action {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.5rem 1rem;
  font-size: 0.8125rem;
  font-weight: 600;
  border-radius: var(--radius-md, 8px);
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
}

.dp-btn-leetcode {
  background: #fff7ed;
  color: #c2410c;
  border: 1px solid #fdba74;
}

.dp-btn-leetcode:hover {
  background: #ffedd5;
  border-color: #fb923c;
  transform: translateY(-1px);
}

.dp-btn-review {
  background: #f8fafc;
  color: #475569;
  border: 1px solid #cbd5e1;
}

.dp-btn-review:hover {
  background: #f1f5f9;
  color: #b45309;
}

.dp-btn-review.in-review {
  background: #fefce8;
  color: #b45309;
  border-color: #fde047;
}

.dp-btn-solve-rate {
  background: var(--color-primary, #4f46e5);
  color: #ffffff;
  border: 1px solid var(--color-primary, #4f46e5);
  box-shadow: 0 1px 2px rgba(79, 70, 229, 0.2);
}

.dp-btn-solve-rate:hover {
  background: var(--color-primary-dark, #4338ca);
}

/* --------------------------------------------------------------------------
   3. Interactive Hint System
   -------------------------------------------------------------------------- */
.dp-hints-card {
  background: linear-gradient(135deg, #f8fafc 0%, #f1f5f9 100%);
  border: 1px solid #e2e8f0;
  border-radius: var(--radius-lg, 12px);
  padding: 1.25rem;
  margin-bottom: 2rem;
}

.dp-hints-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.dp-hints-title {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9375rem;
  font-weight: 700;
  color: #1e293b;
}

.dp-hints-badge {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.15rem 0.5rem;
  border-radius: 9999px;
  background: rgba(99, 102, 241, 0.1);
  color: #4f46e5;
}

.dp-hints-buttons {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.dp-hint-trigger {
  padding: 0.35rem 0.75rem;
  font-size: 0.75rem;
  font-weight: 600;
  background: #ffffff;
  color: #334155;
  border: 1px solid #cbd5e1;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.15s ease;
}

.dp-hint-trigger:hover {
  background: #f8fafc;
  border-color: #6366f1;
  color: #4f46e5;
}

.dp-hint-trigger.revealed {
  background: #eef2ff;
  color: #4f46e5;
  border-color: #c7d2fe;
}

.dp-hint-box {
  background: #ffffff;
  border: 1px solid #e2e8f0;
  border-left: 3px solid #6366f1;
  border-radius: 8px;
  padding: 0.875rem 1rem;
  margin-top: 0.5rem;
  font-size: 0.8125rem;
  color: #334155;
  line-height: 1.5;
  display: none;
}

.dp-hint-box.open {
  display: block;
  animation: dpFadeIn 0.2s ease-out;
}

/* --------------------------------------------------------------------------
   4. 15-Section Step-by-Step Thought Process
   -------------------------------------------------------------------------- */
.dp-sections-container {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.dp-section-card {
  background: var(--color-surface, #ffffff);
  border: 1px solid var(--color-outline-variant, #e2e8f0);
  border-radius: var(--radius-lg, 12px);
  padding: 1.5rem;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.03);
}

.dp-section-title {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  font-size: 1.0625rem;
  font-weight: 800;
  color: #0f172a;
  margin-bottom: 1rem;
  padding-bottom: 0.625rem;
  border-bottom: 1px solid #f1f5f9;
}

.dp-sec-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  background: #eef2ff;
  color: #4f46e5;
  border-radius: 6px;
  font-size: 0.75rem;
  font-weight: 800;
  flex-shrink: 0;
}

.dp-section-content {
  font-size: 0.875rem;
  color: #334155;
  line-height: 1.65;
}

/* Recognition Signals list */
.dp-signals-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 0.75rem;
  margin-top: 0.5rem;
}

.dp-signal-item {
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
  padding: 0.75rem 1rem;
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  font-size: 0.8125rem;
  color: #1e293b;
  font-weight: 500;
}

.dp-signal-item .material-symbols-outlined {
  color: #4f46e5;
  font-size: 18px;
  flex-shrink: 0;
}

/* Approach numbered steps */
.dp-approach-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.625rem;
}

.dp-approach-step {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 0.75rem 1rem;
  background: #f8fafc;
  border-radius: 8px;
  font-size: 0.875rem;
  color: #334155;
}

.dp-step-index {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  border-radius: 9999px;
  background: #e0e7ff;
  color: #4338ca;
  font-size: 0.75rem;
  font-weight: 700;
  flex-shrink: 0;
  margin-top: 2px;
}

/* Walkthrough Table */
.dp-table-wrap {
  width: 100%;
  max-width: 100%;
  overflow-x: auto;
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  margin-top: 0.75rem;
  -webkit-overflow-scrolling: touch;
}

.dp-walkthrough-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.8125rem;
  text-align: left;
  white-space: nowrap;
}

.dp-walkthrough-table th {
  background: #f8fafc;
  color: #475569;
  font-weight: 700;
  padding: 0.625rem 0.875rem;
  border-bottom: 1px solid #e2e8f0;
  text-transform: uppercase;
  font-size: 0.6875rem;
  letter-spacing: 0.05em;
}

.dp-walkthrough-table td {
  padding: 0.625rem 0.875rem;
  border-bottom: 1px solid #f1f5f9;
  color: #334155;
  font-family: var(--font-mono, monospace);
  font-size: 0.8125rem;
}

.dp-walkthrough-table tr:last-child td {
  border-bottom: none;
}

.dp-walkthrough-table tr:hover td {
  background: #f8fafc;
}

/* Edge Cases Grid */
.dp-edge-cases-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 0.75rem;
  margin-top: 0.75rem;
}

.dp-edge-case-card {
  padding: 0.875rem;
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  border-radius: 8px;
}

.dp-edge-case-title {
  font-size: 0.8125rem;
  font-weight: 700;
  color: #0f172a;
  font-family: var(--font-mono, monospace);
  margin-bottom: 0.25rem;
}

.dp-edge-case-exp {
  font-size: 0.75rem;
  color: #64748b;
  line-height: 1.4;
}

/* --------------------------------------------------------------------------
   5. Multi-Language Code Block & Explanation
   -------------------------------------------------------------------------- */
.dp-code-container {
  background: #0f172a;
  border: 1px solid #1e293b;
  border-radius: var(--radius-lg, 12px);
  overflow: hidden;
  margin-top: 1rem;
}

.dp-code-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: #1e293b;
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid #334155;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.dp-lang-tabs {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.dp-lang-tab {
  padding: 0.35rem 0.75rem;
  font-size: 0.75rem;
  font-weight: 600;
  color: #94a3b8;
  background: transparent;
  border: 1px solid transparent;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.15s ease;
}

.dp-lang-tab:hover {
  color: #f8fafc;
  background: rgba(255, 255, 255, 0.05);
}

.dp-lang-tab.active {
  color: #ffffff;
  background: #334155;
  border-color: #475569;
}

.dp-btn-copy {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.35rem 0.65rem;
  font-size: 0.75rem;
  font-weight: 600;
  color: #cbd5e1;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.15s ease;
}

.dp-btn-copy:hover {
  background: rgba(255, 255, 255, 0.15);
  color: #ffffff;
}

.dp-code-pre {
  margin: 0;
  padding: 1.25rem 1.5rem;
  overflow-x: auto;
  max-width: 100%;
  font-family: 'Fira Code', Menlo, Consolas, Monaco, monospace;
  font-size: 0.84rem;
  line-height: 1.6;
  color: #f8fafc;
  background: transparent;
  white-space: pre;
  -webkit-overflow-scrolling: touch;
}

/* Dynamic Line-by-Line Code Explanation */
.dp-explanation-card {
  margin-top: 1.25rem;
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  padding: 1rem 1.25rem;
}

.dp-explanation-title {
  font-size: 0.8125rem;
  font-weight: 700;
  color: #475569;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.75rem;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.dp-explanation-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.dp-explanation-item {
  font-size: 0.8125rem;
  color: #334155;
  line-height: 1.5;
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
}

.dp-explanation-item .material-symbols-outlined {
  color: #10b981;
  font-size: 16px;
  flex-shrink: 0;
  margin-top: 2px;
}

/* Complexity Cards */
.dp-complexity-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin-top: 0.75rem;
}

.dp-complexity-card {
  padding: 1rem;
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  border-radius: 8px;
}

.dp-complexity-label {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  color: #64748b;
  letter-spacing: 0.05em;
  margin-bottom: 0.25rem;
}

.dp-complexity-value {
  font-size: 1.25rem;
  font-weight: 800;
  font-family: var(--font-mono, monospace);
  margin-bottom: 0.25rem;
}

.dp-time-val { color: #4f46e5; }
.dp-space-val { color: #059669; }

.dp-complexity-desc {
  font-size: 0.75rem;
  color: #64748b;
  line-height: 1.4;
}

/* Mistakes and Takeaways */
.dp-mistakes-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.dp-mistake-item {
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
  font-size: 0.84rem;
  color: #334155;
  line-height: 1.5;
}

.dp-mistake-item .material-symbols-outlined {
  color: #ef4444;
  font-size: 16px;
  flex-shrink: 0;
  margin-top: 3px;
}

.dp-takeaway-box {
  background: #eef2ff;
  border: 1px solid #c7d2fe;
  border-radius: 8px;
  padding: 1rem 1.25rem;
  font-size: 0.875rem;
  color: #312e81;
  line-height: 1.6;
  font-weight: 500;
}

/* --------------------------------------------------------------------------
   6. Personal Notes Section
   -------------------------------------------------------------------------- */
.dp-notes-card {
  background: var(--color-surface, #ffffff);
  border: 1px solid var(--color-outline-variant, #e2e8f0);
  border-radius: var(--radius-lg, 12px);
  padding: 1.5rem;
  margin-top: 1.5rem;
}

.dp-notes-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.75rem;
}

.dp-notes-title {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1rem;
  font-weight: 700;
  color: #0f172a;
}

.dp-notes-status {
  font-size: 0.75rem;
  color: #94a3b8;
}

.dp-notes-textarea {
  width: 100%;
  min-height: 120px;
  padding: 0.875rem;
  font-size: 0.875rem;
  line-height: 1.5;
  border: 1px solid #cbd5e1;
  border-radius: 8px;
  background: #ffffff;
  color: #1e293b;
  resize: vertical;
  font-family: inherit;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.dp-notes-textarea:focus {
  outline: none;
  border-color: #6366f1;
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
}

/* --------------------------------------------------------------------------
   7. Contextual Previous / Next Navigation Bar
   -------------------------------------------------------------------------- */
.dp-nav-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid #e2e8f0;
}

.dp-nav-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.625rem 1.125rem;
  font-size: 0.84rem;
  font-weight: 700;
  background: #ffffff;
  color: #334155;
  border: 1px solid #cbd5e1;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s ease;
}

.dp-nav-btn:hover:not(:disabled) {
  background: #f8fafc;
  color: #4f46e5;
  border-color: #818cf8;
  transform: translateY(-1px);
}

.dp-nav-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

/* --------------------------------------------------------------------------
   8. Dedicated Revision Dashboard View
   -------------------------------------------------------------------------- */
.dp-revision-container {
  width: 100%;
  max-width: 1400px;
  margin: 0 auto;
}

.dp-revision-stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.dp-rev-stat-card {
  background: var(--color-surface, #ffffff);
  border: 1px solid var(--color-outline-variant, #e2e8f0);
  border-radius: 12px;
  padding: 1.25rem;
  display: flex;
  align-items: center;
  gap: 1rem;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.04);
}

.dp-rev-stat-icon {
  width: 44px;
  height: 44px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  flex-shrink: 0;
}

.dp-rev-stat-num {
  font-size: 1.5rem;
  font-weight: 800;
  color: #0f172a;
  line-height: 1.1;
  font-family: 'Plus Jakarta Sans', sans-serif;
}

.dp-rev-stat-label {
  font-size: 0.75rem;
  font-weight: 600;
  color: #64748b;
  margin-top: 2px;
}

/* Revision filter chips */
.dp-rev-chips {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

.dp-rev-chip {
  padding: 0.35rem 0.85rem;
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 600;
  background: #f1f5f9;
  color: #475569;
  border: 1px solid #cbd5e1;
  cursor: pointer;
  transition: all 0.15s ease;
}

.dp-rev-chip:hover {
  background: #e2e8f0;
}

.dp-rev-chip.active {
  background: #4f46e5;
  color: #ffffff;
  border-color: #4f46e5;
}

.dp-rev-chip-help30.active {
  background: #d97706;
  border-color: #d97706;
}

.dp-rev-chip-help50.active {
  background: #ea580c;
  border-color: #ea580c;
}

.dp-rev-chip-cross.active {
  background: #e11d48;
  border-color: #e11d48;
}

.dp-rev-row-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.dp-btn-re-rate {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  padding: 0.25rem 0.65rem;
  font-size: 0.75rem;
  font-weight: 600;
  color: #475569;
  background: #f8fafc;
  border: 1px solid #cbd5e1;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.15s ease;
}

.dp-btn-re-rate:hover {
  background: #f1f5f9;
  color: #0f172a;
  border-color: #94a3b8;
}

/* --------------------------------------------------------------------------
   9. Mobile & Tablet Responsiveness
   -------------------------------------------------------------------------- */
@media (max-width: 768px) {
  .dp-problem-title {
    font-size: 1.35rem;
  }

  .dp-header-card {
    padding: 1.25rem;
  }

  .dp-section-card {
    padding: 1.125rem;
  }

  .dp-actions-toolbar {
    width: 100%;
  }

  .dp-btn-action {
    flex: 1;
    justify-content: center;
  }

  .dp-nav-footer {
    flex-direction: column;
    width: 100%;
  }

  .dp-nav-btn {
    width: 100%;
    justify-content: center;
  }

  .dp-code-pre {
    font-size: 0.75rem;
    padding: 1rem;
  }
}

@keyframes dpFadeIn {
  from { opacity: 0; transform: translateY(-4px); }
  to { opacity: 1; transform: translateY(0); }
}