/* --- CSS Color Variables & Theme Definitions --- */
:root {
  --bg-body: #0f172a;
  --bg-card: #1e293b;
  --bg-subcard: #334155;
  --bg-inner: #0f172a;
  --text-main: #f8fafc;
  --text-sub: #94a3b8;
  --text-heading: #38bdf8;
  --border-color: #334155;
  --border-sub: #475569;
  --badge-warning: #f59e0b;
}

[data-theme="light"] {
  --bg-body: #f1f5f9;
  --bg-card: #ffffff;
  --bg-subcard: #f8fafc;
  --bg-inner: #f1f5f9;
  --text-main: #0f172a;
  --text-sub: #475569;
  --text-heading: #0284c7;
  --border-color: #cbd5e1;
  --border-sub: #cbd5e1;
  --badge-warning: #d97706;
}

/* --- Reset & Core Layout --- */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
}

body {
  background-color: var(--bg-body);
  color: var(--text-main);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 1rem;
  transition: background-color 0.3s ease, color 0.3s ease;
}

.app-container {
  width: 100%;
  max-width: 650px;
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 2rem;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
  position: relative;
  transition: background-color 0.3s ease, border-color 0.3s ease;
}

/* --- Utilities --- */
.hidden {
  display: none !important;
}

/* --- Top Bar & Theme Toggle Button --- */
.top-bar {
  display: flex;
  justify-content: flex-end;
  margin-bottom: 1rem;
}

.theme-btn {
  background-color: var(--bg-subcard);
  color: var(--text-main);
  border: 1px solid var(--border-sub);
  padding: 6px 14px;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: background-color 0.2s, transform 0.1s;
}

.theme-btn:hover {
  transform: scale(1.03);
}

/* --- Typography & Headings --- */
h1 {
  font-size: 1.8rem;
  margin-bottom: 0.75rem;
  color: var(--text-heading);
}

h2 {
  font-size: 1.4rem;
  margin-bottom: 1.25rem;
  color: var(--text-main);
}

p {
  color: var(--text-sub);
  margin-bottom: 1.5rem;
  line-height: 1.5;
}

/* --- Buttons --- */
.btn {
  display: inline-block;
  padding: 10px 18px;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: 8px;
  border: none;
  cursor: pointer;
  transition: background-color 0.2s ease, transform 0.1s ease;
}

.btn:active {
  transform: scale(0.98);
}

.primary-btn {
  background-color: #0284c7;
  color: #ffffff;
}

.primary-btn:hover {
  background-color: #0369a1;
}

.secondary-btn {
  background-color: #475569;
  color: #ffffff;
}

.secondary-btn:hover {
  background-color: #334155;
}

.warning-btn {
  background-color: #d97706;
  color: #ffffff;
}

.warning-btn:hover {
  background-color: #b45309;
}

.danger-btn {
  background-color: #ef4444;
  color: #ffffff;
}

.danger-btn:hover {
  background-color: #dc2626;
}

.back-btn {
  background-color: var(--bg-subcard);
  color: var(--text-main);
  border: 1px solid var(--border-sub);
  margin-bottom: 1rem;
}

.back-btn:hover {
  background-color: var(--border-sub);
}

.back-btn-warning {
  background-color: var(--bg-subcard);
  color: var(--text-main);
  border: 1px solid var(--border-sub);
  padding: 8px 14px;
  font-size: 0.85rem;
}

.back-btn-warning:hover {
  background-color: var(--border-sub);
}

/* --- Year Grid --- */
.year-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
  gap: 1rem;
}

.year-card {
  background-color: var(--bg-subcard);
  color: var(--text-main);
  padding: 1.5rem;
  border-radius: 8px;
  text-align: center;
  font-weight: bold;
  font-size: 1.1rem;
  cursor: pointer;
  border: 1px solid var(--border-sub);
  transition: border-color 0.2s, background-color 0.2s;
}

.year-card:hover {
  background-color: #0284c7;
  color: #ffffff;
  border-color: #38bdf8;
}

/* --- Subject List & Cards --- */
.subject-grid {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.subject-card {
  background-color: var(--bg-inner);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1.25rem;
}

.subject-card h3 {
  font-size: 1.1rem;
  color: var(--text-heading);
  margin-bottom: 0.5rem;
}

.missed-badge {
  color: var(--badge-warning);
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
}

.subject-actions {
  display: flex;
  gap: 0.75rem;
  margin-bottom: 0.5rem;
}

.study-btn {
  background-color: #0284c7;
  color: white;
  flex: 1;
}

.quiz-btn {
  background-color: #10b981;
  color: white;
  flex: 1;
}

.study-missed-btn {
  background-color: #d97706;
  color: #ffffff;
  width: 100%;
  margin-top: 6px;
}

.study-missed-btn:hover {
  background-color: #b45309;
}

.clear-btn {
  background-color: var(--bg-subcard);
  color: var(--text-sub);
  border: 1px solid var(--border-sub);
  width: 100%;
  margin-top: 6px;
  font-size: 0.8rem;
  padding: 6px;
}

.clear-btn:hover {
  background-color: #ef4444;
  color: white;
}

/* --- Quiz / Study Session Screen --- */
.quiz-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

.quiz-meta {
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--text-sub);
  margin-bottom: 1.25rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border-color);
}

.question-box h3 {
  font-size: 1.1rem;
  line-height: 1.5;
  margin-bottom: 1.25rem;
  color: var(--text-main);
}

.options-grid {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}

.option-btn {
  width: 100%;
  text-align: left;
  padding: 12px 16px;
  background-color: var(--bg-subcard);
  color: var(--text-main);
  border: 1px solid var(--border-sub);
  border-radius: 8px;
  font-size: 0.95rem;
  cursor: pointer;
  transition: background-color 0.2s, border-color 0.2s;
}

.option-btn:hover {
  background-color: var(--border-sub);
}

/* --- Results Screen --- */
.score-card {
  background-color: var(--bg-inner);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1.5rem;
  text-align: center;
  margin-bottom: 1.5rem;
}

.percentage-badge {
  font-size: 2.5rem;
  font-weight: bold;
  color: var(--text-heading);
  margin: 1rem 0;
}

.progress-bar-bg {
  width: 100%;
  height: 10px;
  background-color: var(--bg-subcard);
  border-radius: 5px;
  overflow: hidden;
}

.progress-bar-fill {
  height: 100%;
  width: 0%;
  background-color: #10b981;
  transition: width 0.6s ease-in-out;
}

/* --- Review Breakdown List --- */
.review-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  max-height: 350px;
  overflow-y: auto;
  margin-bottom: 1.5rem;
  padding-right: 0.5rem;
}

.review-card {
  background-color: var(--bg-inner);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1rem;
  text-align: left;
}

.review-card.correct {
  border-left: 5px solid #10b981;
}

.review-card.incorrect {
  border-left: 5px solid #ef4444;
}

.review-card h4 {
  font-size: 0.95rem;
  margin-bottom: 0.5rem;
  color: var(--text-main);
  line-height: 1.4;
}

.review-answer {
  font-size: 0.85rem;
  margin-bottom: 0.25rem;
}

.text-correct {
  color: #10b981;
}

.text-incorrect {
  color: #ef4444;
}

.result-actions {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

/* --- Custom Confirmation Modal Overlay --- */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background-color: rgba(15, 23, 42, 0.85);
  backdrop-filter: blur(4px);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 9999;
  padding: 1rem;
}

.modal-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.75rem;
  max-width: 420px;
  width: 100%;
  box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.5);
  text-align: center;
  animation: modalFadeIn 0.15s ease-out;
}

.modal-card h3 {
  font-size: 1.25rem;
  color: var(--text-main);
  margin-bottom: 0.75rem;
}

.modal-card p {
  font-size: 0.95rem;
  color: var(--text-sub);
  margin-bottom: 1.5rem;
}

.modal-actions {
  display: flex;
  justify-content: flex-end;
  gap: 0.75rem;
}

@keyframes modalFadeIn {
  from {
    opacity: 0;
    transform: scale(0.95);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}