:root {
  --bg-color: #f1f7f9; /* Lab-coat tint */
  --card-bg: #ffffff;
  --text-main: #2d3436;
  --text-dim: #636e72;
  --accent-primary: #00b894; /* Emerald Lab */
  --accent-wrong: #ff7675; /* Reactive Red */
  --accent-noble: #6c5ce7; /* Noble Purple */
  --accent-metal: #0984e3; /* Industrial Blue */
  --gold: #d4af37;
  --shadow: 0 10px 40px rgba(0,0,0,0.06);
  --border-radius: 28px;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'Outfit', sans-serif;
  background-color: var(--bg-color);
  background-image: radial-gradient(#d1e1e4 1px, transparent 1px);
  background-size: 30px 30px; /* Periodic table grid hint */
  color: var(--text-main);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 20px;
}

#app-container {
  width: 100%;
  max-width: 600px;
  display: flex;
  flex-direction: column;
  gap: 30px;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-weight: 800;
  letter-spacing: 6px;
  font-size: 1.4rem;
  color: #2d3436;
}

#stats {
  display: flex;
  gap: 20px;
  font-weight: 700;
  font-size: 0.9rem;
}

.mode-nav {
    display: flex;
    gap: 10px;
}

.mode-btn {
    background: #fff;
    border: 1.5px solid #eee;
    padding: 8px 16px;
    border-radius: 12px;
    font-family: inherit;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.2s;
    font-size: 0.85rem;
}

.mode-btn.active {
    background: var(--text-main);
    color: white;
    border-color: var(--text-main);
}

.stat-item span {
  color: var(--accent-metal);
}

/* Card Design */
.card {
  background: var(--card-bg);
  padding: 60px 40px;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow);
  text-align: center;
  border: 1px solid rgba(0,0,0,0.02);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: "ATOM";
  position: absolute;
  top: -20px;
  right: -20px;
  font-size: 5rem;
  font-weight: 900;
  opacity: 0.03;
}

.meta-row {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 15px;
  margin-bottom: 30px;
}

.tag {
  color: var(--text-dim);
  padding: 6px 14px;
  border-radius: 100px;
  font-size: 0.8rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 1px;
}

#atomic-number {
  background: #dfe6e9; /* Light metal */
}

.type-noble { background: #efecfd; color: var(--accent-noble); }
.type-metal { background: #e3f2fd; color: var(--accent-metal); }
.type-gas { background: #e8f5e9; color: var(--accent-primary); }

.symbol-display {
  font-family: 'Playfair Display', serif;
  font-size: 8rem;
  font-weight: 800;
  margin-bottom: 20px;
  background: linear-gradient(135deg, #2d3436, #636e72);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  line-height: 1;
}

h2 {
  font-family: 'Outfit', sans-serif;
  font-size: 1.35rem;
  margin-bottom: 35px;
  color: var(--text-dim);
  font-weight: 400;
}

/* Options */
#options-container {
  display: flex;
  flex-direction: column;
  gap: 15px;
}

.option-btn {
  background: #fdfdfd;
  border: 2px solid #f1f2f6;
  padding: 22px;
  border-radius: 20px;
  font-family: inherit;
  font-size: 1.25rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.25s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  color: var(--text-main);
  text-align: center;
}

.option-btn:hover {
  background: #fdfdfd;
  border-color: var(--accent-metal);
  transform: translateY(-4px);
  box-shadow: 0 8px 20px rgba(0,0,0,0.04);
}

.option-btn.correct {
  background: rgba(0, 184, 148, 0.08);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}

.option-btn.wrong {
  background: rgba(255, 118, 117, 0.08);
  border-color: var(--accent-wrong);
  color: var(--accent-wrong);
}

.option-btn.disabled {
  pointer-events: none;
  opacity: 0.6;
}

/* Feedback Box */
#feedback {
  margin-top: 45px;
  padding-top: 35px;
  border-top: 1px solid #f1f2f6;
  text-align: left;
  animation: slideUp 0.5s ease;
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

#feedback-message {
  font-weight: 900;
  font-size: 1.5rem;
  display: block;
  margin-bottom: 20px;
  text-align: center;
}

.helper {
  background: #f8fafb;
  padding: 24px;
  border-radius: 18px;
  font-size: 1.05rem;
  color: #4b5563;
  margin-bottom: 30px;
}

.helper strong {
  display: block;
  color: #1f2937;
  margin-bottom: 8px;
  letter-spacing: 0.5px;
}

#next-btn {
  width: 100%;
  padding: 22px;
  background: #1f2937;
  color: white;
  border: none;
  border-radius: 20px;
  font-family: inherit;
  font-weight: 700;
  font-size: 1.25rem;
  cursor: pointer;
  transition: all 0.2s;
}

#next-btn:hover {
  background: #000;
  transform: scale(1.01);
}

.hidden {
  display: none !important;
}

/* Footer */
footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.9rem;
  color: var(--text-dim);
  font-weight: 600;
}

#reset-btn {
  background: none;
  border: none;
  color: var(--text-dim);
  font-weight: 800;
  cursor: pointer;
  text-decoration: underline;
  text-underline-offset: 4px;
}

.footer-links {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    margin-bottom: 10px;
}

.db-nav {
    display: flex;
    gap: 20px;
}

.db-link {
    color: var(--accent-metal);
    text-decoration: none;
    font-weight: 800;
}

@media (max-width: 480px) {
  .card {
    padding: 40px 25px;
  }
  .symbol-display {
    font-size: 6rem;
  }
}

/* Synthesis Specifics */
.lab-card {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.lab-desc {
    margin-bottom: 30px;
}

#beaker {
    width: 180px;
    height: 220px;
    border: 6px solid #e1e8ed;
    border-top: none;
    border-radius: 0 0 40px 40px;
    position: relative;
    margin-bottom: 40px;
    background: rgba(255,255,255,0.5);
    overflow: hidden;
}

.beaker-liquid {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 30%;
    background: rgba(0, 184, 148, 0.1);
    transition: height 0.5s ease;
}

#beaker-contents {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    justify-content: center;
    padding: 20px;
    position: relative;
    z-index: 2;
}

.beaker-atom {
    background: var(--accent-metal);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    transition: width 0.3s ease, height 0.3s ease, font-size 0.3s ease;
    animation: dropIn 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    flex-shrink: 0;
}

@keyframes dropIn {
    from { transform: translateY(-100px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

.bonded-atom {
    background: var(--accent-primary) !important;
    border: 2px solid rgba(255,255,255,0.5);
    box-shadow: 0 0 0 2px var(--accent-primary), 0 4px 12px rgba(0,184,148,0.35);
    cursor: pointer;
    animation: bondPop 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

@keyframes bondPop {
    0%   { transform: scale(1); }
    40%  { transform: scale(1.3); }
    100% { transform: scale(1); }
}

#search-lab-container {
    width: 100%;
    margin-bottom: 30px;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.search-box {
    position: relative;
    width: 100%;
}

#element-search-input {
    width: 100%;
    padding: 16px 20px;
    border-radius: 18px;
    border: 2px solid #edf2f4;
    background: #fff;
    font-family: inherit;
    font-size: 1rem;
    font-weight: 600;
    transition: all 0.3s;
    outline: none;
}

#element-search-input:focus {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 4px rgba(0, 184, 148, 0.1);
}

#search-results {
    position: absolute;
    top: calc(100% + 8px);
    left: 0;
    width: 100%;
    background: white;
    border-radius: 20px;
    box-shadow: 0 15px 40px rgba(0,0,0,0.12);
    z-index: 100;
    max-height: 250px;
    overflow-y: auto;
    border: 1px solid #edf2f4;
    padding: 10px;
}

.search-result-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 18px;
    border-radius: 12px;
    cursor: pointer;
    transition: background 0.2s;
}

.search-result-item:hover {
    background: #f8fafb;
}

.search-result-item .symbol {
    font-weight: 800;
    color: var(--accent-metal);
    font-size: 1.1rem;
}

.search-result-item .name {
    font-weight: 500;
    color: var(--text-dim);
    flex: 1;
    padding: 0 10px;
}

.search-section-header {
    padding: 8px 18px 4px;
    font-size: 0.7rem;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    color: #aaa;
    border-top: 1px solid #f1f2f6;
    margin-top: 4px;
}

.search-section-header:first-child {
    border-top: none;
    margin-top: 0;
}

.result-type-tag {
    font-size: 0.7rem;
    font-weight: 700;
    padding: 3px 8px;
    border-radius: 8px;
    white-space: nowrap;
}

.element-tag {
    background: #e3f2fd;
    color: var(--accent-metal);
}

.compound-tag {
    background: #f3e8ff;
    color: var(--accent-noble);
    max-width: 140px;
    overflow: hidden;
    text-overflow: ellipsis;
}

.compound-formula {
    font-weight: 800;
    color: var(--accent-primary);
    font-size: 1rem;
    min-width: 50px;
}

.compound-result-item {
    background: rgba(108, 92, 231, 0.02);
}

.compound-result-item:hover {
    background: rgba(108, 92, 231, 0.06) !important;
}


.custom-slots {
    display: flex;
    gap: 12px;
    justify-content: center;
}

.slot-btn {
    flex: 1;
    height: 70px;
    background: #fdfdfd;
    border: 2px dashed #ddd;
    border-radius: 15px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.2s;
    position: relative;
}

#search-results::-webkit-scrollbar {
    width: 6px;
}

#search-results::-webkit-scrollbar-track {
    background: transparent;
}

#search-results::-webkit-scrollbar-thumb {
    background: #e1e8ed;
    border-radius: 10px;
}

#search-results::-webkit-scrollbar-thumb:hover {
    background: #d1d9e0;
}

.slot-btn.active {
    border-style: solid;
    border-color: var(--accent-noble);
    background: rgba(108, 92, 231, 0.03);
    animation: activePulse 2s infinite;
}

@keyframes activePulse {
    0% { box-shadow: 0 0 0 0 rgba(108, 92, 231, 0.4); }
    70% { box-shadow: 0 0 0 10px rgba(108, 92, 231, 0); }
    100% { box-shadow: 0 0 0 0 rgba(108, 92, 231, 0); }
}

.slot-btn span {
    font-size: 10px;
    text-transform: uppercase;
    font-weight: 800;
    color: #999;
    margin-top: 4px;
}

.slot-btn.occupied {
    border-style: solid;
    border-color: var(--accent-metal);
}

.slot-btn.occupied span {
    color: var(--text-dim);
}

.slot-symbol {
    font-size: 1.4rem;
    font-weight: 800;
    color: var(--text-main);
}

#element-shelf {
    display: flex;
    gap: 12px;
    margin-bottom: 40px;
    flex-wrap: wrap;
    justify-content: center;
}

.shelf-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 10px;
    background: white;
    border: 2px solid #eee;
    border-radius: 15px;
    cursor: pointer;
    min-width: 65px;
    transition: all 0.2s;
    font-family: inherit;
    font-weight: 800;
    font-size: 1.1rem;
    color: var(--text-main);
}

.shelf-btn:hover {
    border-color: var(--accent-metal);
    transform: translateY(-2px);
}

.shelf-btn span {
    font-size: 10px;
    text-transform: uppercase;
    font-weight: 700;
    color: var(--text-dim);
}

.lab-actions {
    display: flex;
    gap: 15px;
    width: 100%;
}

.lab-actions button {
    flex: 1;
    padding: 18px;
    border-radius: 15px;
    border: none;
    font-family: inherit;
    font-weight: 700;
    cursor: pointer;
}

.primary-action {
    background: var(--accent-primary);
    color: white;
}

.secondary-action {
    background: #f1f2f6;
    color: var(--text-main);
}

#clear-beaker {
    background: #fff;
    border: 2px solid #eee !important;
    color: var(--text-dim);
}

/* Modal Overlay */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.4);
    backdrop-filter: blur(5px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.modal-card {
    background: white;
    width: 90%;
    max-width: 450px;
    padding: 35px;
    border-radius: 30px;
    box-shadow: 0 20px 50px rgba(0,0,0,0.15);
    position: relative;
    max-height: 80vh;
    overflow-y: auto;
}

#close-recipes {
    position: absolute;
    top: 20px;
    right: 20px;
    border: none;
    background: #f1f2f6;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    font-size: 20px;
    cursor: pointer;
}

#recipe-list {
    margin-top: 20px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.recipe-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px;
    background: #f9fbfb;
    border-radius: 15px;
    border: 1px solid #edf2f4;
}

.recipe-info h4 {
    margin: 0;
    font-size: 1.05rem;
}

.recipe-info p {
    margin: 4px 0 0;
    font-size: 0.85rem;
    color: var(--text-dim);
}

.recipe-formula {
    background: var(--text-main);
    color: white;
    padding: 4px 10px;
    border-radius: 8px;
    font-weight: 800;
    font-size: 0.9rem;
    font-family: 'Playfair Display', serif;
}

/* Random Compound Button */
.random-action {
    background: linear-gradient(135deg, #6c5ce7, #a29bfe);
    color: white;
    border: none;
    font-family: inherit;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.2s;
    letter-spacing: 0.3px;
}

.random-action:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(108, 92, 231, 0.4);
}

.random-action:disabled {
    opacity: 0.7;
    transform: none;
    cursor: wait;
}

/* Random Fact Toast */
#random-toast {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%) translateY(0);
    background: #1f2937;
    color: white;
    padding: 16px 22px;
    border-radius: 20px;
    display: flex;
    align-items: center;
    gap: 14px;
    box-shadow: 0 20px 50px rgba(0,0,0,0.25);
    z-index: 9999;
    max-width: 420px;
    width: 90%;
    animation: toastIn 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.toast-emoji {
    font-size: 2rem;
    flex-shrink: 0;
}

.toast-body {
    display: flex;
    flex-direction: column;
    gap: 3px;
}

.toast-body strong {
    font-size: 1rem;
    font-weight: 800;
}

.toast-body span {
    font-size: 0.82rem;
    color: #9ca3af;
    line-height: 1.4;
}

@keyframes toastIn {
    from { opacity: 0; transform: translateX(-50%) translateY(30px); }
    to   { opacity: 1; transform: translateX(-50%) translateY(0); }
}

#random-toast.toast-out {
    animation: toastOut 0.5s ease forwards;
}

@keyframes toastOut {
    to { opacity: 0; transform: translateX(-50%) translateY(20px); }
}