:root {
    --alkali-metal-bg: #DBF8FF;
    --alkali-metal-text: #00758C;
    --alkaline-earth-metal-bg: #FFEBEB;
    --alkaline-earth-metal-text: #D60024;
    --transition-metal-bg: #F5ECFD;
    --transition-metal-text: #784EEF;
    --post-transition-metal-bg: #DCFAEB;
    --post-transition-metal-text: #002C00;
    --metalloid-bg: #FEF9E6;
    --metalloid-text: #9A610E;
    --reactive-nonmetal-bg: #E6F0FF;
    --reactive-nonmetal-text: #0060F0; 
    --noble-gas-bg: #FFEBEE;
    --noble-gas-text: #CD1D5E;
    --lanthanide-bg: #E6F5FF;
    --lanthanide-text: #003355;
    --actinide-bg: #FFEADB;
    --actinide-text: #C73200;
    --unknown-bg: #e0e0e0;
    --unknown-text: #333333;
    --sidebar-width: 500px;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

body {
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    font-family: 'Inter', sans-serif;
    padding-top: 56px;
    display: flex;
    flex-direction: column;
    transition: padding-right 0.4s cubic-bezier(0.25, 0.8, 0.25, 1);
}

body.sidebar-open {
    padding-right: var(--sidebar-width) !important;
}

.offcanvas.offcanvas-end {
    width: var(--sidebar-width);
    font-size: 18px;
}

main.container-fluid {
    width: 100%;
    max-width: 1400px;
    margin: 0 auto;
    padding-left: 1rem;
    padding-right: 1rem;
}

.periodic-table-container {
    overflow-x: auto;
    padding: 1.5rem;
    background-color: rgba(255, 255, 255, 0.7);
    backdrop-filter: blur(10px);
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
    min-width: 0;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.periodic-table-grid {
    display: grid;
    grid-template-columns: repeat(18, 68px);
    grid-template-rows: repeat(7, 68px);
    gap: 5px;
    min-width: calc(18 * 68px + 17 * 5px);
}

.element-card {
    width: 68px;
    height: 68px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    padding: 5px;
    border: 1px solid transparent;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
    text-align: left;
    font-weight: 500;
    animation: fadeIn 0.5s ease-out forwards;
    opacity: 0;
    animation-fill-mode: both;
}

.element-card:hover {
    transform: scale(1.08);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.12);
    border-color: rgba(0, 0, 0, 0.1);
}

.element-card.selected {
    border-width: 1.5px;
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.15);
}

.element-card.selected.alkali-metal {
    border-color: var(--alkali-metal-text);
}

.element-card.selected.alkaline-earth-metal {
    border-color: var(--alkaline-earth-metal-text);
}

.element-card.selected.transition-metal {
    border-color: var(--transition-metal-text);
}

.element-card.selected.post-transition-metal {
    border-color: var(--post-transition-metal-text);
}

.element-card.selected.metalloid {
    border-color: var(--metalloid-text);
}

.element-card.selected.reactive-nonmetal {
    border-color: var(--reactive-nonmetal-text);
}

.element-card.selected.noble-gas {
    border-color: var(--noble-gas-text);
}

.element-card.selected.lanthanide {
    border-color: var(--lanthanide-text);
}

.element-card.selected.actinide {
    border-color: var(--actinide-text);
}

.element-card.selected.unknown {
    border-color: var(--unknown-text);
}

.element-card.selected:hover {
    transform: scale(1.05);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.2);
}

.element-number {
    font-size: 0.65rem;
    opacity: 0.7;
    align-self: flex-start;
}

.element-symbol {
    font-weight: 700;
    font-size: 1.1rem;
    text-align: center;
    line-height: 1;
}

.element-name {
    font-size: 0.55rem;
    text-align: center;
    line-height: 1;
    align-self: center;
    width: 100%;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

/* Category colors */
.alkali-metal {
    background-color: var(--alkali-metal-bg);
    color: var(--alkali-metal-text);
}

.alkaline-earth-metal {
    background-color: var(--alkaline-earth-metal-bg);
    color: var(--alkaline-earth-metal-text);
}

.transition-metal {
    background-color: var(--transition-metal-bg);
    color: var(--transition-metal-text);
}

.post-transition-metal {
    background-color: var(--post-transition-metal-bg);
    color: var(--post-transition-metal-text);
}

.metalloid {
    background-color: var(--metalloid-bg);
    color: var(--metalloid-text);
}

.reactive-nonmetal {
    background-color: var(--reactive-nonmetal-bg);
    color: var(--reactive-nonmetal-text);
}

.noble-gas {
    background-color: var(--noble-gas-bg);
    color: var(--noble-gas-text);
}

.lanthanide {
    background-color: var(--lanthanide-bg);
    color: var(--lanthanide-text);
}

.actinide {
    background-color: var(--actinide-bg);
    color: var(--actinide-text);
}

.unknown {
    background-color: var(--unknown-bg);
    color: var(--unknown-text);
}

.legend-card {
    background-color: rgba(255, 255, 255, 0.7);
    backdrop-filter: blur(10px);
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.85rem;
}

.legend-color-box {
    width: 20px;
    height: 20px;
    border-radius: 4px;
    border: 1px solid rgba(0, 0, 0, 0.1);
}

.offcanvas {
    width: var(--sidebar-width);
    border-top-left-radius: 12px;
    border-bottom-left-radius: 12px;
    box-shadow: -4px 0 25px rgba(0, 0, 0, 0.15);
    background-color: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    transition: transform 0.4s cubic-bezier(0.25, 0.8, 0.25, 1);
}

@media (max-width: 768px) {
    body.sidebar-open {
        padding-right: 0;
    }

    .offcanvas {
        width: 100%;
    }
}

.btn {
    transition: all 0.3s ease;
}

.chat-bubble-user {
    background-color: #0d6efd;
    color: white;
    border-radius: 1.1rem 1.1rem 0.25rem 1.1rem;
    padding: 0.6rem 1.1rem;
    margin-bottom: 0.5rem;
    max-width: 85%;
    align-self: flex-end;
    line-height: 1.5;
    animation: fadeIn 0.3s ease-out;
}

.chat-bubble-bot {
    background-color: #e9ecef;
    color: #212529;
    border-radius: 1.1rem 1.1rem 1.1rem 0.25rem;
    padding: 0.6rem 1.1rem;
    margin-bottom: 0.5rem;
    max-width: 100%;
    align-self: flex-start;
    line-height: 1.5;
    word-break: break-word;
    animation: fadeIn 0.3s ease-out;
}

.chat-bubble-bot ul,
.chat-bubble-bot ol {
    padding-left: 1.2rem;
    margin-bottom: 0.5rem;
    margin-top: 0.5rem;
}

.chat-bubble-bot li {
    margin-bottom: 0.25rem;
}

.chat-bubble-bot pre {
    background-color: #282c34;
    color: #abb2bf;
    padding: 0.75rem;
    border-radius: 6px;
    overflow-x: auto;
    font-size: 0.875rem;
    margin: 0.75rem 0;
}

.chat-bubble-bot code {
    background-color: rgba(0, 0, 0, 0.08);
    padding: 0.2em 0.4em;
    border-radius: 4px;
    font-size: 0.875em;
}

.chat-bubble-bot pre code {
    background-color: transparent;
    padding: 0;
    font-size: inherit;
}

.chat-bubble-bot blockquote {
    border-left: 4px solid #0d6efd;
    padding-left: 0.75rem;
    margin: 0.75rem 0;
    color: #495057;
    font-style: italic;
}

.chat-bubble-bot table {
    width: 100%;
    border-collapse: collapse;
    margin: 0.75rem 0;
    font-size: 0.9rem;
}

.chat-bubble-bot th,
.chat-bubble-bot td {
    border: 1px solid #dee2e6;
    padding: 0.4rem 0.6rem;
}

.chat-bubble-bot th {
    background-color: #f1f3f5;
}

#chat-history {
    overflow-y: auto;
    padding-right: 10px;
}

.quiz-option {
    border: 2px solid #dee2e6;
    border-radius: 8px;
    padding: 0.75rem 1rem;
    margin-bottom: 0.75rem;
    cursor: pointer;
    transition: all 0.25s ease-in-out;
    font-weight: 500;
}

.quiz-option:hover {
    border-color: #0d6efd;
    background-color: #f0f6ff;
    transform: translateY(-3px);
    box-shadow: 0 4px 12px rgba(13, 110, 253, 0.1);
}

.quiz-option.correct {
    border-color: #198754;
    background-color: #d1e7dd;
    color: #0f5132;
    transform: scale(1.02);
}

.quiz-option.incorrect {
    border-color: #dc3545;
    background-color: #f8d7da;
    color: #58151c;
    animation: shake 0.5s;
}

@keyframes shake {

    0%,
    100% {
        transform: translateX(0);
    }

    25% {
        transform: translateX(-5px);
    }

    75% {
        transform: translateX(5px);
    }
}

.loading-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(255, 255, 255, 0.85);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    border-radius: 12px;
    backdrop-filter: blur(4px);
}

model-viewer {
    width: 100%;
    height: 300px;
    border-radius: 8px;
}

.tab-content>div {
    display: none;
}

.tab-content>div.active {
    display: block;
}

.navbar {
    background-image: linear-gradient(120deg, #a6c0fe 0%, #f68084 100%);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
    border-bottom: 1px solid rgba(255, 255, 255, 0.2);
}

footer {
    background-image: linear-gradient(120deg, #a6c0fe 0%, #f68084 100%);
}

.help-container {
    position: fixed;
    bottom: 20px;
    right: 20px;
    z-index: 1030;
    transition: right 0.4s cubic-bezier(0.25, 0.8, 0.25, 1);
}

body.sidebar-open .help-container {
    right: calc(var(--sidebar-width) + 20px);
}

@media (max-width: 768px) {
    body.sidebar-open .help-container {
        right: 20px;
    }
}

.help-fab {
    width: 56px;
    height: 56px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
    background-image: linear-gradient(120deg, #a6c0fe 0%, #f68084 100%);
    border: none;
}