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

:root {
    --primary-color: #1a472a;
    --secondary-color: #2d7a4a;
    --accent-color: #4db8a8;
    --danger-color: #d63031;
    --warning-color: #fdcb6e;
    --info-color: #00b4d8;
    --light-bg: #f8f9fa;
    --dark-text: #1a1a1a;
    --light-text: #f0f0f0;
    --border-color: #e0e0e0;
}

body {
    font-family: 'Poppins', sans-serif;
    background: linear-gradient(135deg, #0f2818 0%, #1a472a 50%, #0d1f14 100%);
    color: #f0f0f0;
    overflow-x: hidden;
    min-height: 100vh;
    position: relative;
}


/* MOLECULE BACKGROUND ANIMATION */
.molecule-background {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    opacity: 0.15;
}

.molecule {
    position: absolute;
    border: 2px solid rgba(77, 184, 168, 0.6);
    border-radius: 50%;
}

.mol-1 {
    width: 150px;
    height: 150px;
    top: 10%;
    left: 5%;
    animation: float 8s ease-in-out infinite;
}

.mol-2 {
    width: 200px;
    height: 200px;
    top: 60%;
    right: 10%;
    animation: float 10s ease-in-out infinite reverse;
}

.mol-3 {
    width: 100px;
    height: 100px;
    top: 30%;
    right: 20%;
    animation: float 12s ease-in-out infinite;
}

.mol-4 {
    width: 180px;
    height: 180px;
    bottom: 10%;
    left: 15%;
    animation: float 9s ease-in-out infinite reverse;
}

@keyframes float {
    0%, 100% {
        transform: translate(0, 0) rotate(0deg);
    }
    50% {
        transform: translate(30px, -30px) rotate(180deg);
    }
}

/* SCROLLBAR */
::-webkit-scrollbar {
    width: 12px;
}

::-webkit-scrollbar-thumb {
    background: linear-gradient(180deg, #4db8a8, #2d7a4a);
    border-radius: 10px;
}

::-webkit-scrollbar-track {
    background: rgba(26, 71, 42, 0.3);
}

/* INTRO SECTION */
.intro {
    height: 100vh;
    display: flex;
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
    padding: 40px 60px;
    transition: 0.8s ease;
    position: relative;
    z-index: 2;
    gap: 60px;
}

.intro.hide {
    opacity: 0;
    filter: blur(10px);
    transform: scale(0.95);
}

.intro-content {
    flex: 1;
    max-width: 900px;
}

.intro-title {
    font-family: 'Playfair Display', serif;
    font-size: 72px;
    font-weight: 800;
    color: #4db8a8;
    margin-bottom: 60px;
    text-shadow: 0 4px 15px rgba(77, 184, 168, 0.3);
    line-height: 1.1;
}

.intro-subtitle {
    font-size: 24px;
    color: #d0d0d0;
    margin-bottom: 15px;
    font-weight: 300;
    line-height: 1.4;
}

.intro-authors {
    font-size: 14px;
    color: #999;
    margin-bottom: 40px;
    letter-spacing: 1px;
}

.start-btn {
    padding: 16px 45px;
    font-size: 16px;
    font-weight: 600;
    border-radius: 50px;
    border: 2px solid #4db8a8;
    background: rgba(77, 184, 168, 0.1);
    color: #4db8a8;
    cursor: pointer;
    transition: 0.4s ease;
    backdrop-filter: blur(10px);
    letter-spacing: 1px;
}

.start-btn:hover {
    background: #4db8a8;
    color: #0f2818;
    box-shadow: 0 0 30px rgba(77, 184, 168, 0.6);
    transform: scale(1.05);
}

.intro-visual {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
}

.atom-orbit {
    position: relative;
    width: 250px;
    height: 250px;
}

.nucleus {
    position: absolute;
    width: 40px;
    height: 40px;
    background: radial-gradient(circle at 30% 30%, #4db8a8, #2d7a4a);
    border-radius: 50%;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    box-shadow: 0 0 30px rgba(77, 184, 168, 0.8);
}

.electron {
    position: absolute;
    width: 12px;
    height: 12px;
    background: #4db8a8;
    border-radius: 50%;
    box-shadow: 0 0 10px rgba(77, 184, 168, 0.8);
}

.electron-1 {
    animation: orbit 4s linear infinite;
}

.electron-2 {
    animation: orbit 5s linear infinite reverse;
    animation-delay: 1s;
}

.electron-3 {
    animation: orbit 6s linear infinite;
    animation-delay: 2s;
}

@keyframes orbit {
    0% {
        top: 50%;
        left: 50%;
        transform: translate(-50%, -50%) rotate(0deg) translateX(100px);
    }
    100% {
        top: 50%;
        left: 50%;
        transform: translate(-50%, -50%) rotate(360deg) translateX(100px);
    }
}

/* MENU */
.menu {
    display: none;
    min-height: 100vh;
    flex-direction: column;
    justify-content: flex-start;
    align-items: center;
    gap: 50px;
    padding: 80px 40px;
    animation: fadeUp 0.8s ease;
    position: relative;
    z-index: 2;
}

.menu-header {
    text-align: center;
    margin-bottom: 30px;
}

.menu-header h2 {
    font-family: 'Playfair Display', serif;
    font-size: 48px;
    color: #4db8a8;
    margin-bottom: 10px;
    text-shadow: 0 2px 10px rgba(77, 184, 168, 0.3);
}

.menu-header p {
    font-size: 18px;
    color: #b0b0b0;
}

/* CATEGORY SECTION */
.category-section {
    width: 100%;
    max-width: 1200px;
    margin-bottom: 40px;
}

.category-title {
    font-size: 28px;
    color: #4db8a8;
    margin-bottom: 30px;
    padding-bottom: 15px;
    border-bottom: 3px solid rgba(77, 184, 168, 0.3);
    text-transform: uppercase;
    letter-spacing: 2px;
    font-weight: 700;
}

/* CARD GRID */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 25px;
    width: 100%;
}

/* CARD */
.card {
    background: linear-gradient(135deg, rgba(45, 122, 74, 0.3) 0%, rgba(26, 71, 42, 0.2) 100%);
    border: 2px solid rgba(77, 184, 168, 0.3);
    border-radius: 20px;
    padding: 30px 25px;
    cursor: pointer;
    transition: 0.4s ease;
    position: relative;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.card::before {
    content: "";
    position: absolute;
    top: -50%;
    right: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(77, 184, 168, 0.2), transparent 70%);
    opacity: 0;
    transition: 0.4s ease;
}

.card:hover::before {
    opacity: 1;
}

.card:hover {
    transform: translateY(-8px);
    border-color: #4db8a8;
    background: linear-gradient(135deg, rgba(45, 122, 74, 0.5) 0%, rgba(26, 71, 42, 0.3) 100%);
    box-shadow: 0 15px 40px rgba(77, 184, 168, 0.3);
}

.card-header {
    display: flex;
    justify-content: center;
}

.card-icon {
    font-size: 48px;
    transition: 0.3s ease;
}

.card:hover .card-icon {
    transform: scale(1.2) rotate(10deg);
}

.card h4 {
    font-size: 20px;
    color: #4db8a8;
    font-weight: 700;
    text-shadow: 0 2px 8px rgba(77, 184, 168, 0.2);
    position: relative;
    z-index: 2;
}

.card p {
    font-size: 14px;
    color: #b0b0b0;
    position: relative;
    z-index: 2;
    line-height: 1.5;
}

.card-arrow {
    position: absolute;
    bottom: 20px;
    right: 20px;
    font-size: 24px;
    color: #4db8a8;
    opacity: 0;
    transition: 0.3s ease;
}

.card:hover .card-arrow {
    opacity: 1;
    transform: translateX(5px);
}

/* CONTENT PAGES */
.content {
    display: none;
    padding: 80px 60px;
    animation: fadeUp 0.8s ease;
    max-width: 1000px;
    margin: auto;
    position: relative;
    z-index: 2;
    min-height: 100vh;
}

.content-header {
    margin-bottom: 50px;
    position: relative;
    padding-bottom: 30px;
}

.header-accent {
    position: absolute;
    left: 0;
    top: 0;
    width: 5px;
    height: 60px;
    background: linear-gradient(180deg, #4db8a8, transparent);
    border-radius: 3px;
}

.content h2 {
    font-family: 'Playfair Display', serif;
    font-size: 52px;
    color: #4db8a8;
    margin-bottom: 15px;
    margin-left: 20px;
    text-shadow: 0 2px 10px rgba(77, 184, 168, 0.3);
    font-weight: 800;
}

.content-subtitle {
    font-size: 18px;
    color: #b0b0b0;
    margin-left: 20px;
    font-weight: 300;
}

.content-body {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.content p {
    font-size: 17px;
    line-height: 1.8;
    color: #d0d0d0;
    text-align: justify;
}

.content h4 {
    font-size: 22px;
    color: #4db8a8;
    margin-top: 20px;
    font-weight: 700;
    text-shadow: 0 2px 8px rgba(77, 184, 168, 0.2);
}

.content ul {
    margin: 15px 0 20px 30px;
    font-size: 16px;
    line-height: 1.9;
}

.content ul li {
    margin-bottom: 12px;
    color: #d0d0d0;
}

.content ul li::marker {
    color: #4db8a8;
}

/* INFO BOXES */
.info-box {
    background: linear-gradient(135deg, rgba(77, 184, 168, 0.15) 0%, rgba(45, 122, 74, 0.1) 100%);
    border-left: 5px solid #4db8a8;
    border-radius: 12px;
    padding: 25px;
    margin: 20px 0;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(77, 184, 168, 0.2);
    box-shadow: 0 4px 15px rgba(77, 184, 168, 0.1);
}

.info-box h4 {
    margin-top: 0;
    margin-bottom: 15px;
}

.info-box ul {
    margin-left: 20px;
}

.info-box.highlight {
    border-left-color: #fdcb6e;
    background: linear-gradient(135deg, rgba(253, 203, 110, 0.15) 0%, rgba(200, 150, 50, 0.1) 100%);
    border-color: rgba(253, 203, 110, 0.2);
}

.info-box.highlight h4 {
    color: #fdcb6e;
}

.effect-box {
    background: linear-gradient(135deg, rgba(0, 180, 216, 0.15) 0%, rgba(0, 150, 200, 0.1) 100%);
    border-left: 5px solid #00b4d8;
    border-radius: 12px;
    padding: 25px;
    margin: 20px 0;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(0, 180, 216, 0.2);
    box-shadow: 0 4px 15px rgba(0, 180, 216, 0.1);
}

.effect-box h4 {
    margin-top: 0;
    margin-bottom: 15px;
    color: #00b4d8;
}

.effect-box.highlight {
    border-left-color: #ff6b35;
    background: linear-gradient(135deg, rgba(255, 107, 53, 0.15) 0%, rgba(200, 100, 50, 0.1) 100%);
    border-color: rgba(255, 107, 53, 0.2);
}

.effect-box.highlight h4 {
    color: #ff6b35;
}

/* WARNING BOX */
.warning-box {
    background: linear-gradient(135deg, rgba(214, 48, 49, 0.15) 0%, rgba(200, 50, 80, 0.1) 100%);
    border-left: 5px solid #d63031;
    border-radius: 12px;
    padding: 25px;
    margin: 30px 0;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(214, 48, 49, 0.2);
    box-shadow: 0 4px 15px rgba(214, 48, 49, 0.15);
}

.warning-box h4 {
    margin-top: 0;
    margin-bottom: 15px;
    color: #d63031;
}

/* BACK BUTTON */
.back-btn {
    position: fixed;
    top: 30px;
    left: 30px;
    padding: 12px 30px;
    border-radius: 30px;
    border: 2px solid rgba(77, 184, 168, 0.6);
    background: rgba(77, 184, 168, 0.1);
    color: #4db8a8;
    cursor: pointer;
    display: none;
    transition: 0.3s ease;
    backdrop-filter: blur(10px);
    font-size: 16px;
    z-index: 5;
    font-weight: 600;
    font-family: 'Poppins', sans-serif;
}

.back-btn:hover {
    background: #4db8a8;
    color: #0f2818;
    box-shadow: 0 0 25px rgba(77, 184, 168, 0.8);
    transform: scale(1.08);
    border-color: #4db8a8;
}

/* QUIZ STYLES */
.quiz-container {
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
}

.quiz-question {
    display: block;
    animation: fadeUp 0.5s ease;
    margin-bottom: 40px;
}

.question-text {
    font-size: 22px;
    color: #4db8a8;
    margin-bottom: 30px;
    font-weight: 700;
    line-height: 1.5;
}

.options-container {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.option {
    display: flex;
    align-items: center;
    padding: 20px;
    background: linear-gradient(135deg, rgba(45, 122, 74, 0.2) 0%, rgba(26, 71, 42, 0.1) 100%);
    border: 2px solid rgba(77, 184, 168, 0.3);
    border-radius: 12px;
    cursor: pointer;
    transition: 0.3s ease;
    position: relative;
    overflow: hidden;
}

.option::before {
    content: "";
    position: absolute;
    top: -50%;
    right: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(77, 184, 168, 0.2), transparent 70%);
    opacity: 0;
    transition: 0.3s ease;
}

.option:hover {
    background: linear-gradient(135deg, rgba(45, 122, 74, 0.4) 0%, rgba(26, 71, 42, 0.2) 100%);
    border-color: #4db8a8;
    box-shadow: 0 8px 20px rgba(77, 184, 168, 0.2);
}

.option:hover::before {
    opacity: 1;
}

.option input[type="radio"] {
    width: 20px;
    height: 20px;
    margin-right: 15px;
    cursor: pointer;
    accent-color: #4db8a8;
}

.option-label {
    font-size: 16px;
    color: #d0d0d0;
    cursor: pointer;
    flex: 1;
    position: relative;
    z-index: 1;
}

.option input[type="radio"]:checked + .option-label {
    color: #4db8a8;
    font-weight: 600;
}

.option input[type="radio"]:checked {
    accent-color: #4db8a8;
}

/* CORRECT/INCORRECT STYLING */
.option-correct {
    background: linear-gradient(135deg, rgba(76, 175, 80, 0.3) 0%, rgba(56, 142, 60, 0.2) 100%) !important;
    border: 2px solid #4caf50 !important;
    box-shadow: 0 0 20px rgba(76, 175, 80, 0.3) !important;
}

.option-correct .option-label {
    color: #4caf50 !important;
}

.option-incorrect {
    background: linear-gradient(135deg, rgba(214, 48, 49, 0.3) 0%, rgba(200, 50, 80, 0.2) 100%) !important;
    border: 2px solid #d63031 !important;
    box-shadow: 0 0 20px rgba(214, 48, 49, 0.3) !important;
}

.option-incorrect .option-label {
    color: #ff6b6b !important;
}

/* ANSWER FEEDBACK */
.answer-feedback {
    display: none;
    margin-top: 12px;
    padding: 12px 15px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    animation: slideDown 0.3s ease;
}

.feedback-correct {
    color: #4caf50;
    background: rgba(76, 175, 80, 0.15);
    border-left: 4px solid #4caf50;
}

.feedback-incorrect {
    color: #ff6b6b;
    background: rgba(214, 48, 49, 0.15);
    border-left: 4px solid #d63031;
}

.feedback-unanswered {
    color: #fdcb6e;
    background: rgba(253, 203, 110, 0.15);
    border-left: 4px solid #fdcb6e;
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* VERIFY BUTTON */
.verify-btn {
    width: 100%;
    padding: 16px;
    margin-top: 30px;
    background: linear-gradient(135deg, #4db8a8, #00b4d8);
    border: none;
    color: #0f2818;
    font-weight: 700;
    font-size: 18px;
    border-radius: 12px;
    cursor: pointer;
    transition: 0.3s ease;
    font-family: 'Poppins', sans-serif;
}

.verify-btn:hover {
    background: linear-gradient(135deg, #00b4d8, #4db8a8);
    box-shadow: 0 0 30px rgba(77, 184, 168, 0.6);
    transform: translateY(-2px);
}

.verify-btn:active {
    transform: translateY(0);
}

/* QUIZ RESULTS */
.quiz-results {
    margin-top: 40px;
    padding: 30px;
    background: linear-gradient(135deg, rgba(77, 184, 168, 0.15) 0%, rgba(45, 122, 74, 0.1) 100%);
    border: 2px solid rgba(77, 184, 168, 0.3);
    border-radius: 15px;
    text-align: center;
    animation: fadeUp 0.5s ease;
}

.quiz-results h3 {
    font-size: 28px;
    color: #4db8a8;
    margin-bottom: 20px;
    font-weight: 700;
}

.score-display {
    margin: 30px 0;
}

.score-text {
    font-size: 24px;
    color: #d0d0d0;
    font-weight: 600;
    margin-bottom: 15px;
}

.score-text strong {
    color: #4db8a8;
    font-size: 32px;
}

.score-message {
    margin-top: 15px;
    padding: 15px;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
}

.score-message.perfect {
    background: rgba(76, 175, 80, 0.2);
    color: #4caf50;
    border: 1px solid rgba(76, 175, 80, 0.3);
}

.score-message.excellent {
    background: rgba(0, 180, 216, 0.2);
    color: #00b4d8;
    border: 1px solid rgba(0, 180, 216, 0.3);
}

.score-message.good {
    background: rgba(253, 203, 110, 0.2);
    color: #fdcb6e;
    border: 1px solid rgba(253, 203, 110, 0.3);
}

.score-message.fair {
    background: rgba(255, 107, 53, 0.2);
    color: #ff6b35;
    border: 1px solid rgba(255, 107, 53, 0.3);
}

/* RESET BUTTON */
.reset-btn {
    width: 100%;
    padding: 14px;
    margin-top: 20px;
    background: rgba(77, 184, 168, 0.2);
    border: 2px solid #4db8a8;
    color: #4db8a8;
    font-weight: 600;
    font-size: 16px;
    border-radius: 12px;
    cursor: pointer;
    transition: 0.3s ease;
    font-family: 'Poppins', sans-serif;
}

.reset-btn:hover {
    background: #4db8a8;
    color: #0f2818;
    box-shadow: 0 0 20px rgba(77, 184, 168, 0.5);
}

/* ANIMATIONS */
@keyframes fadeUp {
    from {
        opacity: 0;
        transform: translateY(40px);
        filter: blur(8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
        filter: blur(0);
    }
}

/* RESPONSIVE */
@media (max-width: 1024px) {
    .intro {
        flex-direction: column;
        padding: 40px 30px;
        gap: 40px;
    }

    .intro-title {
        font-size: 52px;
    }

    .intro-subtitle {
        font-size: 20px;
    }

    .atom-orbit {
        width: 200px;
        height: 200px;
    }

    .model-container {
        min-height: 500px;
        padding: 30px 15px;
    }

    .model-container model-viewer {
        height: 500px;
        max-width: 900px;
    }

    .content {
        padding: 60px 40px;
    }

    .content h2 {
        font-size: 40px;
    }

    .card-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .intro-title {
        font-size: 40px;
    }

    .intro-subtitle {
        font-size: 18px;
    }

    .menu-header h2 {
        font-size: 36px;
    }

    .category-title {
        font-size: 22px;
    }

    .model-container {
        min-height: 400px;
        padding: 25px 15px;
    }

    .model-container model-viewer {
        height: 400px;
        max-width: 100%;
    }

    .content {
        padding: 40px 20px;
    }

    .content h2 {
        font-size: 32px;
    }

    .content p {
        font-size: 16px;
    }

    .back-btn {
        top: 20px;
        left: 20px;
        padding: 10px 20px;
        font-size: 14px;
    }

    .menu {
        padding: 60px 20px;
        gap: 30px;
    }

    .question-text {
        font-size: 18px;
    }

    .option {
        padding: 15px;
    }

    .option input[type="radio"] {
        width: 18px;
        height: 18px;
    }

    .option-label {
        font-size: 14px;
    }

    .verify-btn {
        font-size: 16px;
        padding: 14px;
    }

    .quiz-results h3 {
        font-size: 24px;
    }

    .score-text {
        font-size: 20px;
    }

    .score-text strong {
        font-size: 28px;
    }
}

@media (max-width: 480px) {
    .intro {
        padding: 30px 20px;
    }

    .intro-title {
        font-size: 32px;
    }

    .intro-subtitle {
        font-size: 16px;
    }

    .start-btn {
        padding: 12px 30px;
        font-size: 14px;
    }

    .menu-header h2 {
        font-size: 28px;
    }

    .category-title {
        font-size: 18px;
    }

    .card {
        padding: 20px 15px;
    }

    .card h4 {
        font-size: 18px;
    }

    .card p {
        font-size: 13px;
    }

    .model-container {
        min-height: 300px;
        padding: 20px 10px;
    }

    .model-container model-viewer {
        height: 300px;
        max-width: 100%;
    }

    .content h2 {
        font-size: 28px;
    }

    .content p {
        font-size: 15px;
        text-align: left;
    }

    .content ul {
        margin-left: 20px;
        font-size: 15px;
    }

    .info-box,
    .effect-box,
    .warning-box {
        padding: 15px;
    }

    .question-text {
        font-size: 16px;
    }

    .option {
        padding: 12px;
    }

    .option input[type="radio"] {
        width: 16px;
        height: 16px;
    }

    .option-label {
        font-size: 13px;
    }

    .verify-btn {
        font-size: 14px;
        padding: 12px;
    }

    .quiz-results {
        padding: 20px;
    }

    .quiz-results h3 {
        font-size: 20px;
    }

    .score-text {
        font-size: 16px;
    }

    .score-text strong {
        font-size: 24px;
    }

    .answer-feedback {
        font-size: 12px;
    }
}