* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', sans-serif;
    scroll-behavior: smooth;
}

body {
    background: #f5faf6;
    color: #183b2b;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 22px 8%;
    background: white;
    box-shadow: 0 3px 20px #0000000a;
    position: sticky;
    top: 0;
    z-index: 100;
}

.logo {
    font-size: 25px;
    font-weight: bold;
    color: #16834a;
}

nav a {
    text-decoration: none;
    color: #244b36;
    margin-left: 25px;
    font-weight: 600;
    transition: 0.3s;
}

nav a:hover {
    color: #20a65b;
}

.hero {
    min-height: 540px;
    padding: 100px 10%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: linear-gradient(120deg, #e1f6e8, #f8fff9);
}

.hero-content {
    max-width: 600px;
}

.tag {
    color: #159653;
    font-weight: bold;
    letter-spacing: 2px;
    margin-bottom: 20px;
}

.hero h1 {
    font-size: 55px;
    line-height: 1.2;
    margin-bottom: 20px;
}

.hero h1 span {
    color: #159653;
}

.hero-content > p:not(.tag) {
    font-size: 18px;
    line-height: 1.8;
    color: #607567;
}

.btn {
    display: inline-block;
    margin-top: 30px;
    padding: 15px 28px;
    background: #159653;
    color: white;
    border-radius: 30px;
    text-decoration: none;
    transition: 0.3s;
}

.btn:hover {
    background: #0c6738;
    transform: translateY(-4px);
}

.hero-icon {
    font-size: 150px;
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    50% {
        transform: translateY(-18px);
    }
}

.about, .cards, .quiz {
    padding: 80px 10%;
    text-align: center;
}

h2 {
    font-size: 35px;
    margin-bottom: 25px;
}

.about > p:last-child {
    max-width: 700px;
    margin: auto;
    line-height: 1.8;
    color: #607567;
}

.card-container {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 22px;
    margin-top: 45px;
}

.card {
    background: white;
    padding: 35px 20px;
    border-radius: 20px;
    box-shadow: 0 8px 30px #183b2b0c;
    transition: 0.3s;
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 35px #15965325;
}

.card span {
    font-size: 45px;
}

.card h3 {
    margin: 20px 0 12px;
    color: #159653;
}

.card p {
    color: #68796d;
    line-height: 1.6;
}

.quiz {
    background: #e5f5e9;
}

.quiz p {
    margin-bottom: 20px;
}

.quiz button {
    background: #159653;
    color: white;
    border: none;
    padding: 15px 35px;
    border-radius: 30px;
    font-size: 16px;
    cursor: pointer;
}

#quiz-result {
    margin-top: 25px;
    font-weight: bold;
}

footer {
    background: #123d29;
    color: white;
    text-align: center;
    padding: 35px;
    line-height: 2;
}

@media (max-width: 800px) {
    header {
        flex-direction: column;
        gap: 20px;
    }

    nav a {
        margin: 8px;
        font-size: 13px;
    }

    .hero {
        flex-direction: column;
        text-align: center;
        gap: 40px;
    }

    .hero h1 {
        font-size: 38px;
    }

    .card-container {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 480px) {
    .card-container {
        grid-template-columns: 1fr;
    }
}

.impact {
    padding: 80px 10%;
    text-align: center;
    background: #f0f8f1;
}

.impact-container {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 25px;
    margin-top: 40px;
}

.impact-card {
    background: white;
    padding: 35px 20px;
    border-radius: 20px;
    box-shadow: 0 8px 25px #183b2b10;
    transition: 0.3s;
}

.impact-card:hover {
    transform: translateY(-8px);
}

.impact-card span {
    font-size: 45px;
}

.impact-card h3 {
    margin: 18px 0;
    color: #159653;
}

.impact-card p {
    color: #607567;
}

@media (max-width: 800px) {
    .impact-container {
        grid-template-columns: 1fr;
    }
}

.quiz-box {
    max-width: 650px;
    margin: 35px auto 0;
    padding: 35px;
    background: white;
    border-radius: 24px;
    box-shadow: 0 10px 35px #183b2b15;
}

.quiz-box h3 {
    font-size: 22px;
    margin-bottom: 25px;
}

#answers {
    display: grid;
    gap: 12px;
}

.answer-btn {
    padding: 15px;
    border: 2px solid #dcebe0;
    border-radius: 12px;
    background: white;
    color: #244b36;
    cursor: pointer;
    font-size: 16px;
    text-align: left;
}

.answer-btn:hover {
    border-color: #159653;
    background: #eff9f1;
}

.answer-btn:disabled {
    cursor: default;
}

.answer-btn.correct {
    background: #d8f5df;
    border-color: #159653;
}

.answer-btn.wrong {
    background: #ffe5e5;
    border-color: #dc5555;
}

.quiz-box button:not(.answer-btn) {
    margin-top: 20px;
    padding: 14px 28px;
    background: #159653;
    color: white;
    border: none;
    border-radius: 30px;
    cursor: pointer;
}

.challenge {
    padding: 80px 8%;
    background: #f0f8f1;
    text-align: center;
}

.challenge-intro {
    color: #647568;
    margin: 15px 0 30px;
}

.challenge-progress {
    max-width: 600px;
    margin: 30px auto;
    padding: 25px;
    background: white;
    border-radius: 20px;
}

.progress-track {
    width: 100%;
    height: 12px;
    background: #e1eee3;
    border-radius: 20px;
    overflow: hidden;
    margin-top: 15px;
}

#progress-fill {
    width: 0%;
    height: 100%;
    background: #159653;
    transition: width 0.4s;
}

.challenge-list {
    max-width: 700px;
    margin: 30px auto;
    display: grid;
    gap: 15px;
    text-align: left;
}

.challenge-card {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 20px;
    background: white;
    border-radius: 16px;
    box-shadow: 0 5px 20px #183b2b10;
}

.challenge-card input {
    width: 20px;
    height: 20px;
    accent-color: #159653;
}

.challenge-card.completed {
    background: #e0f4e5;
}

#challenge-message {
    color: #159653;
    font-weight: bold;
    margin-top: 20px;
}