* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Montserrat', sans-serif;
}

body {
    position: relative;
    min-height: 100vh;
    overflow-x: hidden;
    background-color: #081c1b;
    background-image:
        radial-gradient(circle at 25% 12%, rgba(123, 255, 191, 0.24), transparent 18%),
        radial-gradient(circle at 80% 18%, rgba(94, 235, 194, 0.16), transparent 22%),
        radial-gradient(circle at 55% 82%, rgba(255, 255, 255, 0.08), transparent 24%);
    background-blend-mode: screen;
    color: #f0f6f4;
    line-height: 1.6;
    padding: 20px;
}

body::after {
    content: '';
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: -1;
    background-image:
        radial-gradient(circle at 30% 25%, rgba(255, 255, 255, 0.12), transparent 22%),
        radial-gradient(circle at 70% 75%, rgba(14, 107, 83, 0.08), transparent 28%),
        linear-gradient(180deg, rgba(255, 255, 255, 0.02), rgba(0, 0, 0, 0.08));
    opacity: 0.55;
    filter: blur(10px);
}

header {
    padding: 34px 24px;
    background: radial-gradient(circle at top left, rgba(173, 255, 207, 0.18), transparent 34%),
                linear-gradient(140deg, #0b443d 0%, #0f6b57 32%, #08403a 100%);
    color: white;
    border-radius: 22px;
    box-shadow: 0 20px 46px rgba(0, 0, 0, 0.28);
    margin-bottom: 24px;
    border: 1px solid rgba(255, 255, 255, 0.12);
}

.hero {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 20px;
    flex-wrap: wrap;
}

.eyebrow {
    text-transform: uppercase;
    letter-spacing: 1px;
    opacity: 0.8;
    margin-bottom: 10px;
}

header h1 {
    font-size: clamp(2rem, 3vw, 3rem);
    margin-bottom: 10px;
    font-weight: 800;
    letter-spacing: 0.03em;
    text-shadow: 0 2px 12px rgba(0, 0, 0, 0.22);
}

.lead {
    max-width: 720px;
    font-size: 1.05rem;
    color: #d8f1e4;
}

h2 {
    color: #7de3c8;
    margin-bottom: 16px;
    font-weight: 800;
    text-shadow: 0 1px 6px rgba(0, 0, 0, 0.15);
}

h3 {
    color: #a8f4d0;
    margin-bottom: 10px;
    font-weight: 700;
    text-shadow: 0 1px 4px rgba(0, 0, 0, 0.12);
}

.hero-actions {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 24px;
    border-radius: 999px;
    background: linear-gradient(135deg, #8df5cc 0%, #41ad84 100%);
    color: #042f28;
    text-decoration: none;
    font-weight: 800;
    letter-spacing: 0.02em;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    border: 2px solid rgba(255, 255, 255, 0.15);
}

.button:hover,
.button:focus {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(0, 77, 64, 0.18);
}

.button-secondary {
    background-color: rgba(255, 255, 255, 0.12);
    color: #d8f1e4;
    border-color: rgba(255, 255, 255, 0.18);
}

nav {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 12px;
    margin-bottom: 30px;
}

nav a {
    padding: 10px 16px;
    text-decoration: none;
    color: #d8f1e4;
    background-color: rgba(255, 255, 255, 0.08);
    border-radius: 999px;
    border: 1px solid rgba(255, 255, 255, 0.12);
    transition: background-color 0.2s ease, transform 0.2s ease;
}

nav a:hover {
    transform: translateY(-1px);
    background-color: rgba(255, 255, 255, 0.28);
}

.container {
    display: grid;
    grid-template-columns: minmax(260px, 320px) 1fr;
    gap: 24px;
}

.sidebar {
    display: grid;
    gap: 20px;
}

.card,
.highlight-card,
.mini-card {
    background-color: rgba(4, 29, 31, 0.82);
    color: #f2fbf6;
    padding: 22px;
    border-radius: 18px;
    border: 1px solid rgba(255, 255, 255, 0.12);
    box-shadow: 0 16px 38px rgba(0, 0, 0, 0.22);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
}

.highlight-card {
    border: 1px solid rgba(167, 255, 235, 0.45);
}

#glossary dl {
    color: #ffffff;
}

#glossary dt {
    margin-top: 14px;
    font-weight: 700;
    color: #ffffff;
}

#glossary dd {
    margin-left: 0;
    margin-bottom: 12px;
    color: #ffffff;
}

.content-grid {
    display: grid;
    gap: 24px;
}

.quiz-page .container {
    display: flex;
    justify-content: center;
    align-items: flex-start;
    min-height: calc(100vh - 220px);
}

.quiz-page .content-grid {
    width: min(100%, 900px);
    max-width: 1000px;
}

.quiz-page .card.quiz {
    padding: 34px;
}

.quiz-page .quiz-item {
    min-height: 420px;
}

.fact-list {
    list-style: disc inside;
    padding-left: 20px;
    margin-bottom: 18px;
}

.fact-list li {
    margin-bottom: 10px;
    color: #e6f7ee;
}

.dictionary-panel {
    margin-top: 24px;
    padding: 18px;
    background: rgba(9, 33, 36, 0.86);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 16px;
}


.dictionary-panel h3,
.dictionary-panel h4 {
    color: #bbf7d0;
    margin-bottom: 12px;
}

.dictionary-form {
    display: grid;
    gap: 14px;
    margin-bottom: 18px;
}

.dictionary-form label {
    display: grid;
    gap: 8px;
    font-weight: 600;
    color: #d8f1e4;
}

.dictionary-form input,
.dictionary-form textarea {
    width: 100%;
    padding: 12px 14px;
    border-radius: 14px;
    border: 1px solid rgba(255, 255, 255, 0.14);
    background-color: rgba(255, 255, 255, 0.08);
    color: #f7fff8;
    resize: vertical;
}

.dictionary-form textarea {
    min-height: 110px;
}

.dictionary-message {
    min-height: 22px;
    color: #b8f2d0;
    font-weight: 600;
}

.dictionary-message.error {
    color: #ffb3b3;
}

.dictionary-list-panel {
    margin-top: 10px;
}

.dictionary-list {
    list-style: none;
    padding-left: 0;
    display: grid;
    gap: 10px;
}

.dictionary-entry {
    background: rgba(255, 255, 255, 0.06);
    padding: 14px;
    border-radius: 14px;
    border: 1px solid rgba(255, 255, 255, 0.08);
    color: #ffffff;
}

p,
ul,
dl {
    margin-bottom: 16px;
}

ul {
    list-style: disc inside;
    padding-left: 16px;
}

.card-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px;
    margin-top: 18px;
}

.mini-card {
    padding: 18px;
}

.example {
    background-color: rgba(255, 255, 255, 0.08);
    padding: 16px;
    border-left: 5px solid #6af5d5;
    margin: 20px 0 0;
    border-radius: 10px;
    color: #e8fbf0;
}

.quiz {
    display: grid;
    gap: 18px;
}

.game-grid {
    display: grid;
    gap: 18px;
}

.game-item {
    background: rgba(10, 31, 33, 0.75);
    border: 1px solid rgba(255, 255, 255, 0.12);
    padding: 18px;
    border-radius: 16px;
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.game-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 14px 28px rgba(0, 0, 0, 0.22);
}

.game-feedback {
    margin-top: 14px;
    color: #d1f8e6;
    font-weight: 600;
}

.quiz-item {
    background: rgba(12, 44, 47, 0.85);
    color: #f4fbf5;
    padding: 18px;
    border-radius: 16px;
    border: 1px solid rgba(255, 255, 255, 0.12);
    transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
}

.card,
.mini-card {
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.card:hover,
.mini-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 22px 36px rgba(0, 0, 0, 0.32);
}

.button-group {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 10px;
}

button.button,
button.button-secondary {
    border: none;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease, opacity 0.2s ease;
}

button.button {
    background-color: #00796b;
    color: white;
}

button.button-secondary {
    background-color: rgba(255, 255, 255, 0.12);
    color: #e4fbf4;
    border: 1px solid rgba(255, 255, 255, 0.18);
}

button.button:hover,
button.button-secondary:hover {
    transform: translateY(-2px) scale(1.02);
    box-shadow: 0 10px 18px rgba(0, 77, 64, 0.18);
}

button.selected {
    outline: 3px solid #a7ffeb;
    box-shadow: 0 0 0 2px rgba(167, 255, 235, 0.35);
}

button.disabled {
    opacity: 0.55;
    cursor: default;
}

button.correct {
    border-color: #2e7d32;
}

button.correct-choice {
    background-color: #2e7d32;
    color: #e8f5e9;
}

button.wrong-choice {
    background-color: #c62828;
    color: white;
}

.quiz-item:hover {
    transform: translateY(-3px);
    box-shadow: 0 18px 28px rgba(0, 0, 0, 0.12);
    border-color: rgba(0, 121, 107, 0.35);
}

.feedback {
    margin-top: 14px;
    font-weight: 700;
    color: #dbf4dc;
}

.feedback-correct {
    color: #d8ffdc;
}
.quiz-result {
    margin-top: 24px;
    padding: 16px;
    border-radius: 14px;
    background-color: rgba(255, 255, 255, 0.08);
    border: 1px dashed rgba(167, 255, 235, 0.5);
    color: #e4fbf4;
    font-weight: 700;
}

dl {
    display: grid;
    gap: 12px;
}

dt {
    font-weight: 700;
    color: #004d40;
}

dd {
    margin-left: 0;
    color: #3e5f52;
}

footer {
    text-align: center;
    padding: 18px;
    margin-top: 30px;
    color: #ffffff;
    background-color: #004d40;
    border-radius: 18px;
}

@media (max-width: 980px) {
    .container {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 640px) {
    header,
    nav,
    .card,
    .highlight-card,
    .mini-card,
    footer {
        border-radius: 14px;
    }

    nav {
        justify-content: stretch;
    }

    nav a {
        flex: 1 1 auto;
        text-align: center;
    }

    .hero {
        flex-direction: column;
        align-items: flex-start;
    }

    .hero-actions {
        width: 100%;
    }
}