:root {
    --bg-color: #e0e0e0;
    --card-bg-color: #303030;
    --header-card-bg-color: #f7f7f7;
    --text-color: #000000;
    --text-color-2: #ffffff;
    --accent-color: #008653;
    --accent-color-2: #00b46f;
    --medium-gray: #757575;
    --button-gray: #505050;
    --font-logo: 'knewave', cursive;
    --font-body: 'Roboto', sans-serif;
    --underline-color: #ffffff;
    /* ADDED VARIABLE FOR CORRECT ANSWER */
    --game-correct-color: #4CAF50; 
}

/* ... (previous CSS code from body to .audio-status remains the same) ... */
body { margin: 0; font-family: var(--font-body); background-color: var(--bg-color); color: var(--text-color); line-height: 1.6; max-width: 100%; overflow-x: hidden; }
.font-container { font-size: 16px; }
.page-container { max-width: clamp(320px, 1200px, 90vw); margin: 0 auto; box-sizing: border-box; }
header { height: auto; min-height: 70px; background-color: var(--card-bg-color); display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; padding: 15px 5vw; margin-bottom: 3em; }
.logo { font-family: var(--font-logo); font-size: clamp(1.8em, 4vw, 2.5em); color: var(--accent-color-2); margin-right: 20px; }
nav a { color: white; text-decoration: none; margin-left: clamp(15px, 3vw, 30px); font-size: clamp(1em, 2.5vw, 1.5em); transition: color 0.3s ease; }
nav a:hover { color: var(--accent-color); }
.chapter-title-card { background-color: var(--card-bg-color); padding: clamp(1em, 3vw, 2em) clamp(1.5em, 4vw, 2.6em); border-radius: 1.5em; margin-bottom: 3em; text-align: center; }
.chapter-title-card h2 { margin: 0; font-size: clamp(1.5em, 4vw, 2.5em); color: var(--accent-color-2); font-weight: 500; }
.collapsible-card { background-color: var(--header-card-bg-color); border-radius: 1.5em; margin-bottom: 25px; overflow: hidden; }
.collapsible-header { display: flex; justify-content: space-between; align-items: center; padding: clamp(1em, 3vw, 1.8em) clamp(1.5em, 4vw, 2.6em); cursor: pointer; background-color: var(--card-bg-color); }
.collapsible-header h3 { margin: 0; font-size: clamp(1.8em, 4.5vw, 2.8em); font-weight: 500; color: var(--text-color-2); }
.toggle-button { background-color: #4a4a4a; border: 1px solid #666; color: white; width: 32px; height: 32px; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-size: 24px; font-weight: bold; cursor: pointer; padding: 0; line-height: 1; transition: background-color 0.3s ease; flex-shrink: 0; }
.toggle-button:hover { background-color: #5a5a5a; }
.collapsible-content-wrapper { max-height: 10000px; opacity: 1; overflow: hidden; transition: max-height 0.7s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.5s ease-out 0.1s; }
.collapsible-content-wrapper.collapsed { max-height: 0; opacity: 0; transition: max-height 0.5s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.3s ease-in; }
.collapsible-content-inner { padding: 2em clamp(1.5em, 5vw, 4em); }
.story-image { display: block; width: 100%; max-width: 600px; margin-left: auto; margin-right: auto; height: auto; border-radius: 1em; margin-bottom: 25px; }
.content-block { border-radius: 1em; background-color: #ffffff; padding: clamp(1em, 3vw, 2em); margin-bottom: 25px; position: relative; }
.content-block:last-child { margin-bottom: 0; }
.content-block h4 { font-size: clamp(1.5em, 3.5vw, 2.2em); color: var(--text-color); margin-top: 0; margin-bottom: 0.75em; font-weight: 500; position: relative; padding-bottom: 0.5em; }
.content-block h4::after { content: ''; display: block; width: 100%; height: 1px; background-color: #eee; position: absolute; bottom: 0; left: 0; }
.story-text-section p { margin-bottom: 10px; font-size: clamp(1em, 2vw, 1.3em); }
.audio-player-section { margin-bottom: 2em !important; }
.audio-controls { display: flex; gap: 15px; margin-bottom: 20px; flex-wrap: wrap; align-items: center; }
.audio-btn { padding: 10px 18px; border: none; border-radius: 25px; font-size: clamp(0.9em, 2vw, 1em); font-weight: 500; cursor: pointer; transition: background-color 0.3s ease, transform 0.1s ease; display: inline-flex; align-items: center; justify-content: center; line-height: 1; }
.audio-btn:active { transform: scale(0.95); }
.play-pause-btn { background-color: var(--accent-color); color: white; padding: 12px; min-width: 50px; height: 50px; border-radius: 50%; display: inline-flex; align-items: center; justify-content: center; line-height: 1; }
.play-pause-btn:hover { background-color: #cc8e11; }
.play-pause-btn svg.icon { width: 24px; height: 24px; }
.play-pause-btn .icon-play { display: inline-block; }
.play-pause-btn .icon-pause { display: none; }
.play-pause-btn.playing .icon-play { display: none; }
.play-pause-btn.playing .icon-pause { display: inline-block; }
.stop-btn { background-color: var(--button-gray); color: var(--text-color-2); padding: 10px 20px; height: 50px; }
.stop-btn:hover { background-color: #505050; }
.audio-progress { display: flex; align-items: center; gap: 12px; margin-bottom: 10px; }
.time-display { font-size: clamp(0.85em, 1.8vw, 1em); color: #888; min-width: 40px; text-align: center; }
.progress-bar-container { flex-grow: 1; height: 10px; border-radius: 5px; position: relative; }
#progressBar { -webkit-appearance: none; appearance: none; width: 100%; height: 10px; border-radius: 5px; cursor: pointer; margin: 0; padding: 0; outline: none; background: var(--medium-gray); border: none; display: block; }
#progressBar::-webkit-slider-runnable-track { width: 100%; height: 10px; background: transparent; border: none; border-radius: 5px; }
#progressBar::-webkit-slider-thumb { -webkit-appearance: none; appearance: none; width: 20px; height: 20px; background: var(--accent-color); border-radius: 50%; border: 2px solid var(--card-bg-color); cursor: pointer; margin-top: -5px; box-shadow: 0 1px 3px rgba(0,0,0,0.2); }
#progressBar::-moz-range-track { width: 100%; height: 10px; background: var(--medium-gray); border: none; border-radius: 5px; }
#progressBar::-moz-range-progress { background-color: var(--accent-color); height: 10px; border-radius: 5px; }
#progressBar::-moz-range-thumb { width: 20px; height: 20px; background: var(--accent-color); border-radius: 50%; border: 2px solid var(--card-bg-color); cursor: pointer; box-shadow: 0 1px 3px rgba(0,0,0,0.2); }
.audio-status { font-size: clamp(0.8em, 1.6vw, 0.9em); color: #bebebe; margin: 0; }

#learn-rules-section .collapsible-content-inner { background-color: white; color: #333; padding: clamp(2em, 5vw, 4em); }
.grammar-rules-container { display: flex; flex-direction: column; gap: 2.5em; font-family: 'Georgia', serif; font-size: clamp(1rem, 2.2vw, 1.25rem); line-height: 1.6; max-width: 950px; margin: 0 auto; }
.grammar-rules-row { display: flex; flex-wrap: wrap; align-items: center; gap: clamp(1.5em, 4vw, 3em); }
.rules-main-text { flex: 1 1 380px; }
.rules-main-text ul { list-style-type: '•'; margin: 0; padding-left: 20px; color: #000; }
.rules-main-text li { padding-left: 12px; margin-bottom: 1em; }
.rules-main-text li::marker { color: #1a73e8; font-size: 1.5em; }
.rules-illustration-book { flex: 1 1 220px; display: flex; justify-content: center; align-items: center; }
.rules-illustration-book img { max-width: 100%; height: auto; }
.rules-illustration-chars { flex: 1 1 250px; display: flex; justify-content: center; }
.rules-illustration-chars img { max-width: 280px; width: 100%; height: auto; }
.rules-together-text { flex: 1 1 250px; font-size: clamp(1em, 2vw, 1.25em); font-weight: 500; line-height: 1.4; text-align: left; }
.rules-example-breakdown { flex: 1 1 300px; }
.rules-example-breakdown h4 { font-size: 1.2em; font-family: var(--font-body); color: black; margin: 0 0 1em 0; }
.rules-example-breakdown p { margin: 0.3em 0; font-size: 1.1em; }
.rules-example-box { flex: 1 1 300px; background-color: #fff9e6; border-radius: 10px; padding: clamp(1em, 3vw, 1.5em); font-family: var(--font-body); }
.rules-example-box h5 { margin: 0 0 1em 0; text-align: left; font-size: 1.2em; font-weight: 600; color: #555; }
.rules-example-box ul { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; gap: 1em; }
.rules-example-box li { display: flex; align-items: center; gap: 0.8em; font-size: 1.15em; color: #444; }
.rules-example-box .icon { font-size: 1.5em; }

/* ----------------------------- DRAG & DROP GAME STYLES (UPDATED) ----------------------------- */
.game-container { text-align: center; }
.game-title { font-size: clamp(2em, 5vw, 3em); color: var(--accent-color); margin-bottom: 0.4em; }
.game-instructions { font-size: clamp(1em, 2.2vw, 1.2em); color: black; margin-bottom: 2em; max-width: 600px; margin-left: auto; margin-right: auto; line-height: 1.5; }
.game-instructions strong { color: var(--accent-color); font-weight: 900; }

#sentence-builder-game {
    background-color: #f0f0f0;
    border-radius: 20px;
    padding: 30px clamp(15px, 4vw, 40px);
    box-shadow: inset 0 2px 8px rgba(0,0,0,0.1);
    display: flex;
    flex-direction: column;
    gap: 2.5em;
}

.drop-zones-container {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1em;
    flex-wrap: wrap;
}

.drop-zone {
    border: 3px dashed #a0a0a0;
    border-radius: 12px;
    min-height: 80px;
    width: 250px;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: background-color 0.3s, border-color 0.3s;
    position: relative;
    background-color: #e9e9e9;
}
.drop-zone.drag-over {
    background-color: #d4edda;
    border-color: var(--accent-color);
}
.drop-zone.incorrect {
    animation: shake 0.5s;
    border-color: #D32F2F;
}
.drop-zone-label {
    color: #888;
    font-size: 1.2em;
    font-weight: 500;
}
.plus-sign {
    font-size: 3em;
    font-weight: bold;
    color: var(--medium-gray);
}
.word-card {
    background-color: white;
    padding: 12px 20px;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.15);
    font-size: 1.2em;
    font-weight: 500;
    cursor: grab;
    transition: transform 0.2s, box-shadow 0.2s;
    user-select: none;
    touch-action: none;
}
.word-card:active {
    cursor: grabbing;
}
.word-card.dragging {
    opacity: 0.5;
    transform: scale(1.05);
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
}

.word-bank-container {
    border-top: 2px solid #ddd;
    padding-top: 1.5em;
    padding-left: 8em;
    padding-right: 8em;
    margin-top: 1em;
}
.word-bank-container h3 {
    margin: 0 0 1em 0;
    font-size: 1.5em;
    color: #444;
}
#word-bank {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 12px;
}

#sentence-result-container {
    min-height: 250px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 1em;
    opacity: 0;
    transform: scale(0.95);
    transition: opacity 0.5s ease-out, transform 0.5s ease-out;
}
#sentence-result-container.visible {
    opacity: 1;
    transform: scale(1);
}
#sentence-result-container .result-text {
    font-size: clamp(1.5em, 4vw, 2.2em);
    font-weight: bold;
    /* UPDATED: Green background and white text */
    background: linear-gradient(135deg, var(--game-correct-color), #388E3C);
    color: white; 
    padding: 10px 20px;
    border-radius: 10px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}
#sentence-result-container .result-image {
    max-width: 300px;
    max-height: 300px;
    width: 100%;
    border-radius: 12px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
}
.reset-button {
    background-color: var(--accent-color);
    color: white;
    border: none;
    padding: 12px 30px;
    font-size: 1.2em;
    font-weight: bold;
    border-radius: 25px;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.2s;
    margin: 1em auto 0;
    display: block;
}
.reset-button:hover {
    background-color: #006a42;
    transform: scale(1.05);
}

@keyframes shake { 10%, 90% { transform: translate3d(-1px, 0, 0); } 20%, 80% { transform: translate3d(2px, 0, 0); } 30%, 50%, 70% { transform: translate3d(-4px, 0, 0); } 40%, 60% { transform: translate3d(4px, 0, 0); } }

@media (max-width: 600px) {
    .drop-zone { width: 100%; max-width: 200px; }
    .drop-zones-container { flex-direction: column; }
}

@media (max-width: 1000px) {

    .word-bank-container {
    padding-left: 1em;
    padding-right: 1em;
}

}

/* ===================== NEXT CHAPTER BUTTON STYLES ===================== */
.next-chapter-container {
    text-align: center;
    margin: 4em 0 6em 0; /* Adds space above and below the button */
    padding: 0 20px; /* Prevents button from touching screen edges on mobile */
}

.next-chapter-btn {
    display: inline-block;
    background-color: var(--accent-color);
    color: white;
    padding: 16px 35px;
    font-size: clamp(1.1em, 3vw, 1.4em);
    font-weight: 700;
    text-decoration: none;
    border-radius: 50px; /* A pill shape to match other buttons */
    transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.next-chapter-btn:hover {
    background-color: var(--accent-color-2);
    transform: translateY(-3px) scale(1.03);
    box-shadow: 0 8px 15px rgba(0, 0, 0, 0.25);
}