:root {
    /* Light Mode Variables */
    --bg-color: #f0f4f8;
    --card-bg: #FFFFFF;
    --primary-color: #007A4D; /* SA Green */
    --primary-color-hover: #005a3a;
    --secondary-color: #FFB612; /* SA Gold */
    --text-color: #262626;
    --light-text: #FFFFFF;
    --red-color: #DE3831;
    --blue-color: #007bff;
    --border-color: #e9ecef;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --hover-shadow: rgba(0, 0, 0, 0.15);
    --input-bg: #FFFFFF;
    --toast-bg: #262626;
    --modal-bg: rgba(0, 0, 0, 0.6);
    --modal-content-bg: #fefefe;

    /* Gradients */
    --body-gradient: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    --card-front-gradient: radial-gradient(circle, #f8fafd, #f0f4f8);
    --button-higher-gradient: linear-gradient(145deg, #e6f2ee, #ffffff);
    --button-lower-gradient: linear-gradient(145deg, #fdeeee, #ffffff);
}

@media (prefers-color-scheme: dark) {
    :root {
        /* Dark Mode Variables */
        --bg-color: #121212;
        --card-bg: #1E1E1E;
        --primary-color: #009e60; /* Brighter Green for Dark Mode */
        --primary-color-hover: #007A4D;
        --secondary-color: #FFC107; /* Brighter Gold */
        --text-color: #E0E0E0;
        --light-text: #FFFFFF;
        --red-color: #FF5252; /* Brighter Red */
        --blue-color: #448AFF;
        --border-color: #333333;
        --shadow-color: rgba(0, 0, 0, 0.5);
        --hover-shadow: rgba(0, 0, 0, 0.7);
        --input-bg: #2C2C2C;
        --toast-bg: #333333;
        --modal-bg: rgba(0, 0, 0, 0.8);
        --modal-content-bg: #1E1E1E;

        /* Gradients Dark */
        --body-gradient: linear-gradient(135deg, #1e1e1e 0%, #000000 100%);
        --card-front-gradient: radial-gradient(circle, #2a2a2a, #1e1e1e);
        --button-higher-gradient: linear-gradient(145deg, #0a3d2e, #1a1a1a);
        --button-lower-gradient: linear-gradient(145deg, #4a1c1c, #1a1a1a);
    }
}

body {
    font-family: 'Poppins', sans-serif;
    background: var(--bg-color); /* Fallback */
    background-image: var(--body-gradient);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    padding: 15px;
    -webkit-tap-highlight-color: transparent;
    transition: background 0.3s ease, color 0.3s ease;
}

#game-container {
    width: 100%;
    max-width: 420px; /* Slightly wider */
    background: var(--card-bg);
    border-radius: 24px;
    box-shadow: 0 20px 40px var(--shadow-color);
    padding: 35px;
    box-sizing: border-box;
    overflow: hidden;
    position: relative;
    text-align: center;
    perspective: 1000px;
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
    backdrop-filter: blur(10px); /* Glassmorphism effect */
    -webkit-backdrop-filter: blur(10px);
    display: flex;
    flex-direction: column;
    max-height: 95vh;
}

/* On larger screens, make the container pop more */
@media (min-width: 768px) {
    #game-container {
        max-width: 450px;
        box-shadow: 0 30px 60px var(--shadow-color);
        max-height: none;
        display: block;
    }
}

.screen {
    display: none;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    animation: fadeIn 0.4s cubic-bezier(0.16, 1, 0.3, 1); /* Smoother ease-out */
}

.screen.active {
    display: flex;
    flex-grow: 1;
    min-height: 0;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px) scale(0.98); }
    to { opacity: 1; transform: translateY(0) scale(1); }
}

/* --- Start Screen --- */
.logo h1 { font-size: 3.5rem; font-weight: 900; line-height: 0.95; margin: 0; color: var(--text-color); letter-spacing: -1px; }
.logo span { color: var(--primary-color); }
.logo p { font-size: 1.1rem; margin: 10px 0 35px; color: var(--text-color); opacity: 0.8; font-weight: 500; }
.high-score-display {
    background: var(--border-color);
    color: var(--text-color);
    padding: 10px 20px;
    border-radius: 50px;
    font-weight: 700;
    margin-bottom: 30px;
    font-size: 0.9rem;
    letter-spacing: 0.5px;
}
.footer-note { margin-top: 30px; font-size: 0.85rem; color: var(--text-color); opacity: 0.6; }

/* --- Game Screen --- */
.game-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    margin-bottom: 15px;
}

#score-streak { font-size: 1.2rem; font-weight: 700; color: var(--secondary-color); text-transform: uppercase; letter-spacing: 0.5px; }
#score-streak span { color: var(--text-color); }

.action-button.small {
    padding: 10px 16px;
    font-size: 0.85rem;
    width: auto;
    margin-bottom: 15px;
    border-radius: 8px;
}

#card {
    width: 100%;
    min-height: 450px; /* Default height for larger screens */
    margin-bottom: 25px;
    position: relative;
    flex-grow: 1;
}

#card-inner {
    position: relative;
    width: 100%;
    height: 100%;
    transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
    transform-style: preserve-3d;
    display: flex;
}

#card.is-flipped #card-inner {
    transform: rotateY(180deg);
}

#card-front, #card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    border-radius: 20px;
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 4px 15px var(--shadow-color);
}

/* Mobile responsive adjustments */
@media (max-width: 767px) {
    body {
        align-items: flex-start; /* Align to top on mobile */
        padding: 10px;
    }

    #game-container {
        padding: 20px;
        height: 95vh; /* Force full height on mobile */
        max-height: 98vh;
        border-radius: 16px;
    }

    #card {
        min-height: 200px; /* Ensure it doesn't collapse completely */
        margin-bottom: 15px;
        flex-shrink: 1; /* Allow it to shrink if needed */
    }

    #card-inner {
        min-height: 0;
    }

    /* Start Screen Mobile Adjustments */
    .logo h1 { font-size: 2.5rem; }
    .logo p { margin: 5px 0 20px; font-size: 1rem; }
    .high-score-display { margin-bottom: 15px; padding: 8px 16px; }
    .action-button { padding: 14px; margin-bottom: 10px; font-size: 1rem; }
    .footer-note { margin-top: 15px; display: none; } /* Hide footer note on small screens */

    /* Game Screen Mobile Adjustments */
    .game-header { margin-bottom: 10px; }
    .action-button.small { padding: 8px 12px; margin-bottom: 10px; font-size: 0.8rem; }

    #question-image-container {
        max-height: 100px; /* Smaller image on mobile */
        margin-bottom: 10px;
    }

    #question-text {
        font-size: 1rem;
        margin-bottom: 10px;
        line-height: 1.3;
    }

    .presented-value-container {
        padding: 8px 20px;
        margin-bottom: 10px;
    }

    #presented-value { font-size: 1.8rem; }

    #buttons-container { gap: 10px; }
    .choice-button { padding: 15px; font-size: 1.1rem; }

    /* End Screen Mobile Adjustments */
    #final-score { font-size: 4rem; }
    #final-score-container { margin: 10px 0; }
    #graded-title-container { padding: 8px 16px; margin-bottom: 15px; }
    #answer-reveal-container { padding: 12px; margin-bottom: 15px; }
    #reveal-correct-answer { font-size: 1.2rem; }
}

@media (max-height: 600px) {
    .logo h1 { font-size: 2rem; }
    #question-image-container { display: none !important; } /* Hide image on very short screens */
}

#card-front {
    background-color: var(--card-bg);
    background-image: var(--card-front-gradient);
    border: 2px solid var(--border-color);
    padding: 25px;
    transition: border-color 0.3s ease;
}

/* Feedback Styles */
#card-front.correct {
    border-color: var(--primary-color);
    box-shadow: 0 0 20px rgba(0, 122, 77, 0.3);
}

#card-front.incorrect {
    border-color: var(--red-color);
    box-shadow: 0 0 20px rgba(222, 56, 49, 0.3);
}

#card-back {
    background-color: var(--primary-color);
    background-image: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-color-hover) 100%);
    color: var(--light-text);
    transform: rotateY(180deg);
    display: flex;
    justify-content: center;
    align-items: center;
    border: none;
}

#card-back .logo h1 {
    font-size: 3rem;
    color: var(--light-text);
}

#card-back .logo span {
    color: var(--secondary-color);
}

/* Timer Styles */
#timer-container {
    width: 100%;
    height: 6px;
    background-color: var(--border-color);
    border-radius: 3px;
    position: absolute;
    top: 15px; /* Moved inside padding */
    left: 25px;
    right: 25px;
    width: calc(100% - 50px);
}
#timer-bar {
    width: 100%;
    height: 100%;
    background-color: var(--secondary-color);
    border-radius: 3px;
    transform-origin: left;
    transition: transform 10s linear;
}

/* Image Styles */
#question-image-container {
    width: 100%;
    max-height: 140px;
    margin-bottom: 20px;
    margin-top: 10px;
    display: none;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 10px var(--shadow-color);
}
#question-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

#question-text {
    font-size: 1.25rem;
    font-weight: 600;
    line-height: 1.4;
    margin-bottom: 20px;
    flex-grow: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-color);
}

.presented-value-container {
    background: var(--text-color);
    color: var(--bg-color); /* Inverted for contrast */
    padding: 12px 30px;
    border-radius: 16px;
    margin-bottom: 10px;
    box-shadow: 0 5px 15px var(--shadow-color);
}

#presented-value { font-size: 2.5rem; font-weight: 800; }

#buttons-container { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; width: 100%; }

.choice-button {
    padding: 22px;
    font-size: 1.4rem;
    font-weight: 700;
    border: none;
    border-radius: 16px;
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.25, 0.8, 0.25, 1);
    background: var(--card-bg);
    border: 2px solid transparent; /* Prepare for border transition if needed */
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    box-shadow: 0 4px 10px var(--shadow-color);
    position: relative;
    overflow: hidden;
}

.choice-button:hover {
    transform: translateY(-4px);
    box-shadow: 0 10px 25px var(--hover-shadow);
}

.choice-button:active {
    transform: translateY(0);
    box-shadow: 0 2px 5px var(--shadow-color);
}

#higher-button {
    color: var(--primary-color);
    background: var(--button-higher-gradient);
    border: 1px solid rgba(0, 122, 77, 0.1);
}

#higher-button::before {
    content: '';
    width: 24px;
    height: 24px;
    background-image: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="%23007A4D" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"><path d="M12 5v14m-7-7l7-7 7 7"/></svg>');
    background-repeat: no-repeat;
    background-position: center;
}
/* Dark mode icon adjustment via CSS filter or swapping SVG color not easily done inline,
   so we rely on the stroke color being set in the SVG data URI.
   Ideally, we'd use an inline SVG in HTML, but for now we keep the CSS approach.
*/

#lower-button {
    color: var(--red-color);
    background: var(--button-lower-gradient);
    border: 1px solid rgba(222, 56, 49, 0.1);
}

#lower-button::before {
    content: '';
    width: 24px;
    height: 24px;
    background-image: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="%23DE3831" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"><path d="M12 5v14m-7-7l7 7 7-7"/></svg>');
    background-repeat: no-repeat;
    background-position: center;
}

/* --- End Screen --- */
#final-score-title { font-size: 1.4rem; font-weight: 700; color: var(--text-color); margin: 0; opacity: 0.8; }
#final-score-container { color: var(--primary-color); margin: 15px 0; text-shadow: 0 2px 10px rgba(0,0,0,0.1); }
#final-score-container p { font-size: 1.1rem; margin: 0; font-weight: 600; color: var(--text-color); }
#final-score { font-size: 6rem; font-weight: 900; line-height: 1; letter-spacing: -3px; }

#graded-title-container {
    background: var(--secondary-color);
    color: #262626; /* Keep text dark on gold */
    padding: 12px 25px;
    border-radius: 50px;
    margin-bottom: 25px;
    display: inline-block;
    box-shadow: 0 4px 10px rgba(255, 182, 18, 0.3);
}
#graded-title-container p { margin: 0; font-weight: 700; font-size: 1.1rem; }

/* Answer Reveal */
#answer-reveal-container {
    background: var(--bg-color); /* Slightly different from card bg */
    width: 100%;
    padding: 20px;
    border-radius: 16px;
    margin-bottom: 25px;
    border: 1px solid var(--border-color);
}
#reveal-question-text {
    font-size: 0.95rem;
    color: var(--text-color);
    opacity: 0.7;
    margin: 0 0 8px 0;
    font-style: italic;
}
#reveal-correct-answer {
    font-size: 1.4rem;
    font-weight: 800;
    color: var(--primary-color);
}


/* --- Correct Answer Popup --- */
#answer-popup {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 122, 77, 0.95);
    color: var(--light-text);
    display: flex;
    justify-content: center;
    align-items: center;
    text-align: center;
    font-size: 1.5rem;
    font-weight: 700;
    padding: 20px;
    border-radius: 20px;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
    z-index: 10;
    pointer-events: none;
    backdrop-filter: blur(5px);
}

#answer-popup.show {
    opacity: 1;
    visibility: visible;
}

/* --- General Button Styles --- */
.action-button {
    width: 100%;
    padding: 18px;
    font-size: 1.1rem;
    font-weight: 700;
    border-radius: 14px;
    border: none;
    cursor: pointer;
    background-color: var(--primary-color);
    color: var(--light-text);
    transition: all 0.2s ease;
    margin-bottom: 12px;
    box-shadow: 0 4px 10px rgba(0, 122, 77, 0.2);
}
.action-button:hover {
    background-color: var(--primary-color-hover);
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(0, 122, 77, 0.3);
}

.action-button.secondary {
    background-color: transparent;
    color: var(--text-color);
    border: 2px solid var(--border-color);
    box-shadow: none;
}
.action-button.secondary:hover {
    background-color: var(--border-color);
    transform: translateY(-2px);
    color: var(--text-color);
}

#leaderboard-toggle-buttons button.secondary:hover {
    background-color: var(--border-color);
}

/* --- Feedback Animations --- */
.correct-answer { animation: correctAnswer 0.5s ease; }
@keyframes correctAnswer { 0%, 100% { transform: scale(1); } 50% { transform: scale(1.05); } }

.shake {
    animation: shake 0.5s cubic-bezier(.36,.07,.19,.97) both;
    transform: translate3d(0, 0, 0);
}

@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); }
}

/* --- Modal Styles --- */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: var(--modal-bg);
    animation: fadeInModal 0.3s ease;
    backdrop-filter: blur(5px);
}

.modal.is-active {
    display: block;
}

@keyframes fadeInModal {
    from { opacity: 0; }
    to { opacity: 1; }
}

.modal-content {
    background-color: var(--modal-content-bg);
    color: var(--text-color);
    margin: 30vh auto; /* Center vertically better */
    padding: 30px;
    border: 1px solid var(--border-color);
    width: 90%;
    max-width: 400px;
    border-radius: 20px;
    text-align: center;
    position: relative;
    box-shadow: 0 20px 50px rgba(0,0,0,0.3);
    animation: slideInModal 0.3s ease-out;
}

@keyframes slideInModal {
    from { transform: translateY(-30px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

.close-button {
    color: var(--text-color);
    opacity: 0.5;
    position: absolute;
    top: 15px;
    right: 20px;
    font-size: 28px;
    font-weight: bold;
    transition: opacity 0.2s;
}

.close-button:hover {
    opacity: 1;
    text-decoration: none;
    cursor: pointer;
}

/* Leaderboard & Highscore Input */
#leaderboard-list {
    list-style: none;
    padding: 0;
    width: 100%;
    text-align: left;
}
#leaderboard-list li {
    display: flex;
    justify-content: space-between;
    padding: 12px 16px;
    border-radius: 12px;
    margin-bottom: 8px;
    font-weight: 600;
    border: 1px solid var(--border-color);
    transition: background-color 0.2s;
}
#leaderboard-list li:nth-child(odd) {
    background-color: var(--bg-color);
}
#leaderboard-list li:hover {
    border-color: var(--primary-color);
}
#leaderboard-list li span:last-child {
    font-weight: 900;
    color: var(--primary-color);
}

#highscore-input-container {
    margin-top: 25px;
    width: 100%;
}
#player-initials {
    width: 100%;
    box-sizing: border-box;
    padding: 15px;
    margin-bottom: 12px;
    border-radius: 12px;
    border: 2px solid var(--border-color);
    text-align: center;
    font-size: 1.2rem;
    font-weight: 700;
    text-transform: uppercase;
    background-color: var(--input-bg);
    color: var(--text-color);
    transition: border-color 0.2s;
}
#player-initials:focus {
    outline: none;
    border-color: var(--primary-color);
}

/* Ad Container Styles */
#ad-container {
    margin: 20px 0;
    text-align: center;
    min-height: 100px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background: var(--bg-color);
    border-radius: 12px;
    padding: 10px;
}

#ad-container small {
    display: block;
    margin-bottom: 5px;
    color: var(--text-color);
    opacity: 0.5;
    font-size: 0.75rem;
}

#loading-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-color: var(--bg-color);
    color: var(--text-color);
    z-index: 1000;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.5rem;
    font-weight: 700;
}

/* --- Toast Notifications --- */
#toast-container {
    position: fixed;
    top: 30px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 2000;
    display: flex;
    flex-direction: column;
    gap: 12px;
    pointer-events: none;
    width: 90%;
    max-width: 350px;
}

.toast {
    background-color: var(--toast-bg);
    color: var(--light-text);
    padding: 14px 24px;
    border-radius: 16px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
    font-size: 0.95rem;
    font-weight: 500;
    opacity: 0;
    transform: translateY(-20px) scale(0.9);
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    pointer-events: auto;
    display: flex;
    align-items: center;
    gap: 12px;
    border: 1px solid rgba(255,255,255,0.1);
}

.toast.show {
    opacity: 1;
    transform: translateY(0) scale(1);
}

.toast.error {
    background-color: var(--red-color);
}

.toast.success {
    background-color: var(--primary-color);
}

.toast.info {
    background-color: var(--blue-color);
}

/* --- Mute Button --- */
.icon-button {
    position: absolute;
    top: 25px;
    right: 25px;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    z-index: 100;
    transition: transform 0.2s ease, background-color 0.2s;
    padding: 8px;
    border-radius: 50%;
    width: 44px;
    height: 44px;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: var(--card-bg);
    color: var(--text-color);
    box-shadow: 0 2px 8px var(--shadow-color);
}

.icon-button:hover {
    transform: scale(1.1);
    background-color: var(--bg-color);
}

.icon-button:active {
    transform: scale(0.95);
}

/* Position adjustment for mobile */
@media (max-width: 380px) {
    .icon-button {
        top: 15px;
        right: 15px;
        width: 38px;
        height: 38px;
    }
}

/* --- Lives Display --- */
#lives-display {
    font-size: 1.4rem;
    letter-spacing: 2px;
    margin-right: 15px;
    filter: drop-shadow(0 2px 4px var(--shadow-color));
}

.game-header {
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 10px;
    padding-right: 60px; /* Prevent overlap with mute button */
    align-items: center;
}

@media (max-width: 400px) {
    #lives-display {
        font-size: 1.2rem;
    }
    #score-streak {
        font-size: 0.9rem;
    }
}