:root {
    --primary-color: #2563eb; /* Royal Blue */
    --secondary-color: #60a5fa; /* Lighter Blue */
    --bg-color: #f3f4f6; /* Cool Gray */
    --text-color: #1f2937; /* Dark Gray */
    --success-color: #10b981; /* Emerald */
    --error-color: #ef4444; /* Red */
    --input-bg: #ffffff;
    --surface-color: #ffffff;
}

html {
    font-size: 16px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    padding: 20px;
    display: flex;
    justify-content: center;
    min-height: 100vh;
}

.container {
    max-width: 1000px;
    width: 95%;
    background-color: var(--surface-color);
    padding: 40px;
    border-radius: 16px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.05);
    transition: margin 0.3s, width 0.3s, padding 0.3s;
}

header {
    text-align: center;
    margin-bottom: 30px;
    border-bottom: 2px solid #e5e7eb;
    padding-bottom: 20px;
}

h1 {
    margin: 0 0 10px 0;
    font-size: 2.5rem;
    color: var(--primary-color);
}

.subtitle {
    color: #6b7280;
    font-size: 1.1rem;
}

.controls {
    display: flex;
    justify-content: center;
    gap: 15px;
    align-items: center;
    flex-wrap: wrap;
    margin-bottom: 30px;
}

select {
    padding: 10px 35px 10px 15px;
    font-size: 1rem;
    border: 2px solid #e5e7eb;
    border-radius: 8px;
    background-color: var(--input-bg);
    color: var(--text-color);
    cursor: pointer;
    font-weight: 500;
    appearance: none;
    -webkit-appearance: none;
    background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%236b7280' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
    background-repeat: no-repeat;
    background-position: right 12px center;
    background-size: 16px;
    transition: border-color 0.2s;
}

select:hover, select:focus {
    border-color: var(--primary-color);
    outline: none;
}

button {
    padding: 10px 24px;
    font-size: 1rem;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.2s ease;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

button:disabled {
    background-color: #e5e7eb !important;
    color: #9ca3af !important;
    cursor: not-allowed;
    transform: none !important;
}

#new-game-btn {
    background-color: var(--primary-color);
    color: white;
    box-shadow: 0 4px 6px rgba(37, 99, 235, 0.2);
}

#new-game-btn:hover {
    background-color: #1d4ed8;
    transform: translateY(-1px);
    box-shadow: 0 6px 8px rgba(37, 99, 235, 0.3);
}

#sentence-info {
    text-align: center;
    margin-bottom: 30px;
}

#sentence-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 5px;
}

#sentence-author {
    font-size: 1rem;
    color: #6b7280;
    font-style: italic;
}

.sentence-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
    font-size: 1.5rem;
    margin-bottom: 40px;
    width: 100%;
}

.sentence-line {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center; /* Center align vertically */
    gap: 8px; /* Slightly reduced gap as pills have padding */
    line-height: 2; /* Increased line height for pills */
    width: 100%;
    max-width: 900px;
}

.word-box {
    height: 48px;
    padding: 0 20px;
    border-radius: 999px; /* Pill shape */
    background-color: white;
    border: 2px solid #e5e7eb;
    color: var(--text-color);
    font-weight: 500;
    font-size: 1.1rem; /* Match input font size */
    user-select: none;
    box-shadow: 0 2px 0 #e5e7eb; /* Subtle 3D effect */
    transition: all 0.2s;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    box-sizing: border-box;
}

.word-box:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 0 #e5e7eb;
    border-color: var(--secondary-color);
}

.punctuation {
    font-size: 1.5rem;
    font-weight: 400;
    color: var(--text-color);
    margin: 0 2px;
}

.word-input {
    height: 48px;
    min-width: 50px;
    padding: 0 20px;
    font-size: 1.1rem; /* input font size needs to be readable */
    text-align: center;
    border: 2px solid #d1d5db;
    border-radius: 999px; /* Pill shape */
    background-color: #f9fafb;
    font-family: inherit;
    outline: none;
    transition: all 0.2s;
    color: var(--primary-color);
    font-weight: 600;
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.05);
    box-sizing: border-box;
}

.word-input:focus,
.word-input.active-focus {
    border-color: var(--primary-color);
    background-color: #ffffff;
    box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.1);
    transform: translateY(-2px);
}

.word-input.correct {
    background-color: #d1fae5;
    border-color: var(--success-color);
    color: var(--success-color);
}

.word-input.incorrect {
    background-color: #fee2e2;
    border-color: var(--error-color);
    color: var(--error-color);
    animation: shake 0.4s ease-in-out;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

.game-actions {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-top: 20px;
    padding: 20px 0;
    border-top: 1px solid #f3f4f6;
}

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

.primary-btn:hover {
    background-color: #059669;
}

.secondary-btn {
    background-color: #f3f4f6;
    color: var(--text-color);
    border: 1px solid #e5e7eb;
}

.secondary-btn:hover {
    background-color: #e5e7eb;
    border-color: #d1d5db;
}

#message-area {
    text-align: center;
    margin-top: 15px;
    font-size: 1.2rem;
    font-weight: 600;
    min-height: 1.5em;
    color: var(--text-color);
    transition: color 0.3s;
}

/* Sort Mode Styles */
.sort-word {
    height: 48px;
    padding: 0 20px;
    background-color: white;
    border: 2px solid #e5e7eb;
    border-radius: 999px; /* Pill shape */
    cursor: grab;
    font-size: 1.1rem;
    transition: all 0.2s;
    box-shadow: 0 4px 0 #e5e7eb; /* Match pill effect */
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    box-sizing: border-box;
}

.sort-word:hover {
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: 0 6px 0 #e5e7eb; /* Lift effect */
}

.sort-word.dragging {
    opacity: 0.5;
    cursor: grabbing;
}

.sort-word.correct {
    background-color: #d1fae5;
    border-color: var(--success-color);
    color: #065f46;
}

.sort-word.incorrect {
    background-color: #fee2e2;
    border-color: var(--error-color);
    color: #991b1b;
}

.sort-word.selected {
    background-color: #eff6ff;
    border-color: var(--primary-color);
    color: var(--primary-color);
    transform: scale(1.05);
    z-index: 10;
}

/* Selection Pool */
.selection-pool {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    background-color: white;
    box-shadow: 0 -4px 20px rgba(0,0,0,0.1);
    padding: 20px;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
    z-index: 1000;
    border-top: 1px solid #e5e7eb;
    transition: transform 0.3s ease;
}

.selection-pool.hidden {
    transform: translateY(100%);
}

.pool-word {
    height: 48px;
    padding: 0 20px;
    background-color: white;
    border: 2px solid #e5e7eb;
    border-radius: 999px; /* Pill shape */
    cursor: pointer;
    font-size: 1.1rem;
    font-weight: 500;
    transition: all 0.2s;
    user-select: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    box-sizing: border-box;
    box-shadow: 0 2px 0 #e5e7eb;
}

.pool-word:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 0 #e5e7eb;
    border-color: var(--secondary-color);
}

.pool-word.muted {
    opacity: 0.5;
    background-color: #f3f4f6;
    color: #9ca3af;
    border-color: #e5e7eb;
    cursor: not-allowed;
    box-shadow: none;
    transform: none;
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 2000;
    backdrop-filter: blur(4px);
}

.modal.hidden {
    display: none;
}

.modal-content {
    background-color: white;
    width: 90%;
    max-width: 500px;
    border-radius: 16px;
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    overflow: hidden;
    animation: scaleIn 0.2s ease-out;
}

@keyframes scaleIn {
    from { transform: scale(0.95); opacity: 0; }
    to { transform: scale(1); opacity: 1; }
}

.modal-header {
    padding: 20px;
    background-color: #f9fafb;
    border-bottom: 1px solid #e5e7eb;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h2 {
    margin: 0;
    font-size: 1.25rem;
    color: var(--text-color);
}

.close-modal, .close-msg-modal {
    background: none;
    border: none;
    font-size: 1.5rem;
    color: #6b7280;
    cursor: pointer;
    padding: 0;
}

.modal-footer {
    padding: 20px;
    border-top: 1px solid #e5e7eb;
    display: flex;
    justify-content: flex-end;
    background-color: #f9fafb;
}

.modal-body {
    padding: 20px;
    max-height: 60vh;
    overflow-y: auto;
}

.topic-item {
    padding: 12px;
    margin-bottom: 8px;
    background-color: #f9fafb;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
}

.topic-item:hover {
    background-color: #eff6ff;
    color: var(--primary-color);
}

.topic-item-title {
    font-weight: 600;
    display: block;
}

.topic-item-detail {
    font-size: 0.85rem;
    color: #6b7280;
}

/* Responsive */
@media (max-width: 640px) {
    .container {
        padding: 20px;
    }
    
    h1 {
        font-size: 1.8rem;
    }
    
    .sentence-container {
        font-size: 1.2rem;
    }
    
    .word-input {
        min-width: 40px;
        font-size: 0.9rem;
    }
    
    .game-actions {
        flex-direction: column;
    }
    
    .game-actions button {
        width: 100%;
    }
}