* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #1e88e5;
    --secondary-color: #43a047;
    --background-color: #f5f5f5;
    --card-color: #ffffff;
    --text-color: #333333;
    --border-color: #e0e0e0;
    --hover-color: #e3f2fd;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* Header */
.header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 40px 20px;
    border-radius: 12px;
    text-align: center;
    margin-bottom: 30px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.header h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
}

.header .subtitle {
    font-size: 1.1em;
    opacity: 0.9;
}

/* Controls */
.controls {
    background: var(--card-color);
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 20px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.dataset-selector {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 15px;
}

.dataset-selector label {
    font-weight: 600;
    white-space: nowrap;
}

.dataset-selector select {
    flex: 1;
    padding: 10px 14px;
    border: 2px solid var(--border-color);
    border-radius: 6px;
    font-size: 1em;
    background-color: white;
    cursor: pointer;
    transition: border-color 0.3s;
}

.dataset-selector select:focus {
    outline: none;
    border-color: var(--primary-color);
}

.search-box {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

.search-box input {
    flex: 1;
    padding: 12px 15px;
    border: 2px solid var(--border-color);
    border-radius: 6px;
    font-size: 1em;
    transition: border-color 0.3s;
}

.search-box input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.search-box button,
.btn {
    padding: 12px 20px;
    border: none;
    border-radius: 6px;
    font-size: 1em;
    cursor: pointer;
    transition: all 0.3s;
    font-weight: 500;
}

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

.btn:hover:not(:disabled) {
    background-color: #1565c0;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.15);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-secondary {
    background-color: var(--secondary-color);
}

.btn-secondary:hover:not(:disabled) {
    background-color: #388e3c;
}

.search-box button {
    background-color: var(--primary-color);
    color: white;
    padding: 12px 25px;
}

.pagination-controls {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 15px;
    margin: 20px 0;
}

.page-info {
    min-width: 150px;
    text-align: center;
    font-weight: 500;
    color: var(--text-color);
}

.stats {
    text-align: center;
    padding: 10px;
    background-color: var(--hover-color);
    border-radius: 6px;
    color: var(--primary-color);
    font-weight: 500;
}

/* Spinner */
.spinner {
    display: block;
    border: 4px solid var(--border-color);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin: 20px auto;
}

.spinner.hidden {
    display: none;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Error Message */
.error-message {
    background-color: #ffebee;
    color: #c62828;
    padding: 15px;
    border-radius: 6px;
    margin-bottom: 20px;
    border-left: 4px solid #c62828;
}

.error-message.hidden {
    display: none;
}

/* Dictionary Table */
.dictionary-container {
    background: var(--card-color);
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
    margin-bottom: 20px;
}

.dictionary-table {
    width: 100%;
    border-collapse: collapse;
}

.dictionary-table thead {
    background-color: var(--primary-color);
    color: white;
    position: sticky;
    top: 0;
}

.dictionary-table th {
    padding: 15px;
    text-align: left;
    font-weight: 600;
}

.dictionary-table td {
    padding: 12px 15px;
    border-bottom: 1px solid var(--border-color);
}

.dictionary-table tbody tr {
    transition: background-color 0.2s;
}

.dictionary-table tbody tr:hover {
    background-color: var(--hover-color);
}

.col-index {
    width: 60px;
    text-align: center;
}

.col-word {
    width: 22%;
    font-weight: 500;
    color: var(--primary-color);
}

.col-definition {
    width: 30%;
}

.col-extra {
    width: 42%;
    font-size: 0.95em;
}

.empty-state {
    text-align: center;
    padding: 40px;
    color: #999;
}

.empty-state p {
    font-size: 1.1em;
}

/* Pagination Bottom */
.pagination-bottom {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin: 20px 0;
}

/* Footer */
.footer {
    text-align: center;
    padding: 20px;
    color: #666;
    border-top: 1px solid var(--border-color);
    margin-top: 40px;
}

.footer a {
    color: var(--primary-color);
    text-decoration: none;
}

.footer a:hover {
    text-decoration: underline;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 10px;
    }

    .header h1 {
        font-size: 1.8em;
    }

    .header .subtitle {
        font-size: 0.9em;
    }

    .search-box {
        flex-direction: column;
    }

    .pagination-controls {
        flex-direction: column;
        gap: 10px;
    }

    .col-word {
        width: 25%;
    }

    .col-definition {
        width: 50%;
    }

    .col-extra {
        display: none;
    }

    .controls {
        padding: 15px;
    }

    .dictionary-table th,
    .dictionary-table td {
        padding: 10px;
        font-size: 0.9em;
    }
}

@media (max-width: 500px) {
    .header h1 {
        font-size: 1.5em;
    }

    .col-index {
        width: 40px;
    }

    .col-word {
        width: 30%;
    }

    .col-definition {
        width: 70%;
    }

    .pagination-bottom {
        gap: 10px;
    }

    .btn {
        padding: 10px 15px;
        font-size: 0.9em;
    }
}