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

:root {
    --primary-bg: #ffffff;
    --secondary-bg: #f5f5f5;
    --tertiary-bg: #f0f0f0;
    --primary-text: #1a1a1a;
    --secondary-text: #666666;
    --border-color: #e0e0e0;
    --button-bg: #007bff;
    --button-hover: #0056b3;
    --accent-color: #ff6b6b;
    --success-color: #28a745;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.15);
}

@media (prefers-color-scheme: dark) {
    :root {
        --primary-bg: #0f0f0f;
        --secondary-bg: #1a1a1a;
        --tertiary-bg: #2d2d2d;
        --primary-text: #ffffff;
        --secondary-text: #b0b0b0;
        --border-color: #3a3a3a;
        --button-bg: #0d6efd;
        --button-hover: #0b5ed7;
        --shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
        --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.4);
    }
}

html.light-theme {
    --primary-bg: #ffffff;
    --secondary-bg: #f5f5f5;
    --tertiary-bg: #f0f0f0;
    --primary-text: #1a1a1a;
    --secondary-text: #666666;
    --border-color: #e0e0e0;
}

html.dark-theme {
    --primary-bg: #0f0f0f;
    --secondary-bg: #1a1a1a;
    --tertiary-bg: #2d2d2d;
    --primary-text: #ffffff;
    --secondary-text: #b0b0b0;
    --border-color: #3a3a3a;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--primary-bg);
    color: var(--primary-text);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 700px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

header {
    margin-bottom: 40px;
    padding-top: 20px;
}

.header-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

header h1 {
    font-size: 2.5rem;
    background: linear-gradient(135deg, var(--button-bg), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.header-controls {
    display: flex;
    gap: 10px;
}

.theme-btn {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 2px solid var(--border-color);
    background-color: var(--secondary-bg);
    color: var(--primary-text);
    cursor: pointer;
    font-size: 1.2rem;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-btn:hover {
    transform: scale(1.1);
    border-color: var(--button-bg);
    box-shadow: 0 0 8px rgba(13, 110, 253, 0.3);
}

.theme-icon {
    display: inline-block;
    transition: transform 0.3s ease;
}

.theme-icon.rotating {
    animation: spin 0.6s ease-in-out;
}

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

.subtitle {
    color: var(--secondary-text);
    font-size: 1rem;
}

main {
    flex: 1;
}

/* Section Header */
.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}

.section-header label,
.section-header h2,
.section-header h3 {
    color: var(--primary-text);
    font-weight: 600;
}

.char-count {
    font-size: 0.85rem;
    color: var(--secondary-text);
}

/* Input Section */
.input-section {
    margin-bottom: 20px;
}

textarea {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-family: 'Courier New', monospace;
    font-size: 1rem;
    background-color: var(--secondary-bg);
    color: var(--primary-text);
    resize: vertical;
    transition: all 0.3s ease;
}

textarea:focus {
    outline: none;
    border-color: var(--button-bg);
    box-shadow: 0 0 0 3px rgba(13, 110, 253, 0.1);
}

textarea::placeholder {
    color: var(--secondary-text);
    opacity: 0.7;
}

/* Preview Toggle */
.preview-toggle {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 20px;
    padding: 10px;
    background-color: var(--tertiary-bg);
    border-radius: 8px;
}

.preview-toggle input[type="checkbox"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
    accent-color: var(--button-bg);
}

.preview-toggle label {
    cursor: pointer;
    user-select: none;
    margin: 0;
}

/* Effects Section */
.effects-section {
    margin-bottom: 30px;
}

.filter-group {
    display: flex;
    gap: 8px;
}

.effect-search {
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    background-color: var(--secondary-bg);
    color: var(--primary-text);
    font-size: 0.9rem;
    transition: all 0.3s ease;
}

.effect-search:focus {
    outline: none;
    border-color: var(--button-bg);
    box-shadow: 0 0 0 2px rgba(13, 110, 253, 0.1);
}

.button-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    gap: 10px;
}

.effect-btn {
    padding: 12px 14px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--secondary-bg);
    color: var(--primary-text);
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 6px;
    text-align: center;
}

.effect-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
    border-color: var(--button-bg);
}

.effect-btn.active {
    background-color: var(--button-bg);
    color: white;
    border-color: var(--button-bg);
    box-shadow: 0 4px 12px rgba(13, 110, 253, 0.3);
}

.effect-btn.hidden {
    display: none;
}

.btn-icon {
    font-size: 1.3rem;
}

/* Combination Section */
.combination-section {
    margin-bottom: 30px;
    padding: 15px;
    background-color: var(--tertiary-bg);
    border-radius: 8px;
    border-left: 4px solid var(--accent-color);
}

.combination-section h3 {
    margin-bottom: 10px;
    font-size: 0.95rem;
}

.selected-effects {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 10px;
    min-height: 30px;
}

.effect-tag {
    background-color: var(--button-bg);
    color: white;
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 0.85rem;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.effect-tag button {
    background: none;
    border: none;
    color: white;
    cursor: pointer;
    font-size: 0.9rem;
    padding: 0;
    margin-left: 4px;
    opacity: 0.7;
    transition: opacity 0.2s;
}

.effect-tag button:hover {
    opacity: 1;
}

/* Output Section */
.output-section {
    margin-bottom: 30px;
    padding: 20px;
    background-color: var(--tertiary-bg);
    border-radius: 12px;
    box-shadow: var(--shadow);
}

.output-actions {
    display: flex;
    gap: 8px;
}

.action-btn {
    width: 36px;
    height: 36px;
    border: none;
    border-radius: 6px;
    background-color: var(--secondary-bg);
    cursor: pointer;
    font-size: 1rem;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

.action-btn.active {
    background-color: var(--accent-color);
    color: white;
}

.output-container {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

#outputText {
    flex: 1;
    padding: 15px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--primary-bg);
    color: var(--primary-text);
    font-family: 'Courier New', monospace;
    font-size: 1rem;
    word-break: break-all;
    min-height: 100px;
    max-height: 250px;
    overflow-y: auto;
    user-select: all;
    line-height: 1.8;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0.7; }
    to { opacity: 1; }
}

.output-buttons {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.copy-btn {
    padding: 12px 16px;
    border: none;
    border-radius: 8px;
    background-color: var(--accent-color);
    color: white;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    white-space: nowrap;
    height: fit-content;
}

.copy-btn:hover {
    background-color: #ff5252;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(255, 107, 107, 0.3);
}

.copy-btn.copied {
    background-color: var(--success-color);
}

.copy-icon {
    font-size: 1rem;
}

/* History Section */
.history-section,
.favorites-section {
    margin-bottom: 30px;
    padding: 20px;
    background-color: var(--tertiary-bg);
    border-radius: 12px;
    box-shadow: var(--shadow);
}

.history-section h3,
.favorites-section h3 {
    margin-bottom: 15px;
    font-size: 1.1rem;
}

.history-list,
.favorites-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 12px;
}

.history-item,
.favorite-item {
    padding: 12px;
    background-color: var(--primary-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    word-break: break-all;
    font-size: 0.9rem;
}

.history-item:hover,
.favorite-item:hover {
    border-color: var(--button-bg);
    box-shadow: 0 4px 12px rgba(13, 110, 253, 0.2);
    transform: translateY(-2px);
}

.history-item .meta,
.favorite-item .meta {
    font-size: 0.75rem;
    color: var(--secondary-text);
    margin-top: 8px;
    padding-top: 8px;
    border-top: 1px solid var(--border-color);
}

.empty-state {
    text-align: center;
    color: var(--secondary-text);
    padding: 30px 20px;
    grid-column: 1 / -1;
}

/* Buttons */
.secondary-btn {
    padding: 8px 16px;
    border: 1px solid var(--border-color);
    background-color: var(--secondary-bg);
    color: var(--primary-text);
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.85rem;
    transition: all 0.3s ease;
}

.secondary-btn:hover {
    border-color: var(--button-bg);
    background-color: var(--button-bg);
    color: white;
}

/* Info Section */
.info-section {
    background-color: var(--secondary-bg);
    padding: 15px;
    border-radius: 8px;
    border-left: 4px solid var(--button-bg);
    color: var(--secondary-text);
    font-size: 0.9rem;
    margin-bottom: 30px;
}

/* Footer */
footer {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
    color: var(--secondary-text);
    font-size: 0.85rem;
}

footer a {
    color: var(--button-bg);
    text-decoration: none;
    transition: opacity 0.3s;
}

footer a:hover {
    opacity: 0.8;
}

/* Scrollbar Styling */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--secondary-bg);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--button-bg);
}

/* Responsive */
@media (max-width: 600px) {
    .container {
        padding: 15px;
    }

    header h1 {
        font-size: 1.8rem;
    }

    .button-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .history-list,
    .favorites-list {
        grid-template-columns: 1fr;
    }

    .output-container {
        flex-direction: column;
    }

    .copy-btn {
        width: 100%;
    }

    .section-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
    }

    .filter-group {
        width: 100%;
    }

    .effect-search {
        width: 100%;
    }
}