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

:root {
    --primary-color: #06b6d4;
    --primary-dark: #0891b2;
    --success-color: #10b981;
    --bg-color: #f0f9ff;
    --card-bg: #ffffff;
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --border-color: #e5e7eb;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

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

.header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
    padding: 2rem 1rem;
    text-align: center;
    box-shadow: var(--shadow-lg);
}

.header h1 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.subtitle {
    opacity: 0.9;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

.api-key-section {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 60vh;
}

.api-key-card {
    background: var(--card-bg);
    padding: 3rem;
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
    max-width: 600px;
    width: 100%;
    text-align: center;
}

.api-key-card h2 {
    margin-bottom: 1rem;
    font-size: 1.75rem;
}

.info-text {
    color: var(--text-secondary);
    margin-bottom: 2rem;
    line-height: 1.8;
}

.api-key-form {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
}

.api-key-input {
    flex: 1;
    padding: 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
}

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

.help-text {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

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

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

.settings-bar {
    background: var(--card-bg);
    padding: 1rem 1.5rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.model-select {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.templates-section {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
}

.templates-section h2 {
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
}

.templates-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1rem;
}

.template-btn {
    padding: 1rem;
    background: var(--bg-color);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.template-btn:hover {
    border-color: var(--primary-color);
    background: rgba(6, 182, 212, 0.1);
    transform: translateY(-2px);
}

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

.editor-section {
    margin-bottom: 2rem;
}

.editor-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.input-panel,
.output-panel {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
}

.input-panel h3,
.output-panel h3 {
    margin-bottom: 1rem;
    font-size: 1.25rem;
}

.text-area {
    width: 100%;
    padding: 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
    resize: vertical;
    margin-bottom: 1rem;
}

.text-area:focus {
    outline: none;
    border-color: var(--primary-color);
}

.input-controls {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin-bottom: 1rem;
}

.tone-select,
.length-select {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.select-field {
    padding: 0.75rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    background: white;
}

.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

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

.btn-primary:hover:not(:disabled) {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.btn-large {
    width: 100%;
    padding: 1rem;
    font-size: 1.1rem;
}

.btn-secondary {
    padding: 0.5rem 1rem;
    background: var(--bg-color);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-secondary:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.output-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.btn-copy {
    padding: 0.5rem 1rem;
    background: var(--success-color);
    color: white;
    border: none;
    border-radius: 6px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-copy:hover {
    background: #059669;
    transform: scale(1.05);
}

.output-area {
    min-height: 300px;
    padding: 1.5rem;
    background: var(--bg-color);
    border-radius: 8px;
    white-space: pre-wrap;
    line-height: 1.8;
}

.placeholder-text {
    color: var(--text-secondary);
    font-style: italic;
    text-align: center;
    padding: 3rem 1rem;
}

.loading-indicator {
    text-align: center;
    padding: 3rem 1rem;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 1rem;
}

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

.history-section {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
}

.history-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.history-header h3 {
    font-size: 1.25rem;
}

.history-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.history-item {
    padding: 1rem;
    background: var(--bg-color);
    border-radius: 8px;
    border-left: 4px solid var(--primary-color);
    cursor: pointer;
    transition: all 0.3s;
}

.history-item:hover {
    transform: translateX(4px);
    box-shadow: var(--shadow);
}

.history-meta {
    display: flex;
    justify-content: space-between;
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.history-text {
    color: var(--text-primary);
    overflow: hidden;
    text-overflow: ellipsis;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
}

.empty-state {
    text-align: center;
    color: var(--text-secondary);
    padding: 2rem;
    font-style: italic;
}

@media (max-width: 768px) {
    .editor-grid {
        grid-template-columns: 1fr;
    }

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

    .settings-bar {
        flex-direction: column;
        gap: 1rem;
        align-items: stretch;
    }

    .input-controls {
        grid-template-columns: 1fr;
    }
}