/* CSS Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --secondary-color: #10b981;
    --background: #0f172a;
    --surface: #1e293b;
    --surface-hover: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --border-color: #334155;
    --success-color: #22c55e;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
    --radius: 12px;
    --radius-sm: 8px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
}

.app-container {
    max-width: 900px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header Styles */
header {
    text-align: center;
    margin-bottom: 30px;
    padding: 20px 0;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 10px;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* Main Content */
main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

/* Mode Selector */
.mode-selector {
    display: flex;
    gap: 10px;
    background: var(--surface);
    padding: 8px;
    border-radius: var(--radius);
}

.mode-btn {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 14px 20px;
    border: none;
    border-radius: var(--radius-sm);
    background: transparent;
    color: var(--text-secondary);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

.mode-btn:hover {
    background: var(--surface-hover);
    color: var(--text-primary);
}

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

.mode-btn .icon {
    font-size: 1.2rem;
}

/* Input Sections */
.input-section {
    display: none;
    background: var(--surface);
    padding: 24px;
    border-radius: var(--radius);
}

.input-section.active {
    display: block;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.input-group label {
    font-weight: 500;
    color: var(--text-secondary);
}

#text-input {
    padding: 16px;
    font-size: 1.1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    background: var(--background);
    color: var(--text-primary);
    transition: border-color 0.2s ease;
}

#text-input:focus {
    outline: none;
    border-color: var(--primary-color);
}

#text-input::placeholder {
    color: var(--text-secondary);
}

/* File Upload */
.file-upload-wrapper {
    position: relative;
    display: flex;
    align-items: center;
    gap: 15px;
    flex-wrap: wrap;
}

.file-upload-wrapper input[type="file"] {
    position: absolute;
    width: 100%;
    height: 100%;
    opacity: 0;
    cursor: pointer;
    z-index: 2;
}

.file-upload-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 24px;
    background: var(--primary-color);
    color: white;
    border-radius: var(--radius-sm);
    font-weight: 500;
    cursor: pointer;
    transition: background 0.2s ease;
}

.file-upload-wrapper:hover .file-upload-btn {
    background: var(--primary-hover);
}

.file-name {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Image Preview */
.image-preview-container {
    margin-top: 15px;
    text-align: center;
}

#image-preview {
    max-width: 100%;
    max-height: 200px;
    border-radius: var(--radius-sm);
    border: 2px solid var(--border-color);
}

/* Controls Section */
.controls-section {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    background: var(--surface);
    padding: 24px;
    border-radius: var(--radius);
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.control-group label {
    font-weight: 500;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

select {
    padding: 12px 16px;
    font-size: 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    background: var(--background);
    color: var(--text-primary);
    cursor: pointer;
    transition: border-color 0.2s ease;
}

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

/* Range Slider */
input[type="range"] {
    -webkit-appearance: none;
    width: 100%;
    height: 8px;
    border-radius: 4px;
    background: var(--border-color);
    outline: none;
    cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    transition: transform 0.2s ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.1);
}

input[type="range"]::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    border: none;
}

/* Checkbox */
.checkbox-label {
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
    padding-top: 8px;
}

.checkbox-label input[type="checkbox"] {
    width: 20px;
    height: 20px;
    accent-color: var(--primary-color);
    cursor: pointer;
}

/* Generate Button */
.generate-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    width: 100%;
    padding: 18px 32px;
    font-size: 1.1rem;
    font-weight: 600;
    border: none;
    border-radius: var(--radius);
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    box-shadow: var(--shadow);
}

.generate-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.4);
}

.generate-btn:active {
    transform: translateY(0);
}

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

/* Output Section */
.output-section {
    background: var(--surface);
    border-radius: var(--radius);
    overflow: hidden;
}

.output-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 24px;
    border-bottom: 1px solid var(--border-color);
}

.output-header h2 {
    font-size: 1.1rem;
    font-weight: 600;
}

.copy-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 10px 16px;
    font-size: 0.9rem;
    font-weight: 500;
    border: none;
    border-radius: var(--radius-sm);
    background: var(--surface-hover);
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.2s ease;
}

.copy-btn:hover:not(:disabled) {
    background: var(--primary-color);
}

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

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

.ascii-output {
    padding: 24px;
    font-family: 'Courier New', Consolas, monospace;
    font-size: 8px;
    line-height: 1.1;
    overflow-x: auto;
    white-space: pre;
    background: var(--background);
    color: var(--text-secondary);
    min-height: 150px;
    max-height: 500px;
    overflow-y: auto;
}

.ascii-output.has-content {
    color: var(--text-primary);
}

/* Footer */
footer {
    text-align: center;
    padding: 30px 20px;
    margin-top: auto;
    border-top: 1px solid var(--border-color);
}

footer p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s ease;
}

footer a:hover {
    color: var(--secondary-color);
    text-decoration: underline;
}

/* Responsive Design */
@media (max-width: 768px) {
    .app-container {
        padding: 15px;
    }

    header h1 {
        font-size: 1.8rem;
    }

    .subtitle {
        font-size: 0.95rem;
    }

    .mode-selector {
        flex-direction: column;
    }

    .mode-btn {
        padding: 12px 16px;
    }

    .controls-section {
        grid-template-columns: 1fr;
        padding: 20px;
    }

    .input-section {
        padding: 20px;
    }

    .generate-btn {
        padding: 16px 24px;
        font-size: 1rem;
    }

    .ascii-output {
        font-size: 6px;
        padding: 16px;
    }

    .output-header {
        padding: 12px 16px;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 1.5rem;
    }

    .mode-btn .icon {
        display: none;
    }

    .ascii-output {
        font-size: 5px;
    }
}

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

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

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

::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

/* Loading Animation */
@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

.loading {
    animation: pulse 1.5s ease-in-out infinite;
}