:root {
    --primary-color: #667eea;
    --secondary-color: #764ba2;
    --success-color: #48bb78;
    --bg-color: #f7fafc;
    --card-bg: #ffffff;
    --text-color: #2d3748;
    --text-muted: #718096;
    --border-color: #e2e8f0;
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --transition: all 0.3s ease;
}

[data-theme="dark"] {
    --bg-color: #1a202c;
    --card-bg: #2d3748;
    --text-color: #f7fafc;
    --text-muted: #a0aec0;
    --border-color: #4a5568;
}

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

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

.container { max-width: 900px; margin: 0 auto; padding: 2rem 1rem; }

header { text-align: center; margin-bottom: 2rem; }
header h1 {
    font-size: 2.5rem;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.subtitle { color: var(--text-muted); font-size: 1.1rem; }

.mode-tabs {
    display: flex; gap: 0.5rem; justify-content: center; margin-bottom: 1.5rem; flex-wrap: wrap;
}

.mode-tab {
    padding: 0.75rem 1.25rem;
    background: var(--card-bg);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-lg);
    font-size: 0.95rem;
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-color);
}

.mode-tab:hover { border-color: var(--primary-color); }
.mode-tab.active {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border-color: transparent;
}

.converter-card {
    background: var(--card-bg);
    border-radius: var(--radius-xl);
    padding: 2rem;
    box-shadow: var(--shadow-lg);
    margin-bottom: 2rem;
}

.converter-section { display: none; }
.converter-section.active { display: block; }

.input-group { margin-bottom: 1rem; }
.input-group label { display: block; font-weight: 600; margin-bottom: 0.5rem; color: var(--text-muted); }

.input-group textarea {
    width: 100%;
    padding: 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-family: 'SF Mono', 'Consolas', monospace;
    background: var(--bg-color);
    color: var(--text-color);
    resize: vertical;
    transition: var(--transition);
}

.input-group textarea:focus { outline: none; border-color: var(--primary-color); }
.input-group textarea[readonly] { background: var(--card-bg); }

.input-options { margin-top: 0.5rem; font-size: 0.9rem; color: var(--text-muted); }
.input-options label { cursor: pointer; }

.swap-section { text-align: center; margin: 1rem 0; }

.swap-btn {
    padding: 0.75rem 2rem;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    border-radius: var(--radius-lg);
    font-size: 1.1rem;
    cursor: pointer;
    transition: var(--transition);
}

.swap-btn:hover { transform: scale(1.05); }

.options-row {
    display: flex; gap: 1.5rem; flex-wrap: wrap; margin-bottom: 1rem;
    font-size: 0.95rem; color: var(--text-muted);
}

.options-row label { display: flex; align-items: center; gap: 0.5rem; cursor: pointer; }

.conversion-buttons {
    display: flex; gap: 0.75rem; flex-wrap: wrap; margin-bottom: 1rem;
}

.convert-btn {
    flex: 1; min-width: 120px;
    padding: 0.75rem;
    background: var(--bg-color);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-color);
    font-weight: 500;
}

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

.action-buttons {
    display: flex; gap: 1rem; flex-wrap: wrap; margin-top: 1.5rem;
}

.action-btn {
    flex: 1; min-width: 120px;
    padding: 1rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-lg);
    background: var(--card-bg);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-color);
}

.action-btn:hover { border-color: var(--primary-color); }
.action-btn.primary {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border-color: transparent;
}

.ascii-section {
    background: var(--card-bg);
    border-radius: var(--radius-xl);
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
    margin-bottom: 2rem;
}

.ascii-section h2 { text-align: center; margin-bottom: 1rem; font-size: 1.25rem; }

.ascii-table-wrapper { overflow-x: auto; }

.ascii-table {
    width: 100%;
    border-collapse: collapse;
    font-family: 'SF Mono', monospace;
    font-size: 0.85rem;
}

.ascii-table th, .ascii-table td {
    padding: 0.5rem;
    text-align: center;
    border: 1px solid var(--border-color);
}

.ascii-table th { background: var(--bg-color); font-weight: 600; }
.ascii-table tr:hover td { background: rgba(102, 126, 234, 0.1); }

.trust-badges { display: flex; justify-content: center; gap: 1.5rem; flex-wrap: wrap; margin-bottom: 3rem; }
.badge { display: flex; align-items: center; gap: 0.5rem; padding: 0.5rem 1rem; background: var(--card-bg); border-radius: var(--radius-lg); box-shadow: 0 1px 2px rgba(0,0,0,0.05); }
.badge-icon { font-size: 1.25rem; }
.badge-text { font-size: 0.875rem; font-weight: 500; color: var(--text-muted); }

.features { margin-bottom: 3rem; }
.features h2 { text-align: center; font-size: 1.75rem; margin-bottom: 1.5rem; }
.features-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 1.5rem; }
.feature-card { background: var(--card-bg); border-radius: var(--radius-lg); padding: 1.5rem; box-shadow: 0 1px 2px rgba(0,0,0,0.05); text-align: center; transition: var(--transition); }
.feature-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); }
.feature-icon { font-size: 2.5rem; margin-bottom: 1rem; }
.feature-card h3 { font-size: 1.1rem; margin-bottom: 0.5rem; }
.feature-card p { font-size: 0.9rem; color: var(--text-muted); }

.faq-section { margin-bottom: 3rem; }
.faq-section h2 { text-align: center; font-size: 1.75rem; margin-bottom: 1.5rem; }
.faq-list { display: flex; flex-direction: column; gap: 0.75rem; }
.faq-item { background: var(--card-bg); border-radius: var(--radius-lg); overflow: hidden; }
.faq-question { width: 100%; padding: 1rem 1.25rem; text-align: left; background: none; border: none; font-size: 1rem; font-weight: 600; color: var(--text-color); cursor: pointer; display: flex; justify-content: space-between; }
.faq-question::after { content: '+'; font-size: 1.5rem; color: var(--primary-color); transition: var(--transition); }
.faq-item.active .faq-question::after { transform: rotate(45deg); }
.faq-answer { max-height: 0; overflow: hidden; transition: max-height 0.3s ease; }
.faq-item.active .faq-answer { max-height: 500px; }
.faq-answer p { padding: 0 1.25rem 1rem; color: var(--text-muted); }

footer { text-align: center; padding: 2rem 1rem; color: var(--text-muted); }

.theme-toggle { position: fixed; bottom: 2rem; right: 2rem; width: 50px; height: 50px; border-radius: 50%; background: var(--card-bg); border: 2px solid var(--border-color); box-shadow: var(--shadow-lg); cursor: pointer; display: flex; align-items: center; justify-content: center; z-index: 1000; }
.theme-toggle:hover { transform: scale(1.1); border-color: var(--primary-color); }
.theme-icon { font-size: 1.5rem; }