:root {
    --bg-primary: #f5f7fa; --bg-secondary: #ffffff; --text-primary: #1a1a2e;
    --text-secondary: #4a4a6a; --accent: #10b981; --accent-hover: #059669;
    --border: #e0e6ed; --shadow: 0 4px 6px rgba(0,0,0,0.1); --radius: 12px;
}
[data-theme="dark"] {
    --bg-primary: #0f0f1a; --bg-secondary: #1a1a2e; --text-primary: #ffffff;
    --text-secondary: #a0a0c0; --border: #2d2d4a;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; background: var(--bg-primary); color: var(--text-primary); line-height: 1.6; }
.container { max-width: 900px; margin: 0 auto; padding: 20px; }
header { text-align: center; padding: 40px 20px; background: var(--bg-secondary); border-radius: var(--radius); margin-bottom: 30px; box-shadow: var(--shadow); position: relative; }
header h1 { font-size: 2.5rem; margin-bottom: 10px; color: var(--accent); }
.tagline { color: var(--text-secondary); }
.dark-mode-btn { position: absolute; top: 20px; right: 20px; background: var(--bg-primary); border: 2px solid var(--border); border-radius: 50%; width: 45px; height: 45px; font-size: 1.3rem; cursor: pointer; }
.converter-card { background: var(--bg-secondary); border-radius: var(--radius); padding: 30px; margin-bottom: 25px; box-shadow: var(--shadow); }
.input-section, .output-section { margin-bottom: 20px; }
.input-section label, .output-section label { display: block; margin-bottom: 10px; font-weight: 600; color: var(--text-secondary); }
textarea { width: 100%; padding: 15px; border: 2px solid var(--border); border-radius: 8px; font-size: 1rem; background: var(--bg-primary); color: var(--text-primary); resize: vertical; font-family: inherit; }
textarea:focus { outline: none; border-color: var(--accent); }
.stats { margin-top: 10px; font-size: 0.9rem; color: var(--text-secondary); }
.buttons-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(130px, 1fr)); gap: 10px; margin: 20px 0; }
.buttons-grid button { padding: 12px 15px; background: var(--accent); color: white; border: none; border-radius: 8px; font-size: 0.95rem; font-weight: 600; cursor: pointer; transition: all 0.3s; }
.buttons-grid button:hover { background: var(--accent-hover); transform: translateY(-2px); }
.action-buttons { display: flex; gap: 10px; margin-top: 15px; flex-wrap: wrap; }
.action-btn { padding: 10px 20px; background: var(--bg-primary); color: var(--text-primary); border: 2px solid var(--border); border-radius: 8px; cursor: pointer; font-weight: 500; transition: all 0.3s; }
.action-btn:hover { border-color: var(--accent); color: var(--accent); }
.trust-badges { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 15px; margin: 40px 0; }
.badge { display: flex; align-items: center; gap: 10px; padding: 15px 20px; background: var(--bg-secondary); border-radius: var(--radius); box-shadow: var(--shadow); font-weight: 600; color: var(--text-secondary); }
.badge-icon { font-size: 1.5rem; }
.faq-section { background: var(--bg-secondary); border-radius: var(--radius); padding: 30px; margin: 30px 0; box-shadow: var(--shadow); }
.faq-section h2 { color: var(--accent); margin-bottom: 20px; }
.faq-item { border-bottom: 1px solid var(--border); padding: 15px 0; }
.faq-item:last-child { border-bottom: none; }
.faq-item summary { font-weight: 600; cursor: pointer; padding: 10px 0; list-style: none; }
.faq-item summary::after { content: '+'; float: right; font-size: 1.5rem; color: var(--accent); }
.faq-item[open] summary::after { content: '−'; }
.faq-item p { padding: 15px 0; color: var(--text-secondary); }
footer { text-align: center; padding: 30px; color: var(--text-secondary); }
@media (max-width: 768px) {
    header h1 { font-size: 1.8rem; }
    .dark-mode-btn { position: static; margin-top: 15px; }
    .buttons-grid { grid-template-columns: repeat(2, 1fr); }
}