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

:root {
    --primary: #007acc;
    --primary-dark: #005a99;
    --secondary: #6c757d;
    --light: #f8f9fa;
    --dark: #212529;
    --gray: #e9ecef;
    --border: #dee2e6;
    --success: #28a745;
    --font-main: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
}

body {
    font-family: var(--font-main);
    line-height: 1.6;
    color: var(--dark);
    background-color: #ffffff;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Top Navigation */
.top-nav {
    background-color: #fff;
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
}

.top-nav .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
}

.top-nav nav a {
    margin-left: 1.5rem;
    text-decoration: none;
    color: var(--dark);
    font-weight: 500;
    transition: color 0.2s;
}

.top-nav nav a:hover {
    color: var(--primary);
}

/* Hero */
.hero {
    padding: 3rem 1rem;
    text-align: center;
    background-color: #fafafa;
}

.hero h1 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
    color: var(--dark);
}

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

.intro {
    font-size: 1rem;
    line-height: 1.7;
    max-width: 42rem;
    margin: 0 auto 1.5rem;
    color: var(--text);
}

.cta-button {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    background-color: var(--primary);
    color: white;
    text-decoration: none;
    border-radius: 6px;
    font-weight: 500;
    transition: background-color 0.2s;
}

.cta-button:hover {
    background-color: var(--primary-dark);
}

/* Section */
.section {
    padding: 2rem 1rem;
}

.section h2 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--dark);
}

/* Generator Form */
.generator-section {
    background-color: #ffffff;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    font-size: 0.9rem;
}

.form-group input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: 6px;
    font-size: 1rem;
    font-family: var(--font-main);
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(0, 122, 204, 0.1);
}

/* Chip Groups */
.chip-group {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.chip {
    padding: 0.5rem 1rem;
    border: 1px solid var(--border);
    background-color: #fff;
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.875rem;
    transition: all 0.2s;
    white-space: nowrap;
}

.chip:hover {
    background-color: var(--gray);
    border-color: var(--primary);
}

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

/* Actions */
.actions {
    display: flex;
    gap: 1rem;
    margin-top: 2rem;
    flex-wrap: wrap;
}

.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 6px;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

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

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

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

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

.btn.secondary:hover {
    background-color: #545b62;
}

.btn.tertiary {
    background-color: transparent;
    color: var(--secondary);
    border: 1px solid var(--border);
}

.btn.tertiary:hover {
    background-color: var(--gray);
}

/* Output Section */
.output-section {
    background-color: #f8f9fa;
}

.output-box {
    background-color: #fff;
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 1.5rem;
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.95rem;
    line-height: 1.8;
    min-height: 120px;
    white-space: pre-wrap;
    word-break: break-all;
}

/* Presets */
.presets-section {
    background-color: #ffffff;
}

.preset-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
}

.preset-card {
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1.5rem;
    background-color: #fafafa;
}

.preset-card h3 {
    margin-bottom: 0.5rem;
    color: var(--dark);
}

.preset-card p {
    margin-bottom: 1rem;
    color: var(--secondary);
    font-size: 0.95rem;
}

/* FAQ */
.faq-section {
    background-color: #f8f9fa;
}

.faq-list {
    display: grid;
    gap: 1rem;
}

.faq-item {
    background-color: #fff;
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1.5rem;
}

.faq-item h3 {
    margin-bottom: 0.5rem;
    font-size: 1rem;
}

.faq-item p {
    color: var(--secondary);
    font-size: 0.95rem;
}

/* Tips */
.tips-list {
    max-width: 720px;
    margin: 0 auto;
    padding-left: 1.25rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.tips-list li {
    background-color: #fff;
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1rem 1.25rem;
    font-size: 0.95rem;
    line-height: 1.6;
    list-style-position: inside;
}

.tips-list li::marker {
    font-weight: 700;
    color: var(--primary);
}

/* Footer */
footer {
    background-color: #222;
    color: #adb5bd;
    padding: 2rem 1rem;
    text-align: center;
}

footer p {
    margin: 0.5rem 0;
    font-size: 0.9rem;
}

/* Responsive */
@media (min-width: 768px) {
    .hero {
        padding: 4rem 1rem;
    }

    .hero h1 {
        font-size: 2.5rem;
    }

    .chip-group {
        justify-content: center;
    }

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

    .actions {
        justify-content: flex-start;
    }
}

@media (min-width: 1024px) {
    .preset-grid {
        grid-template-columns: repeat(3, 1fr);
    }

    .form-group {
        margin-bottom: 1.5rem;
    }
}
.mode-toggle {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.mode-btn {
    padding: 0.6rem 1.2rem;
    border: 2px solid var(--border, #e5e7eb);
    border-radius: 999px;
    background: #fff;
    cursor: pointer;
    font-size: 0.95rem;
}

.mode-btn.active {
    background: var(--primary);
    color: #fff;
    border-color: var(--primary);
}

.ref-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.ref-row {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.ref-num {
    flex: 0 0 4.5rem;
    font-weight: 600;
    font-size: 0.9rem;
}

.ref-input {
    flex: 1;
}

.settings-line {
    margin-top: 0.75rem;
    font-size: 0.9rem;
    color: var(--secondary);
}

.logo a {
    color: inherit;
    text-decoration: none;
}