:root {
    /* Color Palette - Default Light Mode */
    --bg-color: #f8f9fa;
    --surface-color: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-bg: #f1f5f9;
    --border-color: #e2e8f0;
    --success-color: #10b981;
    --error-color: #ef4444;

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);

    --font-heading: 'Inter', sans-serif;
    --font-body: 'Inter', sans-serif;
    --font-mono: 'JetBrains Mono', monospace;

    --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

.dark {
    --bg-color: #0f172a;
    --surface-color: #1e293b;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --primary-color: #3b82f6;
    --primary-hover: #60a5fa;
    --secondary-bg: #334155;
    --border-color: #334155;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 10px 15px -3px rgba(0, 0, 0, 0.4);
}

/* Base resets */
* { margin: 0; padding: 0; box-sizing: border-box; }
.hidden { display: none !important; }

body {
    font-family: var(--font-body);
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.app-container {
    flex: 1;
    width: 100%;
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 1rem 2rem 1rem;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

/* --- Navigation Top Bar --- */
.top-bar {
    position: sticky;
    top: 0;
    z-index: 100;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 1rem;
    margin: 0 -1rem 1.5rem -1rem;
    background: rgba(248, 249, 250, 0.82);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    transition: var(--transition);
}

.dark .top-bar {
    background: rgba(15, 23, 42, 0.82);
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
    color: var(--text-primary) !important;
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 600;
    transition: var(--transition);
    padding: 0.5rem 1rem;
    border-radius: var(--radius-md);
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
}

.back-link:hover {
    color: var(--primary-color) !important;
    border-color: var(--primary-color);
    transform: translateX(-3px);
    box-shadow: var(--shadow-md);
}

.back-link i {
    font-size: 0.8rem;
    transition: transform 0.2s ease;
}

.back-link:hover i {
    transform: translateX(-2px);
}

.theme-toggle-btn {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    width: 38px;
    height: 38px;
    border-radius: 12px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-primary);
    font-size: 1.1rem;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: var(--shadow-sm);
    position: relative;
    overflow: hidden;
}

.theme-toggle-btn:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    transform: rotate(5deg) scale(1.05);
    box-shadow: var(--shadow-md);
}

.theme-toggle-btn:active { transform: scale(0.95); }

/* Theme Icon logic - Robust control */
.mode-light, .mode-dark { display: none; }
body:not(.dark) .mode-dark { display: block; }
body.dark .mode-light { display: block; }

.dark .theme-toggle-btn { background: var(--secondary-bg); }

/* Header & Typography */
.main-header { text-align: center; margin-bottom: 0.5rem; }
.main-header h2 { font-size: 2rem; font-weight: 700; letter-spacing: -0.025em; color: var(--text-primary); }
.main-header .subtitle { color: var(--text-secondary); font-size: 1.1rem; }

/* Tool Components */
.tool-card {
    background-color: var(--surface-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    overflow: hidden;
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    transition: var(--transition);
}

.tabs { display: flex; border-bottom: 1px solid var(--border-color); background-color: var(--secondary-bg); }
.tab-btn {
    flex: 1; padding: 1.25rem; background: none; border: none; font-family: var(--font-body);
    font-size: 1rem; font-weight: 500; color: var(--text-secondary); cursor: pointer;
    transition: all 0.2s ease; border-bottom: 2px solid transparent;
    display: inline-flex; align-items: center; justify-content: center; gap: 0.5rem;
}
.tab-btn:hover { color: var(--primary-color); background-color: rgba(37, 99, 235, 0.05); }
.tab-btn.active { color: var(--primary-color); background-color: var(--surface-color); border-bottom-color: var(--primary-color); font-weight: 600; }

/* New badge on the CNPJ tab */
.tab-new-badge {
    display: inline-block;
    background: linear-gradient(135deg, #8b5cf6, #6366f1);
    color: white;
    font-size: 0.65rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    padding: 2px 7px;
    border-radius: 99px;
    vertical-align: middle;
    line-height: 1.4;
    box-shadow: 0 1px 4px rgba(99, 102, 241, 0.4);
}

/* Inline 'Novo' badge for checkbox label */
.inline-new-badge {
    display: inline-block;
    background: linear-gradient(135deg, #8b5cf6, #6366f1);
    color: white;
    font-size: 0.6rem;
    font-weight: 700;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    padding: 1px 6px;
    border-radius: 99px;
    margin-left: 0.35rem;
    vertical-align: middle;
    box-shadow: 0 1px 3px rgba(99, 102, 241, 0.35);
}

.tab-content { display: none; padding: 2.5rem; animation: fadeIn 0.3s ease; }
.tab-content.active { display: grid; grid-template-columns: 1fr 1px 1fr; gap: 2.5rem; align-items: start; }

@media (max-width: 850px) {
    .tab-content.active { display: flex; flex-direction: column; gap: 1.5rem; }
}

@keyframes fadeIn { from { opacity: 0; transform: translateY(5px); } to { opacity: 1; transform: translateY(0); } }

/* Forms */
.tool-group { display: flex; flex-direction: column; }
.tool-group h2 {
    font-size: 1.25rem; font-weight: 600; margin-bottom: 1.25rem; color: var(--text-primary);
    display: flex; align-items: center; gap: 0.5rem;
}
.tool-group h2::before { content: ''; display: block; width: 4px; height: 1.25rem; background-color: var(--primary-color); border-radius: 4px; }

.input-wrapper { position: relative; margin-bottom: 1rem; }
input[type="text"], select {
    width: 100%; padding: 0.875rem 1rem; font-size: 1.1rem; font-family: var(--font-mono);
    border: 1px solid var(--border-color); border-radius: var(--radius-sm);
    background-color: var(--bg-color); color: var(--text-primary); transition: var(--transition);
}
input[type="text"]:focus, select:focus { outline: none; border-color: var(--primary-color); box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1); }

.actions { display: flex; gap: 0.75rem; margin-bottom: 1.5rem; }
.btn {
    padding: 0.75rem 1.5rem; border-radius: var(--radius-sm); font-weight: 500; cursor: pointer;
    transition: all 0.2s ease; font-size: 0.95rem; border: none; display: inline-flex;
    align-items: center; justify-content: center; gap: 0.5rem;
}
.btn-primary { background-color: var(--primary-color); color: white; }
.btn-primary:hover { background-color: var(--primary-hover); transform: translateY(-1px); }
.btn-secondary { background-color: var(--surface-color); color: var(--text-primary); border: 1px solid var(--border-color); }
.btn-secondary:hover { border-color: var(--primary-color); color: var(--primary-color); }
.btn-ghost { background: transparent; color: var(--text-secondary); }
.btn-ghost:hover { color: var(--text-primary); background-color: var(--secondary-bg); }
.full-width { width: 100%; padding: 1rem; font-size: 1rem; font-weight: 600; }

.result-box { background-color: var(--secondary-bg); border-radius: var(--radius-sm); padding: 1.25rem; border: 1px solid var(--border-color); min-height: 140px; }
.result-box.hidden { display: none; }
.result-header { display: flex; align-items: center; flex-wrap: wrap; gap: 0.5rem; margin-bottom: 0.5rem; }
.validity-badge { display: inline-block; padding: 0.35rem 1rem; border-radius: 99px; font-size: 0.9rem; font-weight: 600; }
.validity-badge.valid { background-color: rgba(16, 185, 129, 0.15); color: var(--success-color); }
.validity-badge.invalid { background-color: rgba(239, 68, 68, 0.15); color: var(--error-color); }

/* Format detection badge (shown after CNPJ validation) */
.format-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    padding: 0.25rem 0.75rem;
    border-radius: 99px;
    font-size: 0.78rem;
    font-weight: 600;
    letter-spacing: 0.01em;
}
.format-badge.hidden { display: none; }
.format-badge--new {
    background: linear-gradient(135deg, rgba(139, 92, 246, 0.15), rgba(99, 102, 241, 0.15));
    color: #7c3aed;
    border: 1px solid rgba(139, 92, 246, 0.35);
}
.dark .format-badge--new {
    color: #a78bfa;
    border-color: rgba(167, 139, 250, 0.35);
}
.format-badge--legacy {
    background-color: rgba(100, 116, 139, 0.1);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}

.result-details { margin-top: 0.75rem; }
.result-details p { margin-bottom: 0.5rem; font-size: 0.95rem; color: var(--text-secondary); line-height: 1.5; }
.result-details span.mono { font-family: var(--font-mono); color: var(--text-primary); font-weight: 600; }
.note { font-size: 0.8rem; opacity: 0.8; margin-top: 0.75rem; display: block; }

.separator { background-color: var(--border-color); }
@media (min-width: 851px) { .separator { width: 1px; height: 100%; margin: 0; } }
@media (max-width: 850px) { .separator { height: 1px; width: 100%; margin: 0; } }

.options-grid { display: flex; flex-direction: column; gap: 1.25rem; margin-bottom: 1.25rem; }
.option label { display: block; margin-bottom: 0.5rem; font-size: 0.9rem; font-weight: 500; color: var(--text-secondary); }

.checkbox-option { display: flex; align-items: center; min-height: 24px; }
.custom-checkbox { display: inline-flex; align-items: center; cursor: pointer; font-size: 1rem; color: var(--text-primary); user-select: none; position: relative; padding-left: 0; }
.custom-checkbox input { position: absolute; opacity: 0; cursor: pointer; height: 0; width: 0; }
.checkmark { position: relative; height: 22px; width: 22px; background-color: var(--bg-color); border: 1px solid var(--border-color); border-radius: 4px; flex-shrink: 0; transition: all 0.2s; }
.checkbox-text { margin-left: 1.5rem; display: inline-block; }
.custom-checkbox:hover input~.checkmark { border-color: var(--primary-color); }
.custom-checkbox input:checked~.checkmark { background-color: var(--primary-color); border-color: var(--primary-color); }
.checkmark:after { content: ""; position: absolute; display: none; }
.custom-checkbox input:checked~.checkmark:after { display: block; }
.custom-checkbox .checkmark:after { left: 7px; top: 3px; width: 4px; height: 10px; border: solid white; border-width: 0 2px 2px 0; transform: rotate(45deg); }

.gen-output-wrapper { display: flex; gap: 0.5rem; margin-bottom: 1rem; }
.gen-output-wrapper input { margin-bottom: 0; cursor: default; background-color: var(--secondary-bg); }
.btn-icon {
    width: 52px; flex-shrink: 0; border: 1px solid var(--border-color); background-color: var(--surface-color);
    border-radius: var(--radius-sm); color: var(--text-secondary); cursor: pointer;
    transition: all 0.2s; font-size: 1.2rem; display: flex; align-items: center; justify-content: center;
}
.btn-icon:hover { color: var(--primary-color); border-color: var(--primary-color); background-color: rgba(37, 99, 235, 0.05); }
.copy-feedback { min-height: 1.5rem; margin-top: 0.5rem; font-size: 0.9rem; font-weight: 500; color: var(--success-color); text-align: center; transition: opacity 0.3s; }

/* Generated output highlight animation */
@keyframes genHighlight {
    0% { border-color: var(--primary-color); box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.25); }
    100% { border-color: var(--border-color); box-shadow: none; }
}
.gen-highlight { animation: genHighlight 0.9s ease forwards; }

/* Info note for alphanumeric CNPJ */
.alpha-note {
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.08), rgba(139, 92, 246, 0.08));
    border: 1px solid rgba(99, 102, 241, 0.25);
    border-radius: var(--radius-sm);
    padding: 0.75rem 1rem;
    font-size: 0.875rem;
    color: #4f46e5;
    line-height: 1.6;
    margin-bottom: 1rem;
    display: flex;
    gap: 0.6rem;
    align-items: flex-start;
}
.dark .alpha-note {
    color: #a5b4fc;
    border-color: rgba(99, 102, 241, 0.3);
    background: rgba(99, 102, 241, 0.1);
}
.alpha-note i { margin-top: 2px; flex-shrink: 0; }
.alpha-note.hidden { display: none; }

/* Accent checkmark for the 'new' option */
.checkmark--new {
    border-color: rgba(139, 92, 246, 0.5);
}
.custom-checkbox:hover input ~ .checkmark--new { border-color: #8b5cf6; }
.custom-checkbox input:checked ~ .checkmark--new {
    background: linear-gradient(135deg, #8b5cf6, #6366f1);
    border-color: #8b5cf6;
}

/* Mobile Optimizations */
@media (max-width: 640px) {
    .app-container { padding: 1rem; gap: 1rem; }
    .main-header h2 { font-size: 1.5rem; }
    .main-header .subtitle { font-size: 1rem; }
    .tab-content { padding: 1.25rem; }
    .top-bar { margin-bottom: 0.5rem; }
    .back-link { font-size: 0.8rem; padding: 0.4rem 0.6rem; }
    .btn { padding: 0.6rem 1rem; font-size: 0.875rem; }
    .tool-group h2 { font-size: 1.1rem; margin-bottom: 1rem; }
    input[type="text"], select { font-size: 1rem; padding: 0.75rem; }
    .separator { margin: 0.5rem 0; }
    .tab-btn { padding: 1rem 0.5rem; font-size: 0.9rem; }
    .footer { margin-top: 2rem; padding: 1.5rem 1rem; }
}

/* Footer */
.footer {
    padding: 2rem 1rem; font-family: var(--font-body); border-top: 1px solid var(--border-color);
    background-color: var(--surface-color); margin-top: 3rem;
}
.footer .container { max-width: 640px; margin: 0 auto; text-align: center; }
.support { margin-bottom: 2rem; }
.support-text { font-size: 1rem; color: var(--text-primary); margin-bottom: 1rem; }
.support-text .mono { font-family: var(--font-mono); background: var(--bg-color); padding: 2px 6px; border-radius: 4px; border: 1px solid var(--border-color); }
.support-actions { display: flex; justify-content: center; gap: 1rem; margin-bottom: 1rem; flex-wrap: wrap; }
.btn-support {
    display: inline-flex; align-items: center; gap: 0.5rem; padding: 0.6rem 1.2rem;
    background-color: transparent; border: 1px solid var(--border-color); color: var(--text-primary);
    border-radius: var(--radius-sm); font-size: 0.95rem; text-decoration: none; cursor: pointer; transition: all 0.2s ease;
}
.btn-support:hover { border-color: var(--primary-color); color: var(--primary-color); background-color: rgba(37, 99, 235, 0.05); }
.support-small { font-size: 0.875rem; color: var(--success-color); min-height: 1.5rem; font-weight: 500; }
.footer-note { font-size: 0.875rem; color: var(--text-secondary); margin-bottom: 0.5rem; }
.footer-note a, .copyright a { color: var(--text-primary); text-decoration: none; font-weight: 600; }
.footer-note a:hover, .copyright a:hover { text-decoration: underline; color: var(--primary-color); }
.copyright span { font-size: 0.875rem; color: var(--text-secondary); }