/* Academic Calculators - Common Styles */
:root {
    --primary: #4f46e5;
    --primary-dark: #4338ca;
    --primary-light: #e0e7ff;
    --success: #10b981;
    --error: #ef4444;
    --warning: #f59e0b;
    --bg-body: #f8fafc;
    --bg-card: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border: #e2e8f0;
    --shadow: 0 4px 6px -1px rgba(0,0,0,0.1);
}
[data-theme="dark"] {
    --primary: #818cf8;
    --primary-dark: #6366f1;
    --primary-light: #312e81;
    --bg-body: #0f172a;
    --bg-card: #1e293b;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --border: #334155;
}
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: 80px; }
body { font-family: system-ui, -apple-system, sans-serif; background: var(--bg-body); color: var(--text-primary); line-height: 1.6; min-width: 320px; overflow-x: hidden; }

/* Skip Link */
.skip-link { position: absolute; top: -100%; left: 50%; transform: translateX(-50%); background: var(--primary); color: white; padding: 8px 16px; border-radius: 4px; z-index: 10000; text-decoration: none; }
.skip-link:focus { top: 10px; }

/* ==================== HEADER ==================== */
/* ==================== HEADER ==================== */
.site-header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: var(--bg-card);
    border-bottom: 1px solid var(--border);
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 16px;
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

/* Logo */
.site-logo {
    display: flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 700;
    font-size: 16px;
    flex-shrink: 0;
}

.logo-icon {
    font-size: 24px;
}

.logo-text {
    display: none;
}

@media (min-width: 480px) {
    .logo-text {
        display: inline;
    }
}

/* ==================== DESKTOP NAVIGATION ==================== */
.main-nav {
    display: none;
    align-items: center;
    gap: 4px;
}

@media (min-width: 900px) {
    .main-nav {
        display: flex;
    }
}

.nav-link {
    padding: 8px 14px;
    border-radius: 6px;
    text-decoration: none;
    color: var(--text-secondary);
    font-size: 14px;
    font-weight: 500;
    transition: all 0.2s;
    white-space: nowrap;
    border: none;
    background: none;
    cursor: pointer;
    font-family: inherit;
}

.nav-link:hover,
.nav-link.active {
    background: var(--primary-light);
    color: var(--primary);
}

/* ==================== DROPDOWN MENU ==================== */
.nav-dropdown {
    position: relative;
}

.dropdown-toggle {
    display: flex;
    align-items: center;
    gap: 4px;
}

.dropdown-arrow {
    font-size: 10px;
    transition: transform 0.2s;
}

.nav-dropdown:hover .dropdown-arrow,
.dropdown-toggle[aria-expanded="true"] .dropdown-arrow {
    transform: rotate(180deg);
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%) translateY(8px);
    min-width: 280px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 12px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.15);
    padding: 8px;
    opacity: 0;
    visibility: hidden;
    transition: all 0.2s ease;
    z-index: 1000;
}

/* Show dropdown on hover or when aria-expanded is true */
.nav-dropdown:hover .dropdown-menu,
.dropdown-toggle[aria-expanded="true"] + .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(0);
}

/* Arrow pointer */
.dropdown-menu::before {
    content: '';
    position: absolute;
    top: -6px;
    left: 50%;
    transform: translateX(-50%) rotate(45deg);
    width: 12px;
    height: 12px;
    background: var(--bg-card);
    border-left: 1px solid var(--border);
    border-top: 1px solid var(--border);
}

.dropdown-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 14px;
    border-radius: 8px;
    text-decoration: none;
    color: var(--text-primary);
    transition: all 0.15s;
}

.dropdown-item:hover {
    background: var(--primary-light);
}

.dropdown-icon {
    font-size: 20px;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--primary-light);
    border-radius: 8px;
    flex-shrink: 0;
}

.dropdown-item:hover .dropdown-icon {
    background: var(--primary);
}

.dropdown-item-content {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.dropdown-item-title {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-primary);
}

.dropdown-item-desc {
    font-size: 12px;
    color: var(--text-secondary);
}

.dropdown-divider {
    height: 1px;
    background: var(--border);
    margin: 8px 0;
}

/* ==================== HEADER ACTIONS ==================== */
.header-actions {
    display: flex;
    align-items: center;
    gap: 8px;
}

.theme-toggle,
.mobile-menu-toggle {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--bg-card);
    cursor: pointer;
    font-size: 18px;
    transition: all 0.2s;
}

.theme-toggle:hover,
.mobile-menu-toggle:hover {
    border-color: var(--primary);
    background: var(--primary-light);
}

.theme-toggle .icon-moon {
    display: none;
}

[data-theme="dark"] .theme-toggle .icon-sun {
    display: none;
}

[data-theme="dark"] .theme-toggle .icon-moon {
    display: inline;
}

@media (min-width: 900px) {
    .mobile-menu-toggle {
        display: none;
    }
}

/* Hamburger Icon */
.hamburger {
    width: 18px;
    height: 14px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.hamburger span {
    width: 100%;
    height: 2px;
    background: var(--text-primary);
    border-radius: 1px;
    transition: all 0.3s;
}

.mobile-menu-toggle.open .hamburger span:nth-child(1) {
    transform: rotate(45deg) translate(4px, 4px);
}

.mobile-menu-toggle.open .hamburger span:nth-child(2) {
    opacity: 0;
}

.mobile-menu-toggle.open .hamburger span:nth-child(3) {
    transform: rotate(-45deg) translate(4px, -4px);
}

/* ==================== MOBILE NAVIGATION ==================== */
.mobile-nav {
    display: none;
    background: var(--bg-card);
    border-bottom: 1px solid var(--border);
    padding: 12px 16px;
    animation: slideDown 0.3s ease;
    max-height: calc(100vh - 64px);
    overflow-y: auto;
}

.mobile-nav.open {
    display: block;
}

@media (min-width: 900px) {
    .mobile-nav {
        display: none !important;
    }
}

@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.mobile-nav-section {
    margin-bottom: 16px;
}

.mobile-nav-section:last-child {
    margin-bottom: 0;
}

.mobile-nav-title {
    font-size: 11px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
    padding: 8px 12px;
}

.mobile-nav-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.mobile-nav-link {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 12px 16px;
    border-radius: 8px;
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    font-size: 15px;
    transition: all 0.2s;
}

.mobile-nav-link:hover,
.mobile-nav-link.active {
    background: var(--primary-light);
    color: var(--primary);
}

.mobile-nav-link .nav-icon {
    font-size: 18px;
    width: 24px;
    text-align: center;
}

.mobile-nav-divider {
    height: 1px;
    background: var(--border);
    margin: 8px 0;
}
@media (min-width: 480px) { .logo-text { display: inline; } }

/* Main Navigation - Desktop */
.main-nav { display: none; align-items: center; gap: 4px; }
@media (min-width: 900px) { .main-nav { display: flex; } }
.nav-link { padding: 8px 14px; border-radius: 6px; text-decoration: none; color: var(--text-secondary); font-size: 14px; font-weight: 500; transition: all 0.2s; white-space: nowrap; }
.nav-link:hover, .nav-link.active { background: var(--primary-light); color: var(--primary); }

/* Header Actions */
.header-actions { display: flex; align-items: center; gap: 8px; }
.theme-toggle, .mobile-menu-toggle { width: 40px; height: 40px; display: flex; align-items: center; justify-content: center; border: 1px solid var(--border); border-radius: 8px; background: var(--bg-card); cursor: pointer; font-size: 18px; transition: all 0.2s; }
.theme-toggle:hover, .mobile-menu-toggle:hover { border-color: var(--primary); background: var(--primary-light); }
.theme-toggle .icon-moon { display: none; }
[data-theme="dark"] .theme-toggle .icon-sun { display: none; }
[data-theme="dark"] .theme-toggle .icon-moon { display: inline; }
@media (min-width: 900px) { .mobile-menu-toggle { display: none; } }
.hamburger { width: 18px; height: 14px; display: flex; flex-direction: column; justify-content: space-between; }
.hamburger span { width: 100%; height: 2px; background: var(--text-primary); border-radius: 1px; transition: all 0.3s; }
.mobile-menu-toggle.open .hamburger span:nth-child(1) { transform: rotate(45deg) translate(4px, 4px); }
.mobile-menu-toggle.open .hamburger span:nth-child(2) { opacity: 0; }
.mobile-menu-toggle.open .hamburger span:nth-child(3) { transform: rotate(-45deg) translate(4px, -4px); }

/* Mobile Navigation with Submenu */
.mobile-nav { display: none; background: var(--bg-card); border-bottom: 1px solid var(--border); padding: 12px 16px; animation: slideDown 0.3s ease; }
.mobile-nav.open { display: block; }
@media (min-width: 900px) { .mobile-nav { display: none !important; } }
@keyframes slideDown { from { opacity: 0; transform: translateY(-10px); } to { opacity: 1; transform: translateY(0); } }

.mobile-nav-section { margin-bottom: 16px; }
.mobile-nav-section:last-child { margin-bottom: 0; }
.mobile-nav-title { font-size: 11px; font-weight: 700; text-transform: uppercase; letter-spacing: 0.05em; color: var(--text-secondary); padding: 8px 12px; }
.mobile-nav-list { list-style: none; display: flex; flex-direction: column; gap: 2px; }
.mobile-nav-link { display: flex; align-items: center; gap: 10px; padding: 12px 16px; border-radius: 8px; text-decoration: none; color: var(--text-primary); font-weight: 500; font-size: 15px; transition: all 0.2s; }
.mobile-nav-link:hover, .mobile-nav-link.active { background: var(--primary-light); color: var(--primary); }
.mobile-nav-link .nav-icon { font-size: 18px; width: 24px; text-align: center; }
.mobile-nav-divider { height: 1px; background: var(--border); margin: 8px 0; }

/* ==================== PAGE LAYOUT ==================== */
.page-wrapper { max-width: 1200px; margin: 0 auto; padding: 20px 16px; display: grid; gap: 24px; }
@media (min-width: 1024px) { 
    .page-wrapper.with-sidebar { grid-template-columns: 220px 1fr; gap: 32px; } 
}

/* Sidebar */
.page-sidebar { display: none; }
@media (min-width: 1024px) { .page-sidebar { display: block; position: sticky; top: 88px; height: fit-content; } }
.toc-card { background: var(--bg-card); border-radius: 12px; padding: 20px; box-shadow: var(--shadow); }
.toc-title { font-size: 11px; font-weight: 700; color: var(--text-secondary); text-transform: uppercase; letter-spacing: 0.05em; margin-bottom: 12px; }
.toc-list { list-style: none; }
.toc-link { display: block; padding: 8px 12px; border-radius: 6px; text-decoration: none; color: var(--text-secondary); font-size: 14px; border-left: 2px solid transparent; margin-bottom: 2px; transition: all 0.2s; }
.toc-link:hover, .toc-link.active { background: var(--primary-light); color: var(--primary); border-left-color: var(--primary); }

/* Page Content */
.page-content { min-width: 0; }

/* Breadcrumb */
.breadcrumb { margin-bottom: 16px; overflow-x: auto; white-space: nowrap; -webkit-overflow-scrolling: touch; }
.breadcrumb::-webkit-scrollbar { display: none; }
.breadcrumb ol { list-style: none; display: flex; gap: 8px; font-size: 14px; }
.breadcrumb li { display: flex; align-items: center; gap: 8px; flex-shrink: 0; }
.breadcrumb li:not(:last-child)::after { content: '/'; color: var(--text-secondary); }
.breadcrumb a { color: var(--text-secondary); text-decoration: none; }
.breadcrumb a:hover { color: var(--primary); }
.breadcrumb [aria-current] { color: var(--text-primary); font-weight: 500; }

/* Page Header */
.page-header { margin-bottom: 24px; }
.page-title { font-size: 24px; font-weight: 800; margin-bottom: 8px; line-height: 1.2; }
@media (min-width: 640px) { .page-title { font-size: 32px; } }
.page-description { color: var(--text-secondary); font-size: 15px; }

/* ==================== CONTENT SECTION ==================== */
.content-section { background: var(--bg-card); border-radius: 16px; box-shadow: var(--shadow); margin-bottom: 24px; overflow: hidden; }
.section-header { padding: 16px 20px; border-bottom: 1px solid var(--border); display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 12px; }
@media (min-width: 640px) { .section-header { padding: 16px 24px; } }
.section-title { font-size: 16px; font-weight: 700; display: flex; align-items: center; gap: 8px; }
.section-icon { font-size: 18px; }
.section-body { padding: 20px; }
@media (min-width: 640px) { .section-body { padding: 24px; } }
.calculator-section { border: 2px solid var(--primary-light); }

/* ==================== FORM ELEMENTS ==================== */
.form-group { margin-bottom: 20px; }
.form-label { display: block; font-size: 14px; font-weight: 600; margin-bottom: 8px; }
.required { color: var(--error); margin-left: 2px; }
.form-input, .form-select { 
    width: 100%; 
    height: 48px; 
    padding: 0 16px; 
    border: 2px solid var(--border); 
    border-radius: 10px; 
    background: var(--bg-card); 
    color: var(--text-primary); 
    font-size: 16px;
    transition: all 0.2s; 
}
.form-input:focus, .form-select:focus { outline: none; border-color: var(--primary); box-shadow: 0 0 0 3px rgba(79,70,229,0.2); }
.form-input.error { border-color: var(--error); background: #fef2f2; }
.form-input::placeholder { color: var(--text-secondary); }
.form-hint { font-size: 12px; color: var(--text-secondary); margin-top: 4px; }
.form-error { font-size: 12px; color: var(--error); margin-top: 4px; min-height: 18px; display: block; }
.form-select { 
    cursor: pointer; 
    appearance: none; 
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='20' height='20' fill='%2364748b'%3E%3Cpath d='M7 10l5 5 5-5z'/%3E%3C/svg%3E"); 
    background-repeat: no-repeat; 
    background-position: right 12px center; 
    padding-right: 40px; 
}
.form-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 24px; }

/* ==================== BUTTONS ==================== */
.btn { 
    display: inline-flex; 
    align-items: center; 
    justify-content: center; 
    gap: 8px; 
    height: 48px; 
    padding: 0 20px; 
    border: 2px solid transparent; 
    border-radius: 10px; 
    font-size: 15px; 
    font-weight: 600; 
    cursor: pointer; 
    transition: all 0.2s; 
    white-space: nowrap;
}
.btn-primary { flex: 1; min-width: 140px; background: linear-gradient(135deg, var(--primary), var(--primary-dark)); color: white; }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 4px 12px rgba(79,70,229,0.4); }
.btn-secondary { background: var(--bg-card); border-color: var(--border); color: var(--text-secondary); }
.btn-secondary:hover { border-color: var(--primary); color: var(--primary); }
.btn-sm { height: 36px; padding: 0 12px; font-size: 13px; }
.btn-ghost { background: transparent; border: none; color: var(--text-secondary); height: 36px; padding: 0 10px; }
.btn-ghost:hover { background: var(--primary-light); color: var(--primary); }
.btn-icon-only { width: 40px; height: 40px; padding: 0; border: 1px solid rgba(255,255,255,0.3); border-radius: 8px; background: rgba(255,255,255,0.2); color: white; font-size: 16px; cursor: pointer; }
.btn-icon-only:hover { background: rgba(255,255,255,0.3); }

/* ==================== RESULT CARD ==================== */
.result-card { margin-top: 24px; background: linear-gradient(135deg, var(--primary), var(--primary-dark)); color: white; border-radius: 16px; overflow: hidden; }
.result-card[hidden] { display: none; }
.result-card .card-header { padding: 14px 20px; background: rgba(255,255,255,0.1); border-bottom: 1px solid rgba(255,255,255,0.2); display: flex; justify-content: space-between; align-items: center; }
.result-card .card-title { font-size: 15px; font-weight: 600; }
.result-card .card-body { padding: 20px; }
@media (min-width: 640px) { .result-card .card-body { padding: 24px; } }
.result-display { text-align: center; padding: 12px 0; }
.result-value { font-size: 48px; font-weight: 800; font-family: ui-monospace, monospace; }
@media (min-width: 640px) { .result-value { font-size: 64px; } }
.result-symbol { font-size: 20px; opacity: 0.8; margin-left: 4px; }
@media (min-width: 640px) { .result-symbol { font-size: 24px; } }
.result-actions { display: flex; gap: 8px; }
.result-meta { text-align: center; padding-top: 16px; border-top: 1px solid rgba(255,255,255,0.2); margin-top: 16px; }
.result-formula { font-family: monospace; font-size: 14px; opacity: 0.9; margin-bottom: 8px; word-break: break-all; }
.result-grade { font-size: 15px; font-weight: 600; }

/* ==================== STEPS ==================== */
.steps-list { display: flex; flex-direction: column; gap: 20px; }
.step-item { display: flex; gap: 16px; }
.step-number { flex-shrink: 0; width: 32px; height: 32px; display: flex; align-items: center; justify-content: center; background: var(--primary); color: white; border-radius: 50%; font-weight: 700; font-size: 14px; }
.step-title { font-weight: 600; margin-bottom: 4px; font-size: 15px; }
.step-text { font-size: 14px; color: var(--text-secondary); }

/* ==================== FORMULA BOX ==================== */
.formula-box { background: var(--primary-light); border: 2px solid var(--primary); border-radius: 12px; padding: 20px; text-align: center; margin-bottom: 20px; }
.formula-label { font-size: 11px; font-weight: 700; color: var(--text-secondary); text-transform: uppercase; letter-spacing: 0.05em; margin-bottom: 8px; }
.formula-display { font-size: 16px; font-weight: 700; }
@media (min-width: 640px) { .formula-display { font-size: 20px; } }
.formula-display code { font-family: monospace; background: var(--bg-card); padding: 8px 12px; border-radius: 6px; display: inline-block; word-break: break-all; }
.formula-explanation { font-size: 14px; color: var(--text-secondary); line-height: 1.7; }

/* ==================== EXAMPLES TABLE ==================== */
.examples-table-wrapper { overflow-x: auto; margin: 0 -20px; padding: 0 20px; -webkit-overflow-scrolling: touch; }
@media (min-width: 640px) { .examples-table-wrapper { margin: 0; padding: 0; } }
.examples-table { width: 100%; min-width: 320px; border-collapse: collapse; font-size: 13px; }
@media (min-width: 640px) { .examples-table { font-size: 14px; } }
.examples-table th, .examples-table td { padding: 10px 8px; text-align: center; border-bottom: 1px solid var(--border); }
@media (min-width: 640px) { .examples-table th, .examples-table td { padding: 10px 12px; } }
.examples-table th { background: var(--primary); color: white; font-size: 11px; font-weight: 600; white-space: nowrap; }
@media (min-width: 640px) { .examples-table th { font-size: 12px; } }
.examples-table tbody tr:hover { background: var(--primary-light); }
.examples-table td { font-family: monospace; font-size: 12px; }
@media (min-width: 640px) { .examples-table td { font-size: 14px; } }

/* ==================== FAQ ==================== */
.faq-list { display: flex; flex-direction: column; gap: 8px; }
.faq-item { border: 1px solid var(--border); border-radius: 10px; overflow: hidden; }
.faq-trigger { display: flex; justify-content: space-between; align-items: center; width: 100%; padding: 14px 16px; border: none; background: var(--bg-card); color: var(--text-primary); font-size: 14px; font-weight: 600; text-align: left; cursor: pointer; gap: 12px; }
.faq-trigger:hover { background: var(--primary-light); }
.faq-trigger span:first-child { flex: 1; }
.faq-chevron { font-size: 12px; color: var(--text-secondary); transition: transform 0.2s; flex-shrink: 0; }
.faq-trigger[aria-expanded="true"] .faq-chevron { transform: rotate(180deg); }
.faq-content { max-height: 0; overflow: hidden; transition: max-height 0.3s ease; }
.faq-content.open { max-height: 500px; }
.faq-body { padding: 14px 16px; font-size: 14px; color: var(--text-secondary); line-height: 1.7; border-top: 1px solid var(--border); }

/* ==================== FOOTER ==================== */
.site-footer { background: var(--bg-card); border-top: 1px solid var(--border); margin-top: 48px; }
.footer-container { max-width: 1200px; margin: 0 auto; padding: 40px 16px 24px; }
.footer-grid { display: grid; gap: 32px; margin-bottom: 32px; }
@media (min-width: 640px) { .footer-grid { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 900px) { .footer-grid { grid-template-columns: 1.5fr 1fr 1fr 1fr; } }

.footer-brand { }
.footer-brand-title { display: flex; align-items: center; gap: 8px; font-size: 18px; font-weight: 700; margin-bottom: 12px; }
.footer-brand-title span { font-size: 24px; }
.footer-brand-desc { font-size: 14px; color: var(--text-secondary); line-height: 1.6; margin-bottom: 16px; }
.footer-social { display: flex; gap: 8px; }
.footer-social-link { width: 36px; height: 36px; display: flex; align-items: center; justify-content: center; background: var(--primary-light); border-radius: 8px; text-decoration: none; font-size: 18px; transition: all 0.2s; }
.footer-social-link:hover { background: var(--primary); transform: translateY(-2px); }

.footer-section { }
.footer-section-title { font-size: 13px; font-weight: 700; text-transform: uppercase; letter-spacing: 0.05em; margin-bottom: 16px; color: var(--text-primary); }
.footer-links { list-style: none; }
.footer-links li { margin-bottom: 8px; }
.footer-link { display: inline-flex; align-items: center; gap: 6px; color: var(--text-secondary); text-decoration: none; font-size: 14px; transition: color 0.2s; }
.footer-link:hover { color: var(--primary); }
.footer-link .link-icon { font-size: 14px; }

.footer-bottom { display: flex; flex-direction: column; align-items: center; gap: 12px; padding-top: 24px; border-top: 1px solid var(--border); text-align: center; }
@media (min-width: 640px) { .footer-bottom { flex-direction: row; justify-content: space-between; } }
.footer-copyright { font-size: 13px; color: var(--text-secondary); }
.footer-bottom-links { display: flex; gap: 16px; flex-wrap: wrap; justify-content: center; }
.footer-bottom-link { font-size: 13px; color: var(--text-secondary); text-decoration: none; }
.footer-bottom-link:hover { color: var(--primary); }

/* ==================== ANIMATIONS ==================== */
@keyframes fadeInUp { from { opacity: 0; transform: translateY(20px); } to { opacity: 1; transform: translateY(0); } }
@keyframes shake { 0%, 100% { transform: translateX(0); } 20%, 60% { transform: translateX(-5px); } 40%, 80% { transform: translateX(5px); } }
.error { animation: shake 0.4s ease; }

/* ==================== PRINT ==================== */
@media print {
    .site-header, .site-footer, .page-sidebar, .form-actions, .btn-icon-only, .no-print, .mobile-nav { display: none !important; }
    .result-card { background: #f5f5f5 !important; color: #000 !important; box-shadow: none; border: 2px solid #000; }
    .result-card * { color: #000 !important; }
    body { background: white; }
    .page-wrapper { padding: 0; }
}

/* ==================== UTILITIES ==================== */
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); border: 0; }