/* SSL Checker Specific Styles - Premium Design with WebsiteTool.org Palette */

/* Smooth Scrolling */
html {
    scroll-behavior: smooth;
    scroll-padding-top: var(--space-20);
}

:root {
    /* WebsiteTool.org Color Palette */
    --color-primary: #161032;           /* Deep navy - primary dark */
    --color-accent-yellow: #FAFF81;     /* Bright lime yellow */
    --color-accent-amber: #FFC53A;      /* Golden amber */
    --color-accent-orange: #E06D06;     /* Bright orange */
    --color-accent-brown: #B26700;      /* Dark golden brown */

    /* Semantic Colors */
    --color-success: #10B981;
    --color-warning: var(--color-accent-orange);
    --color-error: #EF4444;

    /* Typography Colors */
    --color-text: #161032;
    --color-text-light: #6B7280;
    --color-text-muted: #9CA3AF;

    /* Background Colors */
    --color-bg: #FFFFFF;
    --color-bg-alt: #FAFAFA;
    --color-bg-section: #F9FAFB;

    /* Border Colors */
    --color-border: #E5E7EB;
    --color-border-light: #F3F4F6;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(22, 16, 50, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(22, 16, 50, 0.1), 0 2px 4px -1px rgba(22, 16, 50, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(22, 16, 50, 0.1), 0 4px 6px -2px rgba(22, 16, 50, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(22, 16, 50, 0.1), 0 10px 10px -5px rgba(22, 16, 50, 0.04);

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;

    /* Premium Typography Scale */
    --font-size-xs: 0.75rem;        /* 12px */
    --font-size-sm: 0.875rem;       /* 14px */
    --font-size-base: 1rem;         /* 16px */
    --font-size-lg: 1.125rem;       /* 18px */
    --font-size-xl: 1.25rem;        /* 20px */
    --font-size-2xl: 1.5rem;        /* 24px */
    --font-size-3xl: 1.875rem;      /* 30px */
    --font-size-4xl: 2.25rem;       /* 36px */

    /* Premium Spacing Scale */
    --space-1: 0.25rem;    /* 4px */
    --space-2: 0.5rem;     /* 8px */
    --space-3: 0.75rem;    /* 12px */
    --space-4: 1rem;       /* 16px */
    --space-5: 1.25rem;    /* 20px */
    --space-6: 1.5rem;     /* 24px */
    --space-8: 2rem;       /* 32px */
    --space-10: 2.5rem;    /* 40px */
    --space-12: 3rem;      /* 48px */
    --space-16: 4rem;      /* 64px */
    --space-20: 5rem;      /* 80px */
    --space-24: 6rem;      /* 96px */
}

/* Header Styles */
.header {
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
    background: rgba(255, 255, 255, 0.95);
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav__logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-text);
    text-decoration: none;
    transition: opacity 0.2s;
}

.nav__logo:hover {
    opacity: 0.8;
}

.nav__link {
    color: var(--color-primary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s;
}

.nav__link:hover {
    color: var(--color-primary-dark);
}

/* Hero Section */
.hero {
    text-align: center;
    padding: 3rem 0 2rem;
}

.hero__title {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--color-text);
    margin: 0 0 1rem;
    line-height: 1.2;
}

.hero__subtitle {
    font-size: 1.125rem;
    color: var(--color-text-light);
    max-width: 42rem;
    margin: 0 auto;
    line-height: 1.6;
}

/* Checker Section */
.checker-section {
    margin: 2rem 0;
}

.checker-card {
    background: var(--color-bg);
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
    padding: 2rem;
    max-width: 48rem;
    margin: 0 auto;
}

/* Form Styles */
.ssl-form {
    width: 100%;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-label {
    font-weight: 600;
    color: var(--color-text);
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.input-wrapper {
    display: flex;
    gap: 0.75rem;
}

.form-input {
    flex: 1;
    padding: 0.75rem 1rem;
    font-size: 1rem;
    border: 2px solid var(--color-border);
    border-radius: var(--radius);
    transition: border-color 0.2s, box-shadow 0.2s;
    font-family: inherit;
}

.form-input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.form-input::placeholder {
    color: #9CA3AF;
}

.form-help {
    color: var(--color-text-light);
    font-size: 0.875rem;
}

/* Button Styles */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    border: none;
    border-radius: var(--radius);
    cursor: pointer;
    transition: all 0.2s;
    font-family: inherit;
    text-decoration: none;
}

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

.btn--primary:hover {
    background: var(--color-primary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn--primary:active {
    transform: translateY(0);
}

.btn--primary:disabled {
    background: #9CA3AF;
    cursor: not-allowed;
    transform: none;
}

.btn--secondary {
    background: white;
    color: var(--color-primary);
    border: 2px solid var(--color-primary);
}

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

.btn__icon {
    width: 20px;
    height: 20px;
}

/* Loading Section */
.loading-section {
    max-width: 32rem;
    margin: 3rem auto;
}

.loading-card {
    background: var(--color-bg);
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
    padding: 3rem 2rem;
    text-align: center;
}

.spinner {
    width: 48px;
    height: 48px;
    border: 4px solid var(--color-border);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 1.5rem;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading-text {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--color-text);
    margin: 0 0 0.5rem;
}

.loading-subtext {
    color: var(--color-text-light);
    margin: 0;
}

/* Error Section */
.error-section {
    max-width: 32rem;
    margin: 3rem auto;
}

.error-card {
    background: var(--color-bg);
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
    padding: 3rem 2rem;
    text-align: center;
}

.error-icon {
    margin: 0 auto 1.5rem;
    color: var(--color-error);
}

.error-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-text);
    margin: 0 0 0.75rem;
}

.error-message {
    color: var(--color-text-light);
    margin: 0 0 1.5rem;
    line-height: 1.6;
}

/* Results Section */
.results-section {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    margin: 2rem 0;
    max-width: 56rem;
    margin-left: auto;
    margin-right: auto;
}

.result-card {
    background: var(--color-bg);
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
    padding: 2rem;
}

.result-card__title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-text);
    margin: 0 0 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid var(--color-border);
}

/* Status Card */
.status-card {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.status-card.status--valid {
    background: linear-gradient(135deg, #10B981 0%, #059669 100%);
}

.status-card.status--warning {
    background: linear-gradient(135deg, #F59E0B 0%, #D97706 100%);
}

.status-card.status--error {
    background: linear-gradient(135deg, #EF4444 0%, #DC2626 100%);
}

.status-header {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.status-icon-wrapper {
    flex-shrink: 0;
}

.status-icon {
    color: white;
}

.status-content {
    flex: 1;
}

.status-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin: 0 0 0.5rem;
    color: white;
}

.status-domain {
    font-size: 1rem;
    margin: 0;
    opacity: 0.9;
    font-family: 'Courier New', monospace;
}

.status-grade {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid rgba(255, 255, 255, 0.2);
}

.grade-label {
    font-weight: 600;
}

.grade-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 3rem;
    padding: 0.5rem 1rem;
    background: white;
    color: var(--color-primary);
    font-size: 1.5rem;
    font-weight: 800;
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
}

/* Info Grid */
.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.info-item {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.info-item--full {
    grid-column: 1 / -1;
}

.info-label {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--color-text-light);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.info-value {
    font-size: 1rem;
    color: var(--color-text);
    word-break: break-word;
}

.info-value--mono {
    font-family: 'Courier New', monospace;
    font-size: 0.875rem;
}

.info-value.value--success {
    color: var(--color-success);
    font-weight: 600;
}

.info-value.value--warning {
    color: var(--color-warning);
    font-weight: 600;
}

.info-value.value--error {
    color: var(--color-error);
    font-weight: 600;
}

/* Actions */
.actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-top: 1rem;
}

/* Info Section */
.info-section {
    margin: 4rem 0 3rem;
}

.info-section__title {
    font-size: 2rem;
    font-weight: 700;
    text-align: center;
    margin: 0 0 2rem;
    color: var(--color-text);
}

.info-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.info-card {
    background: var(--color-bg-alt);
    border-radius: var(--radius);
    padding: 1.5rem;
    border: 1px solid var(--color-border);
}

.info-card__title {
    font-size: 1.125rem;
    font-weight: 700;
    color: var(--color-text);
    margin: 0 0 0.75rem;
}

.info-card__text {
    color: var(--color-text-light);
    line-height: 1.6;
    margin: 0;
}

/* Footer */
.footer {
    background: var(--color-bg-alt);
    border-top: 1px solid var(--color-border);
    padding: 2rem 0;
    margin-top: 4rem;
    text-align: center;
    color: var(--color-text-light);
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero__title {
        font-size: 2rem;
    }

    .hero__subtitle {
        font-size: 1rem;
    }

    .checker-card {
        padding: 1.5rem;
    }

    .input-wrapper {
        flex-direction: column;
    }

    .status-header {
        flex-direction: column;
        text-align: center;
    }

    .status-grade {
        justify-content: center;
    }

    .info-grid {
        grid-template-columns: 1fr;
    }

    .result-card {
        padding: 1.5rem;
    }
}

@media (max-width: 480px) {
    .hero {
        padding: 2rem 0 1.5rem;
    }

    .hero__title {
        font-size: 1.75rem;
    }

    .checker-card {
        padding: 1rem;
    }

    .result-card {
        padding: 1rem;
    }

    .actions {
        flex-direction: column;
    }

    .btn {
        width: 100%;
    }
}

/* Table of Contents - Sticky Navigation */
.table-of-contents {
    position: sticky;
    top: var(--space-8);
    background: linear-gradient(135deg, var(--color-primary) 0%, #1a1440 100%);
    border-radius: var(--radius-xl);
    padding: var(--space-6);
    margin: var(--space-12) auto;
    max-width: 56rem;
    box-shadow: var(--shadow-xl);
    z-index: 50;
}

.toc-title {
    font-size: var(--font-size-lg);
    font-weight: 700;
    color: var(--color-accent-yellow);
    margin: 0 0 var(--space-4);
    letter-spacing: -0.02em;
    display: flex;
    align-items: center;
    gap: var(--space-3);
}

.toc-title::before {
    content: '📑';
    font-size: var(--font-size-2xl);
}

.toc-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--space-2);
    list-style: none;
    margin: 0;
    padding: 0;
}

.toc-item a {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-4);
    color: white;
    text-decoration: none;
    border-radius: var(--radius);
    transition: all 0.2s;
    font-size: var(--font-size-sm);
    font-weight: 500;
    background: rgba(255, 255, 255, 0.05);
}

.toc-item a:hover {
    background: rgba(255, 255, 255, 0.15);
    transform: translateX(4px);
}

.toc-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 24px;
    height: 24px;
    background: var(--color-accent-amber);
    color: var(--color-primary);
    border-radius: 50%;
    font-size: var(--font-size-xs);
    font-weight: 700;
    flex-shrink: 0;
}

/* Premium Content Sections */
.content-section {
    max-width: 56rem;
    margin: var(--space-16) auto;
    padding: 0 var(--space-4);
    scroll-margin-top: var(--space-20);
}

.content-section__title {
    font-size: var(--font-size-3xl);
    font-weight: 800;
    color: var(--color-text);
    margin: 0 0 var(--space-8);
    line-height: 1.2;
    letter-spacing: -0.03em;
    position: relative;
    padding-bottom: var(--space-4);
}

.content-section__title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 80px;
    height: 4px;
    background: linear-gradient(90deg, var(--color-accent-amber) 0%, var(--color-accent-orange) 100%);
    border-radius: 2px;
}

.content-subtitle {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--color-text);
    margin: var(--space-10) 0 var(--space-4);
    line-height: 1.3;
    letter-spacing: -0.02em;
    display: flex;
    align-items: center;
    gap: var(--space-3);
}

.content-subtitle::before {
    content: '';
    width: 6px;
    height: 32px;
    background: var(--color-accent-amber);
    border-radius: 3px;
    flex-shrink: 0;
}

.content-rich {
    font-size: var(--font-size-lg);
    line-height: 1.8;
    color: var(--color-text);
}

.content-rich > p {
    margin-bottom: var(--space-6);
}

.content-lead {
    font-size: var(--font-size-xl);
    font-weight: 500;
    line-height: 1.6;
    color: var(--color-text);
    margin-bottom: var(--space-8);
    padding: var(--space-6);
    background: linear-gradient(135deg, rgba(255, 197, 58, 0.08) 0%, rgba(224, 109, 6, 0.08) 100%);
    border-left: 4px solid var(--color-accent-amber);
    border-radius: 0 var(--radius-lg) var(--radius-lg) 0;
    position: relative;
    overflow: hidden;
}

.content-lead::before {
    content: '💡';
    position: absolute;
    top: var(--space-2);
    right: var(--space-4);
    font-size: var(--font-size-4xl);
    opacity: 0.1;
}

.content-list {
    margin: var(--space-6) 0;
    padding: 0 0 0 var(--space-6);
}

.content-list li {
    margin: var(--space-4) 0;
    line-height: 1.8;
    position: relative;
    padding-left: var(--space-2);
}

.content-list li::marker {
    color: var(--color-accent-amber);
    font-weight: 700;
}

.content-list li strong {
    color: var(--color-text);
    font-weight: 600;
}

.content-link {
    color: var(--color-accent-orange);
    text-decoration: none;
    border-bottom: 2px solid transparent;
    transition: all 0.2s;
    font-weight: 500;
}

.content-link:hover {
    border-bottom-color: var(--color-accent-orange);
    color: var(--color-accent-brown);
}

/* Premium Section Variants */
.content-section--highlight {
    background: linear-gradient(135deg, rgba(250, 255, 129, 0.05) 0%, rgba(255, 197, 58, 0.08) 100%);
    padding: var(--space-12) var(--space-8);
    border-radius: var(--radius-xl);
    border: 2px solid var(--color-accent-yellow);
    border-left-width: 6px;
    box-shadow: var(--shadow-lg);
    position: relative;
    overflow: hidden;
}

.content-section--highlight::before {
    content: '⭐';
    position: absolute;
    top: var(--space-6);
    right: var(--space-6);
    font-size: 4rem;
    opacity: 0.08;
}

.content-section--practical {
    background: var(--color-bg-section);
    padding: var(--space-12) var(--space-8);
    border-radius: var(--radius-xl);
    border-left: 6px solid var(--color-accent-orange);
}

.content-section--seo {
    background: white;
    border: 3px solid var(--color-accent-amber);
    padding: var(--space-12) var(--space-8);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    position: relative;
}

.content-section--seo::before {
    content: '🚀';
    position: absolute;
    top: var(--space-6);
    right: var(--space-6);
    font-size: 3rem;
    opacity: 0.1;
}

.content-section--examples {
    background: white;
    position: relative;
}

.content-section--comparison {
    background: linear-gradient(180deg, white 0%, var(--color-bg-section) 100%);
    padding: var(--space-12) var(--space-8);
    border-radius: var(--radius-xl);
}

/* Premium Error Fix Cards */
.error-fix-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: var(--space-6);
    margin-top: var(--space-8);
}

.error-fix-card {
    background: white;
    border: 2px solid var(--color-border-light);
    border-left: 5px solid var(--color-error);
    border-radius: var(--radius-lg);
    padding: var(--space-6);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
}

.error-fix-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--color-error) 0%, var(--color-accent-orange) 100%);
    opacity: 0;
    transition: opacity 0.3s;
}

.error-fix-card:hover {
    border-color: var(--color-accent-amber);
    box-shadow: var(--shadow-lg);
    transform: translateY(-4px);
}

.error-fix-card:hover::before {
    opacity: 1;
}

.error-fix-title {
    font-size: var(--font-size-lg);
    font-weight: 700;
    color: var(--color-text);
    margin: 0 0 var(--space-4);
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.error-fix-card p {
    margin: var(--space-3) 0;
    line-height: 1.7;
}

.error-fix-card p strong {
    color: var(--color-primary);
    font-weight: 600;
}

.fix-steps {
    margin: var(--space-4) 0 0 var(--space-5);
    padding: 0;
}

.fix-steps li {
    margin: var(--space-3) 0;
    line-height: 1.7;
    position: relative;
}

.fix-steps li::marker {
    color: var(--color-accent-amber);
    font-weight: 700;
}

.error-fix-card code {
    background: linear-gradient(135deg, rgba(255, 197, 58, 0.1) 0%, rgba(224, 109, 6, 0.05) 100%);
    padding: var(--space-1) var(--space-3);
    border-radius: var(--radius-sm);
    font-family: 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'Courier New', monospace;
    font-size: var(--font-size-sm);
    color: var(--color-accent-brown);
    border: 1px solid rgba(255, 197, 58, 0.2);
    font-weight: 500;
}

/* Premium Example Cards */
.example-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: var(--space-6);
    margin-top: var(--space-8);
}

.example-card {
    background: linear-gradient(135deg, white 0%, var(--color-bg-alt) 100%);
    border-radius: var(--radius-xl);
    padding: var(--space-8);
    border: 2px solid var(--color-border);
    border-top: 4px solid var(--color-accent-amber);
    box-shadow: var(--shadow-md);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
}

.example-card::before {
    content: '📘';
    position: absolute;
    top: var(--space-4);
    right: var(--space-4);
    font-size: var(--font-size-3xl);
    opacity: 0.1;
}

.example-card:hover {
    border-color: var(--color-accent-amber);
    box-shadow: var(--shadow-xl);
    transform: translateY(-2px);
}

.example-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-text);
    margin: 0 0 var(--space-4);
    letter-spacing: -0.01em;
}

.example-scenario {
    font-style: italic;
    color: var(--color-text-light);
    margin-bottom: var(--space-4);
    padding: var(--space-3) var(--space-4);
    background: rgba(255, 197, 58, 0.08);
    border-left: 3px solid var(--color-accent-amber);
    border-radius: var(--radius);
    font-size: var(--font-size-sm);
}

.example-card > p {
    margin: var(--space-4) 0;
    line-height: 1.7;
}

.example-card > p strong {
    color: var(--color-primary);
    font-weight: 600;
}

.example-list {
    margin: var(--space-4) 0;
    padding-left: var(--space-5);
}

.example-list li {
    margin: var(--space-3) 0;
    line-height: 1.7;
}

.example-list li::marker {
    color: var(--color-accent-amber);
    font-weight: 600;
}

.example-list li strong {
    color: var(--color-primary);
    font-weight: 600;
}

/* Premium Comparison Table */
.comparison-table-wrapper {
    overflow-x: auto;
    margin: var(--space-8) 0;
    border-radius: var(--radius-xl);
    border: 2px solid var(--color-border);
    box-shadow: var(--shadow-lg);
    background: white;
}

.comparison-table {
    width: 100%;
    border-collapse: collapse;
    background: white;
}

.comparison-table thead {
    background: linear-gradient(135deg, var(--color-primary) 0%, #1a1440 100%);
    color: white;
}

.comparison-table th,
.comparison-table td {
    padding: var(--space-4) var(--space-5);
    text-align: left;
    border-bottom: 1px solid var(--color-border-light);
}

.comparison-table th {
    font-weight: 700;
    font-size: var(--font-size-sm);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-accent-yellow);
}

.comparison-table tbody tr {
    transition: background-color 0.2s;
}

.comparison-table tbody tr:hover {
    background: linear-gradient(90deg, rgba(255, 197, 58, 0.05) 0%, transparent 100%);
}

.comparison-table tbody tr:last-child td {
    border-bottom: none;
}

.comparison-table td strong {
    color: var(--color-primary);
    font-weight: 700;
}

/* Premium Validation Type Cards */
.validation-types {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--space-6);
    margin-top: var(--space-8);
}

.validation-card {
    background: white;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--space-6);
    transition: all 0.3s;
    position: relative;
    overflow: hidden;
}

.validation-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: linear-gradient(180deg, var(--color-accent-amber) 0%, var(--color-accent-orange) 100%);
    transform: scaleY(0);
    transform-origin: top;
    transition: transform 0.3s;
}

.validation-card:hover {
    border-color: var(--color-accent-amber);
    box-shadow: var(--shadow-lg);
}

.validation-card:hover::before {
    transform: scaleY(1);
}

.validation-card h4 {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-primary);
    margin: 0 0 var(--space-4);
    letter-spacing: -0.01em;
}

.validation-card p {
    margin: var(--space-2) 0;
    line-height: 1.7;
    font-size: var(--font-size-base);
}

.validation-card p strong {
    color: var(--color-primary);
    font-weight: 600;
}

/* Premium FAQ Section */
.faq-section {
    max-width: 56rem;
    margin: var(--space-16) auto;
    padding: 0 var(--space-4);
}

.faq-section__header {
    text-align: center;
    margin-bottom: var(--space-12);
}

.faq-section__title {
    font-size: var(--font-size-3xl);
    font-weight: 800;
    color: var(--color-text);
    margin: 0 0 var(--space-4);
    letter-spacing: -0.03em;
}

.faq-section__subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-text-light);
    margin: 0;
}

.faq-container {
    display: flex;
    flex-direction: column;
    gap: var(--space-4);
}

.faq-item {
    background: white;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: all 0.3s;
    box-shadow: var(--shadow-sm);
}

.faq-item:hover {
    border-color: var(--color-accent-amber);
    box-shadow: var(--shadow-md);
}

.faq-question {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--space-4);
    padding: var(--space-5) var(--space-6);
    background: none;
    border: none;
    text-align: left;
    cursor: pointer;
    transition: background-color 0.2s;
    font-family: inherit;
}

.faq-question:hover {
    background: linear-gradient(90deg, rgba(255, 197, 58, 0.05) 0%, transparent 100%);
}

.faq-question[aria-expanded="true"] {
    background: linear-gradient(135deg, rgba(255, 197, 58, 0.1) 0%, rgba(224, 109, 6, 0.05) 100%);
    border-bottom: 1px solid var(--color-border-light);
}

.faq-question-text {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--color-text);
    line-height: 1.5;
}

.faq-icon {
    width: 28px;
    height: 28px;
    flex-shrink: 0;
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    color: var(--color-accent-amber);
}

.faq-question[aria-expanded="true"] .faq-icon {
    transform: rotate(180deg);
    color: var(--color-accent-orange);
}

.faq-answer {
    display: none;
    overflow: hidden;
}

.faq-answer.active {
    display: block;
    animation: fadeIn 0.3s ease-in-out;
}

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

.faq-answer-content {
    padding: 0 var(--space-6) var(--space-6) var(--space-6);
    color: var(--color-text);
    line-height: 1.8;
    font-size: var(--font-size-base);
}

.faq-answer-content p {
    margin: 0 0 var(--space-4);
}

.faq-answer-content p:last-child {
    margin-bottom: 0;
}

.faq-answer-content ul,
.faq-answer-content ol {
    margin: var(--space-4) 0;
    padding-left: var(--space-6);
}

.faq-answer-content li {
    margin: var(--space-2) 0;
}

.faq-answer-content li::marker {
    color: var(--color-accent-amber);
}

.faq-answer-content strong {
    color: var(--color-primary);
    font-weight: 600;
}

/* Footer Grid */
.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    max-width: 1200px;
    margin: 0 auto 2rem;
    text-align: left;
}

.footer-section__title {
    font-size: 1rem;
    font-weight: 700;
    color: var(--color-text);
    margin: 0 0 1rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.footer-links {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer-links li {
    margin: 0.5rem 0;
}

.footer-links a {
    color: var(--color-text-light);
    text-decoration: none;
    transition: color 0.2s;
}

.footer-links a:hover {
    color: var(--color-primary);
}

.footer-bottom {
    padding-top: 2rem;
    border-top: 1px solid var(--color-border);
    max-width: 1200px;
    margin: 0 auto;
}

.footer-bottom p {
    margin: 0.5rem 0;
}

.footer-meta {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.separator {
    color: var(--color-border);
}

/* Print Styles */
@media print {
    .header,
    .footer,
    .checker-section,
    .actions {
        display: none;
    }

    .results-section,
    .content-section,
    .faq-section {
        margin: 0;
        page-break-inside: avoid;
    }
}

/* Responsive Adjustments for Premium Sections */
@media (max-width: 768px) {
    /* Table of Contents */
    .table-of-contents {
        position: relative;
        top: 0;
    }

    .toc-list {
        grid-template-columns: 1fr;
    }

    /* Content Sections */
    .content-section {
        margin: var(--space-12) auto;
    }

    .content-section__title {
        font-size: var(--font-size-2xl);
    }

    .content-subtitle {
        font-size: var(--font-size-xl);
    }

    .content-lead {
        font-size: var(--font-size-lg);
        padding: var(--space-4);
    }

    .content-rich {
        font-size: var(--font-size-base);
    }

    /* Section Variants */
    .content-section--highlight,
    .content-section--practical,
    .content-section--seo,
    .content-section--comparison {
        padding: var(--space-8) var(--space-4);
    }

    /* Error Fix Cards */
    .error-fix-grid,
    .example-grid,
    .validation-types {
        grid-template-columns: 1fr;
    }

    /* Comparison Table */
    .comparison-table {
        font-size: var(--font-size-sm);
    }

    .comparison-table th,
    .comparison-table td {
        padding: var(--space-3) var(--space-2);
    }

    /* FAQ */
    .faq-question {
        padding: var(--space-4) var(--space-5);
    }

    .faq-question-text {
        font-size: var(--font-size-base);
    }

    .faq-answer-content {
        padding: 0 var(--space-5) var(--space-5) var(--space-5);
    }

    /* Footer */
    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 480px) {
    /* Table of Contents */
    .toc-title {
        font-size: var(--font-size-base);
    }

    .toc-item a {
        font-size: var(--font-size-xs);
        padding: var(--space-2) var(--space-3);
    }

    .toc-number {
        width: 20px;
        height: 20px;
        font-size: 10px;
    }

    /* Content Sections */
    .content-section {
        margin: var(--space-8) auto;
    }

    .content-section__title {
        font-size: var(--font-size-xl);
    }

    .content-subtitle {
        font-size: var(--font-size-lg);
        margin-top: var(--space-6);
    }

    .content-lead {
        font-size: var(--font-size-base);
        padding: var(--space-3);
    }

    /* Section Variants */
    .content-section--highlight,
    .content-section--practical,
    .content-section--seo,
    .content-section--comparison {
        padding: var(--space-6) var(--space-3);
    }

    /* Error Fix Cards */
    .error-fix-card,
    .example-card,
    .validation-card {
        padding: var(--space-4);
    }

    .error-fix-title,
    .example-title {
        font-size: var(--font-size-base);
    }

    /* FAQ */
    .faq-section__title {
        font-size: var(--font-size-2xl);
    }

    .faq-question {
        padding: var(--space-4);
    }

    .faq-question-text {
        font-size: var(--font-size-sm);
    }

    .faq-answer-content {
        padding: 0 var(--space-4) var(--space-4) var(--space-4);
        font-size: var(--font-size-sm);
    }

    /* Footer */
    .footer-grid {
        grid-template-columns: 1fr;
        gap: var(--space-6);
    }
}