/* ============================================
   CalcHub - Main Stylesheet
   Premium White & Blue Brand Design
   ============================================ */

/* CSS Variables */
:root {
    /* Brand Colors */
    --primary: #1a6ef5;
    --primary-dark: #0b5cd5;
    --primary-light: #4d8ff7;
    --primary-50: #eef4ff;
    --primary-100: #d9e7ff;
    --primary-200: #bcd4ff;
    --primary-300: #8eb8ff;
    --primary-400: #5996ff;
    --primary-500: #1a6ef5;
    --primary-600: #0b5cd5;
    --primary-700: #0a4ab3;
    --primary-800: #0d3d8f;
    --primary-900: #103571;

    /* Accent */
    --accent: #0ea5e9;
    --accent-light: #38bdf8;
    --accent-dark: #0284c7;

    /* Secondary (Dark) */
    --secondary: #0c1929;
    --secondary-light: #132640;

    /* Neutral Colors */
    --white: #ffffff;
    --gray-50: #f8fafc;
    --gray-100: #f1f5f9;
    --gray-200: #e2e8f0;
    --gray-300: #cbd5e1;
    --gray-400: #94a3b8;
    --gray-500: #64748b;
    --gray-600: #475569;
    --gray-700: #334155;
    --gray-800: #1e293b;
    --gray-900: #0f172a;

    /* Category Colors - all blue shades */
    --financial: #1a6ef5;
    --health: #06b6d4;
    --math: #6366f1;
    --conversion: #0ea5e9;
    --datetime: #3b82f6;
    --other: #8b5cf6;

    /* Status Colors */
    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;
    --info: #3b82f6;

    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.625rem;
    --radius-lg: 0.875rem;
    --radius-xl: 1.25rem;
    --radius-2xl: 1.5rem;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.04);
    --shadow-md: 0 4px 12px -2px rgb(0 0 0 / 0.06), 0 2px 4px -2px rgb(0 0 0 / 0.04);
    --shadow-lg: 0 12px 24px -4px rgb(0 0 0 / 0.08), 0 4px 8px -4px rgb(0 0 0 / 0.03);
    --shadow-xl: 0 20px 40px -8px rgb(0 0 0 / 0.1), 0 8px 16px -6px rgb(0 0 0 / 0.04);
    --shadow-blue: 0 4px 16px -2px rgba(26, 110, 245, 0.2);
    --shadow-blue-lg: 0 12px 32px -4px rgba(26, 110, 245, 0.25);

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 350ms ease;

    /* Container */
    --container-max: 1280px;
    --container-padding: 1rem;
}

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-primary);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--gray-800);
    background-color: var(--white);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.3;
    color: var(--gray-900);
    margin-bottom: var(--spacing-md);
}

h1 { font-size: 2.25rem; letter-spacing: -0.025em; }
h2 { font-size: 1.875rem; letter-spacing: -0.02em; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: var(--spacing-md);
}

a {
    color: var(--primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

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

code {
    background: var(--primary-50);
    color: var(--primary-700);
    padding: 0.15em 0.4em;
    border-radius: var(--radius-sm);
    font-size: 0.875em;
    font-family: var(--font-mono);
}

/* Container */
.container {
    width: 100%;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--container-padding);
}

/* ============================================
   Header
   ============================================ */
.header {
    background: var(--white);
    border-bottom: 1px solid var(--gray-100);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    background: rgba(255, 255, 255, 0.92);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
    gap: var(--spacing-lg);
}

/* Logo */
.logo {
    display: flex;
    align-items: center;
    gap: 0.625rem;
    font-size: 1.25rem;
    font-weight: 800;
    color: var(--gray-900);
    text-decoration: none;
    letter-spacing: -0.02em;
    flex-shrink: 0;
}

.logo-icon {
    width: 42px;
    height: 42px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--white);
    font-weight: 800;
    font-size: 1.25rem;
    box-shadow: var(--shadow-blue);
}

.logo span {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Search Bar */
.search-container {
    flex: 1;
    max-width: 480px;
    position: relative;
}

.search-box {
    position: relative;
    width: 100%;
}

.search-input {
    width: 100%;
    padding: 0.7rem 1rem 0.7rem 2.75rem;
    border: 1.5px solid var(--gray-200);
    border-radius: var(--radius-full);
    font-size: 0.9rem;
    font-family: var(--font-primary);
    background: var(--gray-50);
    transition: all var(--transition-fast);
    color: var(--gray-800);
}

.search-input:focus {
    outline: none;
    border-color: var(--primary-300);
    background: var(--white);
    box-shadow: 0 0 0 4px var(--primary-100);
}

.search-input::placeholder {
    color: var(--gray-400);
}

.search-icon {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--gray-400);
    pointer-events: none;
}

.search-results {
    position: absolute;
    top: calc(100% + 8px);
    left: 0;
    right: 0;
    background: var(--white);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    padding: var(--spacing-sm);
    z-index: 200;
    max-height: 400px;
    overflow-y: auto;
}

.search-result-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: 0.75rem 1rem;
    border-radius: var(--radius-lg);
    color: var(--gray-700);
    transition: all var(--transition-fast);
}

.search-result-item:hover {
    background: var(--primary-50);
    color: var(--primary);
}

.search-result-icon {
    width: 36px;
    height: 36px;
    background: var(--primary-50);
    color: var(--primary);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    flex-shrink: 0;
}

.search-result-content {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.search-result-content strong {
    font-size: 0.9rem;
}

.search-result-content span {
    font-size: 0.8rem;
    color: var(--gray-500);
}

.search-no-results {
    padding: 1.5rem;
    text-align: center;
    color: var(--gray-500);
    font-size: 0.9rem;
}

/* Navigation */
.nav-main {
    display: flex;
    align-items: center;
    gap: 2px;
}

.nav-link {
    padding: 0.5rem 0.875rem;
    color: var(--gray-600);
    font-weight: 500;
    font-size: 0.925rem;
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    gap: 4px;
    white-space: nowrap;
}

.nav-link:hover {
    color: var(--primary);
    background: var(--primary-50);
}

.nav-dropdown {
    position: relative;
}

.nav-dropdown-content {
    position: absolute;
    top: 100%;
    left: 0;
    background: var(--white);
    border: 1px solid var(--gray-100);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    padding: var(--spacing-sm);
    min-width: 240px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(8px);
    transition: all var(--transition-fast);
    z-index: 50;
}

.nav-dropdown:hover .nav-dropdown-content {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.nav-dropdown-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: 0.75rem 1rem;
    color: var(--gray-700);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
    font-size: 0.9rem;
}

.nav-dropdown-item:hover {
    background: var(--primary-50);
    color: var(--primary);
}

.nav-dropdown-icon {
    width: 34px;
    height: 34px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.95rem;
    font-weight: 600;
    background: var(--primary-50);
    color: var(--primary);
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    padding: var(--spacing-sm);
    cursor: pointer;
    color: var(--gray-700);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.mobile-menu-toggle:hover {
    background: var(--gray-100);
}

/* ============================================
   Main Content
   ============================================ */
main {
    flex: 1;
    padding: var(--spacing-xl) 0;
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
    text-align: center;
    padding: var(--spacing-3xl) var(--spacing-xl);
    background: linear-gradient(180deg, var(--primary-50) 0%, var(--white) 100%);
    border-radius: var(--radius-2xl);
    margin-bottom: var(--spacing-3xl);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(ellipse at 50% 0%, rgba(26, 110, 245, 0.06) 0%, transparent 60%);
    pointer-events: none;
}

.hero h1 {
    font-size: 2.75rem;
    margin-bottom: var(--spacing-md);
    position: relative;
    color: var(--gray-900);
}

.hero h1 span {
    background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero p {
    font-size: 1.15rem;
    color: var(--gray-500);
    max-width: 560px;
    margin: 0 auto var(--spacing-xl);
    line-height: 1.7;
    position: relative;
}

/* ============================================
   Category Cards
   ============================================ */
.categories-section {
    margin-bottom: var(--spacing-3xl);
}

.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--spacing-xl);
}

.section-title {
    font-size: 1.75rem;
    margin-bottom: 0;
    color: var(--gray-900);
}

.section-link {
    font-weight: 600;
    font-size: 0.925rem;
    display: flex;
    align-items: center;
    gap: 6px;
    color: var(--primary);
    padding: 0.5rem 1rem;
    border-radius: var(--radius-full);
    transition: all var(--transition-fast);
}

.section-link:hover {
    background: var(--primary-50);
}

.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.category-card {
    background: var(--white);
    border-radius: var(--radius-2xl);
    padding: var(--spacing-xl) var(--spacing-xl) var(--spacing-lg);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-normal);
    border: 1px solid var(--gray-100);
    position: relative;
    overflow: hidden;
}

.category-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    opacity: 0;
    transition: opacity var(--transition-normal);
}

.category-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
    border-color: var(--primary-100);
}

.category-card:hover::before {
    opacity: 1;
}

.category-icon {
    width: 52px;
    height: 52px;
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    color: var(--white);
}

.category-icon.financial { background: linear-gradient(135deg, #1a6ef5, #0b5cd5); }
.category-icon.health { background: linear-gradient(135deg, #06b6d4, #0891b2); }
.category-icon.math { background: linear-gradient(135deg, #6366f1, #4f46e5); }
.category-icon.conversion { background: linear-gradient(135deg, #0ea5e9, #0284c7); }
.category-icon.datetime { background: linear-gradient(135deg, #3b82f6, #2563eb); }
.category-icon.other { background: linear-gradient(135deg, #8b5cf6, #7c3aed); }

.category-card h3 {
    font-size: 1.2rem;
    margin-bottom: var(--spacing-sm);
    color: var(--gray-900);
}

.category-card p {
    color: var(--gray-500);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-md);
    line-height: 1.6;
}

.category-links {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.category-link {
    font-size: 0.85rem;
    color: var(--primary);
    padding: 0.3rem 0.85rem;
    background: var(--primary-50);
    border-radius: var(--radius-full);
    transition: all var(--transition-fast);
    font-weight: 500;
}

.category-link:hover {
    background: var(--primary);
    color: var(--white);
    box-shadow: var(--shadow-blue);
}

/* ============================================
   Category Page — Calculator Listing
   ============================================ */
.category-description {
    font-size: 1.05rem;
    color: var(--gray-600);
    line-height: 1.7;
    margin-bottom: var(--spacing-lg);
}

.category-grid {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-2xl);
}

.category-grid .category-card {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-lg) var(--spacing-xl);
    text-decoration: none;
    border-radius: var(--radius-xl);
    background: var(--white);
    border: 1px solid var(--gray-100);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-fast);
    position: relative;
    overflow: hidden;
}

.category-grid .category-card::before {
    display: none;
}

.category-grid .category-card:hover {
    transform: translateX(4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-100);
}

.category-card-icon {
    width: 48px;
    height: 48px;
    min-width: 48px;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.3rem;
    font-weight: 700;
}

.category-card-content {
    flex: 1;
    min-width: 0;
}

.category-card-content h2 {
    font-size: 1.05rem;
    font-weight: 600;
    color: var(--gray-900);
    margin: 0 0 0.2rem;
}

.category-card-content p {
    font-size: 0.88rem;
    color: var(--gray-500);
    margin: 0;
    line-height: 1.5;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.category-card-arrow {
    color: var(--gray-300);
    flex-shrink: 0;
    transition: color var(--transition-fast);
}

.category-grid .category-card:hover .category-card-arrow {
    color: var(--primary);
}

/* Cross-links to other categories */
.category-cross-links {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: var(--spacing-md);
}

.cross-link-card {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-lg);
    background: var(--gray-50);
    border: 1px solid var(--gray-100);
    text-decoration: none;
    transition: all var(--transition-fast);
}

.cross-link-card:hover {
    background: var(--white);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-100);
}

.cross-link-icon {
    font-size: 1.4rem;
    font-weight: 700;
    width: 36px;
    text-align: center;
}

.cross-link-card strong {
    display: block;
    font-size: 0.92rem;
    color: var(--gray-800);
}

.cross-link-card small {
    font-size: 0.8rem;
    color: var(--gray-400);
}

/* ============================================
   Popular Calculators
   ============================================ */
.popular-section {
    margin-bottom: var(--spacing-3xl);
}

.calculators-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: var(--spacing-md);
}

.calc-card {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--white);
    border-radius: var(--radius-xl);
    border: 1px solid var(--gray-100);
    transition: all var(--transition-fast);
}

.calc-card:hover {
    border-color: var(--primary-200);
    box-shadow: var(--shadow-blue);
    transform: translateY(-2px);
}

.calc-card-icon {
    width: 46px;
    height: 46px;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--primary-50);
    color: var(--primary);
    font-size: 1.15rem;
    font-weight: 700;
    flex-shrink: 0;
}

.calc-card-content h4 {
    font-size: 0.95rem;
    margin-bottom: 0.15rem;
    color: var(--gray-900);
}

.calc-card-content p {
    font-size: 0.8rem;
    color: var(--gray-500);
    margin: 0;
}

/* ============================================
   Features Section
   ============================================ */
.features-section {
    background: var(--white);
    border-radius: var(--radius-2xl);
    padding: var(--spacing-3xl);
    margin-bottom: var(--spacing-3xl);
    border: 1px solid var(--gray-100);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xl);
    margin-top: var(--spacing-xl);
}

.feature-item {
    text-align: center;
    padding: var(--spacing-lg);
    border-radius: var(--radius-xl);
    transition: all var(--transition-normal);
}

.feature-item:hover {
    background: var(--primary-50);
}

.feature-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto var(--spacing-md);
    background: var(--primary-50);
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: var(--primary);
    transition: all var(--transition-normal);
}

.feature-item:hover .feature-icon {
    background: var(--primary);
    color: var(--white);
    box-shadow: var(--shadow-blue);
}

.feature-item h4 {
    margin-bottom: var(--spacing-sm);
    font-size: 1.05rem;
}

.feature-item p {
    color: var(--gray-500);
    font-size: 0.9rem;
    margin: 0;
    line-height: 1.6;
}

/* ============================================
   Footer
   ============================================ */
.footer {
    background: var(--secondary);
    color: var(--gray-300);
    padding: var(--spacing-3xl) 0 var(--spacing-xl);
    margin-top: auto;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr repeat(3, 1fr);
    gap: var(--spacing-2xl);
    margin-bottom: var(--spacing-2xl);
}

.footer-brand .logo {
    margin-bottom: var(--spacing-sm);
}

.footer-brand .logo {
    color: var(--white);
}

.footer-brand .logo-icon {
    box-shadow: none;
}

.footer-brand p {
    margin-top: var(--spacing-md);
    color: var(--gray-400);
    max-width: 300px;
    font-size: 0.9rem;
    line-height: 1.7;
}

.footer-title {
    color: var(--white);
    font-size: 0.95rem;
    font-weight: 700;
    margin-bottom: var(--spacing-lg);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: 0.625rem;
}

.footer-links a {
    color: var(--gray-400);
    font-size: 0.9rem;
    transition: all var(--transition-fast);
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.footer-links a:hover {
    color: var(--white);
    padding-left: 4px;
}

.footer-bottom {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: var(--spacing-xl);
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    font-size: 0.875rem;
    color: var(--gray-500);
}

.footer-legal {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.footer-legal a {
    color: var(--gray-500);
    font-size: 0.875rem;
}

.footer-legal a:hover {
    color: var(--white);
    padding-left: 0;
}

.footer-legal span {
    color: var(--gray-700);
}

.footer-social {
    display: flex;
    gap: var(--spacing-md);
}

.footer-social a {
    color: var(--gray-400);
    font-size: 1.25rem;
    transition: color var(--transition-fast);
}

.footer-social a:hover {
    color: var(--white);
}

/* ============================================
   Buttons
   ============================================ */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: 0.75rem 1.5rem;
    font-size: 0.95rem;
    font-weight: 600;
    border-radius: var(--radius-lg);
    border: none;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
    font-family: var(--font-primary);
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: var(--white);
    box-shadow: var(--shadow-blue);
}

.btn-primary:hover {
    background: linear-gradient(135deg, var(--primary-dark), var(--primary-800));
    color: var(--white);
    box-shadow: var(--shadow-blue-lg);
    transform: translateY(-1px);
}

.btn-secondary {
    background: var(--primary-50);
    color: var(--primary);
}

.btn-secondary:hover {
    background: var(--primary-100);
    color: var(--primary-dark);
}

.btn-outline {
    background: transparent;
    border: 1.5px solid var(--gray-200);
    color: var(--gray-700);
}

.btn-outline:hover {
    border-color: var(--primary);
    color: var(--primary);
    background: var(--primary-50);
}

/* ============================================
   Utility Classes
   ============================================ */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mt-4 { margin-top: var(--spacing-xl); }

.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }
.mb-4 { margin-bottom: var(--spacing-xl); }

.hidden { display: none !important; }
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
}