/* ===== Table to Excel - Product Website Design System ===== */

/* CSS Variables - Design Tokens */
:root {
    /* Colors */
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #3b82f6;
    --secondary: #10b981;
    --accent: #8b5cf6;
    --warning: #f59e0b;

    /* Neutrals */
    --dark-900: #0f172a;
    --dark-800: #1e293b;
    --dark-700: #334155;
    --dark-600: #475569;
    --light-100: #f8fafc;
    --light-200: #e2e8f0;
    --light-300: #cbd5e1;

    /* Gradients */
    --gradient-hero: linear-gradient(135deg, #0f172a 0%, #1e3a5f 50%, #0f172a 100%);
    --gradient-primary: linear-gradient(135deg, #2563eb 0%, #8b5cf6 100%);
    --gradient-donation: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);

    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', 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: 0.5rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    --shadow-glow: 0 0 40px rgba(37, 99, 235, 0.3);

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

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-sans);
    background: var(--dark-900);
    color: var(--light-100);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

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

a:hover {
    color: var(--accent);
}

/* Typography */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-weight: 700;
    line-height: 1.2;
    color: var(--light-100);
}

h1 {
    font-size: clamp(2.5rem, 5vw, 4rem);
}

h2 {
    font-size: clamp(2rem, 4vw, 3rem);
}

h3 {
    font-size: clamp(1.5rem, 3vw, 2rem);
}

h4 {
    font-size: 1.25rem;
}

h5 {
    font-size: 1rem;
}

p {
    color: var(--light-300);
    margin-bottom: var(--spacing-md);
}

.text-gradient {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Container */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.section {
    padding: var(--spacing-3xl) 0;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--radius-lg);
    border: none;
    cursor: pointer;
    transition: all var(--transition-base);
    text-decoration: none;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl), 0 0 60px rgba(37, 99, 235, 0.4);
    color: white;
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.1);
    color: var(--light-100);
    border: 1px solid rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.15);
    border-color: rgba(255, 255, 255, 0.3);
    color: white;
}

.btn-donation {
    background: linear-gradient(135deg, #fbbf24 0%, #f59e0b 100%);
    color: var(--dark-900);
}

.btn-donation:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(251, 191, 36, 0.3);
    color: var(--dark-900);
}

/* Cards */
.card {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    backdrop-filter: blur(10px);
    transition: all var(--transition-base);
}

.card:hover {
    background: rgba(255, 255, 255, 0.05);
    border-color: rgba(255, 255, 255, 0.12);
    transform: translateY(-4px);
}

.card-icon {
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.75rem;
    background: var(--gradient-primary);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-lg);
}

/* Header / Navigation */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: var(--spacing-md) 0;
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

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

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--light-100);
}

.logo-img {
    width: 36px;
    height: 36px;
    border-radius: var(--radius-sm);
}

.logo-text {
    display: flex;
    flex-direction: column;
    line-height: 1.2;
}

.logo-text span {
    font-size: 1.1rem;
    font-weight: 700;
}

.logo-text small {
    font-size: 0.7rem;
    font-weight: 500;
    color: var(--light-300);
    opacity: 0.8;
}

.logo-icon {
    font-size: 1.5rem;
}

.nav {
    display: flex;
    align-items: center;
    gap: var(--spacing-xl);
}

.nav a {
    color: var(--light-300);
    font-weight: 500;
    transition: color var(--transition-fast);
}

.nav a:hover {
    color: var(--light-100);
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: var(--gradient-hero);
    position: relative;
    overflow: hidden;
    padding-top: 80px;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 30% 50%, rgba(37, 99, 235, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 70% 80%, rgba(139, 92, 246, 0.1) 0%, transparent 40%);
    pointer-events: none;
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 900px;
    margin: 0 auto;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    background: rgba(37, 99, 235, 0.15);
    border: 1px solid rgba(37, 99, 235, 0.3);
    border-radius: var(--radius-full);
    font-size: 0.875rem;
    color: var(--primary-light);
    margin-bottom: var(--spacing-xl);
}

.hero h1 {
    margin-bottom: var(--spacing-lg);
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--light-300);
    max-width: 600px;
    margin: 0 auto var(--spacing-2xl);
}

.hero-buttons {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: var(--spacing-3xl);
    margin-top: var(--spacing-3xl);
}

.stat {
    text-align: center;
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--light-100);
}

.stat-label {
    font-size: 0.875rem;
    color: var(--light-300);
}

/* Features Section */
.features {
    background: var(--dark-800);
}

.section-header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto var(--spacing-3xl);
}

.section-header h2 {
    margin-bottom: var(--spacing-md);
}

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

/* How It Works Section */
.how-it-works {
    background: var(--dark-900);
}

.steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-xl);
    counter-reset: step;
}

.step {
    position: relative;
    padding: var(--spacing-xl);
    background: rgba(255, 255, 255, 0.02);
    border-radius: var(--radius-xl);
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.step::before {
    counter-increment: step;
    content: counter(step);
    display: flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    background: var(--gradient-primary);
    border-radius: var(--radius-full);
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: var(--spacing-lg);
}

.step h3 {
    margin-bottom: var(--spacing-sm);
}

/* Donation Banner */
.donation-banner {
    background: linear-gradient(135deg, rgba(251, 191, 36, 0.1) 0%, rgba(245, 158, 11, 0.1) 100%);
    border: 1px solid rgba(251, 191, 36, 0.2);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl) var(--spacing-2xl);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-xl);
    flex-wrap: wrap;
}

.donation-content {
    flex: 1;
    min-width: 280px;
}

.donation-content h3 {
    color: #fbbf24;
    margin-bottom: var(--spacing-sm);
}

.donation-content p {
    color: var(--light-200);
    margin-bottom: 0;
}

/* FAQ Section */
.faq {
    background: var(--dark-800);
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.faq-question {
    width: 100%;
    padding: var(--spacing-lg) 0;
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: none;
    border: none;
    color: var(--light-100);
    font-size: 1.125rem;
    font-weight: 600;
    cursor: pointer;
    text-align: left;
}

.faq-question::after {
    content: '+';
    font-size: 1.5rem;
    color: var(--primary);
    transition: transform var(--transition-base);
}

.faq-item.active .faq-question::after {
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-base);
}

.faq-item.active .faq-answer {
    max-height: 500px;
}

.faq-answer p {
    padding-bottom: var(--spacing-lg);
}

/* Footer */
.footer {
    background: var(--dark-900);
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    padding: var(--spacing-3xl) 0 var(--spacing-xl);
}

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

.footer-brand p {
    margin-top: var(--spacing-md);
    max-width: 300px;
}

.footer-links h4 {
    margin-bottom: var(--spacing-lg);
    color: var(--light-100);
}

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

.footer-links li {
    margin-bottom: var(--spacing-sm);
}

.footer-links a {
    color: var(--light-300);
    font-size: 0.9rem;
}

.footer-links a:hover {
    color: var(--light-100);
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: var(--spacing-xl);
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    font-size: 0.875rem;
    color: var(--light-300);
}

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

.footer-support a {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    background: rgba(251, 191, 36, 0.1);
    border: 1px solid rgba(251, 191, 36, 0.2);
    border-radius: var(--radius-md);
    color: #fbbf24;
    font-size: 0.875rem;
    transition: all var(--transition-fast);
}

.footer-support a:hover {
    background: rgba(251, 191, 36, 0.2);
    color: #fbbf24;
}

/* Responsive */
@media (max-width: 768px) {
    .nav {
        display: none;
    }

    .hero-stats {
        gap: var(--spacing-xl);
    }

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

    .footer-bottom {
        flex-direction: column;
        gap: var(--spacing-md);
        text-align: center;
    }

    .donation-banner {
        text-align: center;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .footer-grid {
        grid-template-columns: 1fr;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
}