@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&display=swap');

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary: #3b82f6;
    --primary-dark: #2563eb;
    --primary-light: #60a5fa;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #64748b;
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --border: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 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);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-secondary);
    color: var(--text-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.landing-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
.landing-header {
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border);
    padding: 1.25rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(12px);
    background: rgba(255, 255, 255, 0.95);
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-weight: 700;
    font-size: 1.125rem;
    color: var(--text-primary);
}

.logo-img {
    height: 80px;
    width: auto;
    object-fit: contain;
    display: block;
}

.footer-logo-img {
    height: 32px;
    width: auto;
}

.cta-button {
    background: var(--primary);
    color: white;
    padding: 0.625rem 1.5rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9375rem;
    transition: all 0.2s;
    box-shadow: var(--shadow-sm);
}

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

/* Authentication UI */
.header-auth {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.sign-in-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border);
    padding: 0.625rem 1.25rem;
    border-radius: 8px;
    font-weight: 600;
    font-size: 0.9375rem;
    cursor: pointer;
    transition: all 0.2s;
    font-family: inherit;
}

.sign-in-btn:hover {
    background: var(--bg-tertiary);
    border-color: var(--primary);
    transform: translateY(-1px);
    box-shadow: var(--shadow-sm);
}

.sign-in-btn svg {
    color: var(--primary);
}

.user-profile {
    position: relative;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.5rem 1rem;
    border-radius: 50px;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    cursor: pointer;
    transition: all 0.2s;
}

.user-profile:hover {
    background: var(--bg-tertiary);
    border-color: var(--primary);
}

.user-avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    object-fit: cover;
    border: 2px solid var(--primary);
}

.user-name {
    font-weight: 600;
    font-size: 0.9375rem;
    color: var(--text-primary);
    max-width: 150px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.user-dropdown {
    position: absolute;
    top: calc(100% + 0.5rem);
    right: 0;
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: 12px;
    box-shadow: var(--shadow-lg);
    min-width: 200px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.2s;
    z-index: 1000;
}

.user-profile.active .user-dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown-item {
    display: block;
    width: 100%;
    padding: 0.75rem 1.25rem;
    text-align: left;
    background: none;
    border: none;
    color: var(--text-primary);
    font-weight: 500;
    font-size: 0.9375rem;
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
    font-family: inherit;
}

.dropdown-item:first-child {
    border-radius: 12px 12px 0 0;
}

.dropdown-item:last-child {
    border-radius: 0 0 12px 12px;
    border-top: 1px solid var(--border);
}

.dropdown-item:hover {
    background: var(--bg-secondary);
    color: var(--primary);
}


/* Hero Section */
.hero {
    padding: 5rem 2rem;
    background: linear-gradient(135deg, #f8fafc 0%, #e0f2fe 100%);
    border-bottom: 1px solid var(--border);
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: rgba(59, 130, 246, 0.1);
    color: var(--primary);
    padding: 0.5rem 1rem;
    border-radius: 50px;
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 1.5rem;
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--primary) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-description {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 2.5rem;
    line-height: 1.7;
}

.free-badge-float {
    display: inline-flex;
    align-items: center;
    gap: 0.625rem;
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
    color: white;
    padding: 0.625rem 1.25rem;
    border-radius: 50px;
    font-size: 0.875rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
    box-shadow: 0 4px 15px rgba(16, 185, 129, 0.4);
    animation: float 3s ease-in-out infinite;
    border: 1px solid rgba(255, 255, 255, 0.2);
    letter-spacing: 0.05em;
}

@keyframes float {
    0% {
        transform: translateY(0px);
    }

    50% {
        transform: translateY(-10px);
    }

    100% {
        transform: translateY(0px);
    }
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.primary-button {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: linear-gradient(135deg, var(--primary-light) 0%, var(--primary) 100%);
    color: white;
    padding: 1rem 2rem;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 700;
    font-size: 1.0625rem;
    transition: all 0.3s;
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}

.primary-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(59, 130, 246, 0.4);
}

.primary-button.large {
    padding: 1.25rem 2.5rem;
    font-size: 1.125rem;
}

/* Features Section */
.features {
    padding: 5rem 2rem;
    background: var(--bg-primary);
}

.features-grid {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: var(--bg-secondary);
    padding: 2rem;
    border-radius: 16px;
    border: 1px solid var(--border);
    transition: all 0.3s;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-light);
}

.feature-card.highlighted {
    border: 2px solid #10b981;
    background: rgba(16, 185, 129, 0.05);
    position: relative;
    overflow: hidden;
}

.feature-card.highlighted::before {
    content: 'BEST VALUE';
    position: absolute;
    top: 12px;
    right: -25px;
    background: #10b981;
    color: white;
    font-size: 0.625rem;
    font-weight: 800;
    padding: 2px 30px;
    transform: rotate(45deg);
}

.feature-icon.free-icon {
    background: linear-gradient(135deg, #34d399 0%, #10b981 100%);
}

.feature-icon {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--primary-light) 0%, var(--primary) 100%);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.25rem;
    color: white;
}

.feature-card h3 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.7;
    font-size: 0.9375rem;
}

/* Topics Section */
.topics {
    padding: 5rem 2rem;
    background: var(--bg-secondary);
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 3rem;
    color: var(--text-primary);
}

.topics-grid {
    max-width: 900px;
    margin: 0 auto;
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: center;
}

.topic-tag {
    background: var(--bg-primary);
    border: 2px solid var(--border);
    padding: 0.75rem 1.5rem;
    border-radius: 50px;
    font-weight: 600;
    color: var(--text-primary);
    transition: all 0.2s;
    font-size: 0.9375rem;
}

.topic-tag:hover {
    border-color: var(--primary);
    color: var(--primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* CTA Section */
.cta-section {
    padding: 5rem 2rem;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: white;
}

.cta-content {
    max-width: 700px;
    margin: 0 auto;
    text-align: center;
}

.cta-content h2 {
    font-size: 2.75rem;
    font-weight: 800;
    margin-bottom: 1rem;
}

.cta-content p {
    font-size: 1.25rem;
    margin-bottom: 2.5rem;
    opacity: 0.95;
}

.cta-section .primary-button {
    background: white;
    color: var(--primary);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.cta-section .primary-button:hover {
    background: var(--bg-secondary);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.3);
}

/* Footer */
.landing-footer {
    background: var(--bg-primary);
    border-top: 1px solid var(--border);
    padding: 3rem 2rem;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 2rem;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-weight: 700;
    font-size: 1.0625rem;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
}

.footer-description {
    color: var(--text-secondary);
    font-size: 0.9375rem;
    max-width: 400px;
}

.footer-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s;
}

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

/* Responsive */
@media (max-width: 768px) {
    .logo-img {
        height: 60px;
    }

    .footer-logo-img {
        height: 28px;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .hero-description {
        font-size: 1.0625rem;
    }

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

    .section-title {
        font-size: 2rem;
    }

    .cta-content h2 {
        font-size: 2rem;
    }

    .footer-content {
        flex-direction: column;
        text-align: center;
    }

    .footer-description {
        max-width: 100%;
    }
}

/* dark-mode-override landing */
:root {
    --primary: #60a5fa;
    --primary-dark: #3b82f6;
    --primary-light: #93c5fd;
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --bg-primary: #0f0f23;
    --bg-secondary: #12142a;
    --bg-tertiary: #1a1f3a;
    --border: rgba(96, 165, 250, 0.15);
}

body {
    background: var(--bg-primary);
    color: var(--text-primary);
}

.landing-header {
    background: rgba(20, 20, 35, 0.9);
    border-bottom: 1px solid var(--border);
}

.hero {
    background: linear-gradient(135deg, #0f0f23 0%, #1a1a2e 50%, #16213e 100%);
    border-bottom: 1px solid var(--border);
}

.features {
    background: var(--bg-primary);
}

.feature-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
}

.topics {
    background: var(--bg-secondary);
}

.section-title {
    color: var(--text-primary);
}

.topic-tag {
    background: var(--bg-primary);
    border-color: var(--border);
    color: var(--text-primary);
}

.cta-section .primary-button {
    background: white;
    color: var(--primary);
}

.landing-footer {
    background: var(--bg-primary);
    border-top: 1px solid var(--border);
}

.footer-link {
    color: var(--text-secondary);
}

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

.hero-description,
.feature-card p,
.footer-description {
    color: var(--text-secondary);
}

.logo,
.footer-logo,
.feature-card h3 {
    color: var(--text-primary);
}