:root {
    --primary: #4f46e5;
    --primary-dark: #4338ca;
    --bg-light: #f8fafc;
    --text-dark: #1e293b;
    --text-muted: #64748b;
    --white: #ffffff;
    --slate-800: #1e293b;
    --slate-900: #0f172a;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    color: var(--text-dark);
    background-color: var(--white);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Navbar */
.navbar {
    padding: 1.5rem 0;
    position: sticky;
    top: 0;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    z-index: 100;
    border-bottom: 1px solid #e2e8f0;
}

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

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 800;
    font-size: 1.25rem;
    color: var(--primary);
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 2rem;
    align-items: center;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-dark);
    font-weight: 500;
    transition: color 0.3s;
}

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

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border-radius: 0.75rem;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s;
}

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

.btn-primary:hover {
    background-color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(79, 70, 229, 0.3);
}

.btn-secondary {
    background-color: #f1f5f9;
    color: var(--text-dark) !important;
}

.btn-secondary:hover {
    background-color: #e2e8f0;
}

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

.btn-white:hover {
    background-color: #f8fafc;
}

/* Hero Section */
.hero {
    padding: 4rem 0;
    background: linear-gradient(180deg, var(--white) 0%, var(--bg-light) 100%);
    overflow: hidden;
}

.hero-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 4rem;
}

.hero-text {
    flex: 1;
    max-width: 600px;
}

.hero-text h1 {
    font-size: 3.5rem;
    line-height: 1.1;
    margin-bottom: 1.5rem;
    letter-spacing: -0.02em;
}

.hero-text p {
    font-size: 1.25rem;
    color: var(--text-muted);
    margin-bottom: 2rem;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
}

.badges {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.badge {
    background-color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 2rem;
    font-size: 0.875rem;
    font-weight: 500;
    border: 1px solid #e2e8f0;
    color: var(--text-muted);
}

/* Phone Mockup Styling */
.phone-mockup {
    flex: 0 0 320px;
    height: 650px;
    background: #1e293b;
    border-radius: 40px;
    padding: 12px;
    position: relative;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    border: 4px solid #334155;
    transform: rotate(-5deg);
    transition: transform 0.5s;
}

.phone-mockup:hover {
    transform: rotate(0deg) scale(1.02);
}

.dark-mode-phone {
    transform: rotate(5deg);
}

.notch {
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 120px;
    height: 25px;
    background: #1e293b;
    border-bottom-left-radius: 12px;
    border-bottom-right-radius: 12px;
    z-index: 20;
}

.screen {
    width: 100%;
    height: 100%;
    background: white;
    border-radius: 28px;
    overflow: hidden;
    position: relative;
    display: flex;
    flex-direction: column;
}

/* App UI Simulation inside the phone */
.app-ui {
    font-family: sans-serif;
    display: flex;
    flex-direction: column;
}

.app-ui.dark {
    background-color: var(--slate-900);
    color: #f1f5f9;
}

.app-header {
    padding: 30px 16px 16px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid #e2e8f0;
}

.app-ui.dark .app-header {
    border-color: #334155;
}

.app-logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: bold;
    color: #1e293b;
}

.app-tabs {
    display: flex;
    border-bottom: 1px solid #e2e8f0;
}

.app-ui.dark .app-tabs {
    border-color: #334155;
}

.tab {
    flex: 1;
    text-align: center;
    padding: 12px;
    font-size: 12px;
    font-weight: bold;
    color: #94a3b8;
}

.tab.active {
    color: var(--primary);
    border-bottom: 2px solid var(--primary);
}

.app-ui.dark .tab.active {
    color: #818cf8;
    border-color: #818cf8;
}

.app-content {
    flex: 1;
    padding: 16px;
    display: flex;
    flex-direction: column;
}

.section-title {
    font-size: 12px;
    color: #64748b;
    margin-bottom: 12px;
    text-transform: uppercase;
}

.chart-area {
    background: white;
    border: 1px solid #e2e8f0;
    border-radius: 12px;
    height: 200px;
    margin-bottom: 16px;
    position: relative;
    padding: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.chart-svg {
    width: 100%;
    height: 100%;
}

.tooltip-mock {
    position: absolute;
    top: 20%;
    left: 40%;
    background: white;
    padding: 8px;
    border-radius: 8px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    font-size: 12px;
    display: flex;
    flex-direction: column;
    border: 1px solid #e2e8f0;
}

.action-buttons {
    display: flex;
    gap: 12px;
    height: 80px;
}

.btn-square {
    flex: 1;
    border: 1px solid #e2e8f0;
    border-radius: 12px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 4px;
    color: #475569;
    font-size: 10px;
    font-weight: bold;
}

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

.app-footer {
    padding: 16px;
    text-align: center;
    font-size: 10px;
    color: #94a3b8;
    background: #f8fafc;
    border-top: 1px solid #e2e8f0;
}

.app-ui.dark .app-footer {
    background: #0f172a;
    border-color: #334155;
    color: #64748b;
}

/* List Styles for Dark Mode Mockup */
.list-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: 12px;
}

.list-header .count {
    font-size: 12px;
    color: #64748b;
}

.history-item {
    background: #1e293b;
    border: 1px solid #334155;
    padding: 12px;
    border-radius: 8px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 8px;
}

.history-item .weight {
    font-size: 16px;
    font-weight: bold;
    color: white;
}

.history-item .weight span {
    font-size: 12px;
    font-weight: normal;
    color: #94a3b8;
}

.history-item .meta {
    font-size: 12px;
    color: #64748b;
}

.history-item .week {
    color: #818cf8;
}

.history-item .delete-icon {
    color: #64748b;
}

/* Features Section */
.features {
    padding: 6rem 0;
}

.section-heading {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 4rem;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.feature-card {
    padding: 2rem;
    border-radius: 1rem;
    background: var(--bg-light);
    transition: transform 0.3s;
}

.feature-card:hover {
    transform: translateY(-5px);
}

.icon-box {
    width: 48px;
    height: 48px;
    background: var(--white);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary);
    margin-bottom: 1.5rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
}

.feature-card h3 {
    margin-bottom: 1rem;
    font-size: 1.25rem;
}

.feature-card p {
    color: var(--text-muted);
}

/* Preview Section */
.preview {
    padding: 6rem 0;
    background: var(--slate-900);
    color: white;
}

.preview-content {
    display: flex;
    align-items: center;
    gap: 4rem;
    flex-direction: row-reverse;
}

.preview-text {
    flex: 1;
}

.preview-text h2 {
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
}

.preview-text p {
    color: #94a3b8;
    font-size: 1.25rem;
}

/* CTA */
.cta {
    padding: 6rem 0;
    text-align: center;
    background: var(--primary);
    color: white;
}

.cta h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.cta p {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

.small-text {
    font-size: 0.875rem;
    margin-top: 1rem;
    opacity: 0.7;
}

/* Footer */
footer {
    padding: 2rem 0;
    background: var(--slate-900);
    color: #64748b;
    border-top: 1px solid #334155;
    text-align: center;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
    
    .hero-content, .preview-content {
        flex-direction: column;
        text-align: center;
        gap: 3rem;
    }

    .hero-buttons {
        justify-content: center;
    }

    .badges {
        justify-content: center;
    }
    
    .hero-text h1 {
        font-size: 2.5rem;
    }
    
    .phone-mockup {
        margin: 0 auto;
    }
}