/* ================================
   AI Personality Designer — Landing
   Minimalist Black & White
   ================================ */

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

:root {
    --black: #111111;
    --dark: #1a1a1a;
    --gray-900: #222222;
    --gray-700: #555555;
    --gray-500: #888888;
    --gray-300: #cccccc;
    --gray-100: #f5f5f5;
    --white: #ffffff;
    --accent: #111111;
    --font: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --max-width: 960px;
    --transition: 0.3s ease;
}

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

body {
    font-family: var(--font);
    background: var(--white);
    color: var(--black);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

h1,
h2,
h3,
h4 {
    font-weight: 500;
    line-height: 1.3;
    letter-spacing: -0.02em;
}

a {
    color: inherit;
    text-decoration: none;
}

ul {
    list-style: none;
}

/* --- Nav --- */
nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--gray-100);
    transition: var(--transition);
}

nav.scrolled {
    box-shadow: 0 1px 8px rgba(0, 0, 0, 0.06);
}

.nav-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 64px;
}

.logo {
    font-size: 1.125rem;
    font-weight: 600;
    letter-spacing: -0.03em;
}

.nav-links {
    display: flex;
    gap: 32px;
}

.nav-links a {
    font-size: 0.875rem;
    color: var(--gray-700);
    transition: color var(--transition);
}

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

/* --- Buttons --- */
.btn {
    display: inline-block;
    padding: 12px 28px;
    font-size: 0.9375rem;
    font-weight: 500;
    border-radius: 6px;
    transition: all var(--transition);
    cursor: pointer;
    border: none;
    font-family: var(--font);
}

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

.btn-primary:hover {
    background: var(--gray-900);
    transform: translateY(-1px);
}

.btn-secondary {
    background: transparent;
    color: var(--black);
    border: 1px solid var(--gray-300);
}

.btn-secondary:hover {
    border-color: var(--black);
}

.btn-large {
    padding: 16px 40px;
    font-size: 1rem;
}

/* --- Hero --- */
.hero {
    padding: 160px 0 100px;
}

.hero h1 {
    font-size: clamp(2.5rem, 5vw, 3.5rem);
    font-weight: 600;
    margin-bottom: 16px;
    letter-spacing: -0.03em;
}

.hero-sub {
    font-size: 1.25rem;
    color: var(--gray-700);
    margin-bottom: 24px;
}

.hero-sub em {
    font-style: italic;
    color: var(--black);
}

.hero-desc {
    font-size: 1.0625rem;
    color: var(--gray-700);
    max-width: 560px;
    margin-bottom: 40px;
    line-height: 1.8;
}

.hero-cta {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

/* --- Quote --- */
.quote-section {
    padding: 80px 0;
    border-top: 1px solid var(--gray-100);
    border-bottom: 1px solid var(--gray-100);
}

.quote-section blockquote {
    font-size: 1.375rem;
    font-weight: 300;
    line-height: 1.8;
    color: var(--gray-700);
    max-width: 640px;
    font-style: italic;
}

/* --- Showcase --- */
.showcase {
    padding: 100px 0;
}

.showcase h2 {
    font-size: 1.75rem;
    margin-bottom: 48px;
}

.showcase-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.showcase-item {
    overflow: hidden;
    border-radius: 8px;
}

.showcase-item img {
    width: 100%;
    height: 240px;
    object-fit: cover;
    display: block;
    border-radius: 8px;
    transition: transform 0.4s ease;
}

.showcase-item:hover img {
    transform: scale(1.03);
}

.showcase-item p {
    font-size: 0.875rem;
    color: var(--gray-500);
    margin-top: 12px;
    text-align: center;
}

/* --- Approach --- */
.approach {
    padding: 100px 0;
}

.approach h2 {
    font-size: 1.75rem;
    margin-bottom: 56px;
}

.approach-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 48px;
}

.approach-item h3 {
    font-size: 1.0625rem;
    font-weight: 600;
    margin-bottom: 12px;
}

.approach-item p {
    font-size: 0.9375rem;
    color: var(--gray-700);
    line-height: 1.8;
}

/* --- Services --- */
.services {
    padding: 100px 0;
    background: var(--gray-100);
}

.services h2 {
    font-size: 1.75rem;
    margin-bottom: 56px;
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    margin-bottom: 48px;
}

.service-card {
    background: var(--white);
    padding: 36px 32px;
    border-radius: 8px;
    border: 1px solid var(--gray-300);
    transition: all var(--transition);
}

.service-card:hover {
    border-color: var(--black);
}

.service-card.featured {
    border-color: var(--black);
    box-shadow: 0 2px 16px rgba(0, 0, 0, 0.08);
}

.service-tier {
    font-size: 0.8125rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--gray-500);
    display: block;
    margin-bottom: 16px;
}

.service-card.featured .service-tier {
    color: var(--black);
}

.service-desc {
    font-size: 0.9375rem;
    color: var(--gray-700);
    line-height: 1.8;
    margin-bottom: 24px;
}

.service-detail {
    font-size: 0.8125rem;
    color: var(--gray-500);
}

.services-cta {
    text-align: center;
}

/* --- Platforms --- */
.platforms {
    padding: 80px 0;
    text-align: center;
}

.platforms h2 {
    font-size: 1.25rem;
    font-weight: 500;
    margin-bottom: 32px;
    color: var(--gray-700);
}

.platform-list {
    display: flex;
    justify-content: center;
    gap: 32px;
    flex-wrap: wrap;
    margin-bottom: 16px;
}

.platform-list span {
    font-size: 1rem;
    font-weight: 500;
    color: var(--black);
    padding: 8px 0;
}

.platform-note {
    font-size: 0.875rem;
    color: var(--gray-500);
    margin-top: 8px;
}

/* --- Fit --- */
.fit {
    padding: 100px 0;
    border-top: 1px solid var(--gray-100);
}

.fit-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 48px;
}

.fit-card h3 {
    font-size: 1.0625rem;
    font-weight: 600;
    margin-bottom: 20px;
}

.fit-card ul {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.fit-card li {
    font-size: 0.9375rem;
    color: var(--gray-700);
    padding-left: 20px;
    position: relative;
}

.fit-card li::before {
    content: '—';
    position: absolute;
    left: 0;
    color: var(--gray-500);
}

/* --- Contact --- */
.contact {
    padding: 120px 0;
    text-align: center;
    background: var(--black);
    color: var(--white);
}

.contact h2 {
    font-size: 2rem;
    margin-bottom: 16px;
}

.contact p {
    color: var(--gray-500);
    font-size: 1.0625rem;
    margin-bottom: 40px;
}

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

.contact .btn-primary:hover {
    background: var(--gray-100);
    transform: translateY(-1px);
}

/* --- Footer --- */
footer {
    padding: 32px 0;
    text-align: center;
    border-top: 1px solid var(--gray-100);
}

footer p {
    font-size: 0.8125rem;
    color: var(--gray-500);
}

/* --- Animations --- */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* --- Responsive --- */
@media (max-width: 768px) {
    .hero {
        padding: 120px 0 80px;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .approach-grid,
    .services-grid,
    .showcase-grid {
        grid-template-columns: 1fr;
        gap: 32px;
    }

    .fit-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .nav-links {
        gap: 20px;
    }

    .nav-links a {
        font-size: 0.8125rem;
    }

    .platform-list {
        gap: 20px;
    }
}

@media (max-width: 480px) {
    .hero-cta {
        flex-direction: column;
    }

    .btn {
        text-align: center;
    }

    .nav-links {
        display: none;
    }
}