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

:root {
    --primary-color: #4a90e2;
    --secondary-color: #2c3e50;
    --surface-color: rgba(13, 17, 27, 0.65);
    --surface-border: rgba(255, 255, 255, 0.12);
    --text-primary: #f4f7ff;
    --text-secondary: #b8c2d9;
    --shadow-soft: 0 18px 48px rgba(2, 8, 20, 0.35);
    --radius-md: 14px;
    --radius-lg: 20px;
    --radius-pill: 999px;
    --space-1: clamp(0.5rem, 0.45rem + 0.2vw, 0.75rem);
    --space-2: clamp(0.75rem, 0.7rem + 0.35vw, 1.1rem);
    --space-3: clamp(1rem, 0.9rem + 0.65vw, 1.5rem);
    --space-4: clamp(1.5rem, 1.3rem + 0.95vw, 2.25rem);
    --space-5: clamp(2rem, 1.6rem + 1.5vw, 3.5rem);
    --container-width: min(1120px, 92vw);
    --motion-spring: 280ms cubic-bezier(0.22, 1, 0.36, 1);
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    background: radial-gradient(circle at 15% -10%, color-mix(in srgb, var(--primary-color) 35%, transparent), transparent 40%),
        radial-gradient(circle at 90% 5%, color-mix(in srgb, var(--secondary-color) 65%, #150d2f), transparent 52%),
        linear-gradient(145deg, #090c16, #0a1221 45%, #0f1324);
    line-height: 1.65;
    overflow-x: hidden;
}

body::before,
body::after {
    content: "";
    position: fixed;
    inset: -25%;
    pointer-events: none;
    z-index: -1;
}

body::before {
    background: conic-gradient(from 200deg, color-mix(in srgb, var(--primary-color) 22%, transparent), transparent 28%, color-mix(in srgb, var(--secondary-color) 25%, transparent), transparent 62%);
    filter: blur(64px);
    opacity: 0.55;
    animation: gradientDrift 18s ease-in-out infinite alternate;
}

body::after {
    background: radial-gradient(circle at var(--pointer-x, 50%) var(--pointer-y, 30%), color-mix(in srgb, var(--primary-color) 35%, transparent), transparent 38%);
    opacity: 0.35;
    transition: opacity 200ms ease;
}

@keyframes gradientDrift {
    from { transform: translate3d(-2%, -1%, 0) scale(1); }
    to { transform: translate3d(2%, 1%, 0) scale(1.06); }
}

.container,
.main-content,
.app-detail {
    width: var(--container-width);
    margin: 0 auto;
}

.container {
    padding-inline: var(--space-3);
}

p, li {
    color: var(--text-secondary);
}

h1, h2, h3 {
    letter-spacing: -0.02em;
    line-height: 1.2;
    margin-top: 0;
}

h1 { font-size: clamp(2rem, 1.5rem + 2.2vw, 3.75rem); }
h2 { font-size: clamp(1.5rem, 1.1rem + 1.2vw, 2.25rem); }
h3 { font-size: clamp(1.1rem, 0.95rem + 0.8vw, 1.5rem); }

a {
    color: color-mix(in srgb, var(--primary-color) 78%, white);
}

/* Navbar */
.navbar {
    position: sticky;
    top: var(--space-2);
    z-index: 50;
    width: min(1160px, 94vw);
    margin: var(--space-3) auto 0;
    padding: 0.75rem 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: color-mix(in srgb, var(--surface-color) 88%, rgba(0, 0, 0, 0.22));
    border: 1px solid var(--surface-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-soft);
    backdrop-filter: blur(14px);
}

.navbar .logo a {
    display: inline-flex;
    align-items: center;
    color: var(--text-primary);
    font-weight: 700;
    text-decoration: none;
}

.logo-img {
    height: clamp(58px, 6.8vw, 82px);
    width: auto;
}

.mobile-nav-toggle {
    display: none;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 12px;
    padding: 0.45rem 0.6rem;
    background: rgba(255, 255, 255, 0.05);
    color: #fff;
    font-size: 1rem;
    cursor: pointer;
}

.nav-links {
    list-style: none;
    display: flex;
    align-items: center;
    gap: 0.4rem;
    margin: 0;
    padding: 0;
}

.nav-links > li > a {
    position: relative;
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 600;
    letter-spacing: 0.01em;
    padding: 0.65rem 0.85rem;
    border-radius: 10px;
    transition: color var(--motion-spring), background-color var(--motion-spring);
}

.nav-links > li > a::after {
    content: "";
    position: absolute;
    left: 0.8rem;
    right: 0.8rem;
    bottom: 0.35rem;
    height: 2px;
    border-radius: var(--radius-pill);
    background: linear-gradient(90deg, color-mix(in srgb, var(--primary-color) 65%, white), color-mix(in srgb, var(--secondary-color) 65%, white));
    transform: scaleX(0);
    transform-origin: center;
    transition: transform var(--motion-spring);
}

.nav-links > li > a:hover,
.nav-links > li > a.active-link {
    color: #fff;
    background-color: rgba(255, 255, 255, 0.06);
}

.nav-links > li > a:hover::after,
.nav-links > li > a.active-link::after {
    transform: scaleX(1);
}

.dropdown {
    position: relative;
}

.dropdown-content {
    position: absolute;
    top: calc(100% + 0.45rem);
    left: 0;
    display: grid;
    gap: 0.2rem;
    list-style: none;
    margin: 0;
    padding: 0.4rem;
    min-width: 180px;
    background: rgba(6, 10, 18, 0.92);
    border: 1px solid rgba(255, 255, 255, 0.16);
    border-radius: var(--radius-md);
    box-shadow: 0 12px 30px rgba(0, 0, 0, 0.35);
    opacity: 0;
    visibility: hidden;
    transform: translateY(8px);
    transition: opacity var(--motion-spring), transform var(--motion-spring), visibility var(--motion-spring);
}

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

.dropdown-content li a {
    display: block;
    padding: 0.58rem 0.75rem;
    color: #edf2ff;
    text-decoration: none;
    border-radius: 9px;
    transition: background-color var(--motion-spring), transform var(--motion-spring);
}

.dropdown-content li a:hover {
    background-color: rgba(255, 255, 255, 0.1);
    transform: translateX(2px);
}

/* Hero Section */
.hero {
    min-height: min(84vh, 900px);
    display: grid;
    place-items: center;
    padding-block: var(--space-5);
}

.hero-content {
    text-align: center;
    background: linear-gradient(150deg, rgba(255, 255, 255, 0.08), rgba(255, 255, 255, 0.02));
    border: 1px solid rgba(255, 255, 255, 0.15);
    box-shadow: var(--shadow-soft);
    border-radius: calc(var(--radius-lg) + 6px);
    padding: clamp(2rem, 2.8vw, 3.75rem);
    position: relative;
    overflow: hidden;
    transform: translateZ(0);
}

.hero-content::before {
    content: "";
    position: absolute;
    inset: -45% auto auto -25%;
    width: 260px;
    height: 260px;
    border-radius: 50%;
    background: color-mix(in srgb, var(--primary-color) 35%, transparent);
    filter: blur(45px);
    opacity: 0.75;
}

.hero p {
    max-width: 56ch;
    margin: 0.75rem auto var(--space-4);
    font-size: clamp(1rem, 0.92rem + 0.7vw, 1.25rem);
}

.cta-button,
.support-button,
.secondary-button,
#go-home-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.35rem;
    padding: 0.78rem 1.4rem;
    border-radius: var(--radius-pill);
    border: 1px solid transparent;
    text-decoration: none;
    font-weight: 700;
    font-size: 0.98rem;
    letter-spacing: 0.01em;
    cursor: pointer;
    transition: transform var(--motion-spring), box-shadow var(--motion-spring), background-color var(--motion-spring), border-color var(--motion-spring);
    will-change: transform;
}

.cta-button {
    color: #fff;
    background: linear-gradient(115deg, color-mix(in srgb, var(--primary-color) 84%, #fff 16%), color-mix(in srgb, var(--secondary-color) 70%, #6f6bff));
    box-shadow: 0 12px 28px color-mix(in srgb, var(--primary-color) 40%, transparent);
}

.support-button,
.secondary-button {
    color: #f4f7ff;
    background: rgba(255, 255, 255, 0.06);
    border-color: rgba(255, 255, 255, 0.2);
}

.hero-content .cta-button,
.hero-content .support-button {
    margin: 0.25rem;
}

.cta-button:hover,
.support-button:hover,
.secondary-button:hover,
#go-home-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 16px 30px rgba(0, 0, 0, 0.3);
}

/* Content sections */
.story-section,
.invite-section,
.download-section,
.main-content,
.app-detail {
    margin-block: var(--space-4);
}

.story-collapse,
.app-detail,
.main-content,
.header {
    background: linear-gradient(155deg, rgba(255, 255, 255, 0.08), rgba(255, 255, 255, 0.03));
    border: 1px solid rgba(255, 255, 255, 0.14);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-soft);
}

.story-collapse {
    padding: var(--space-3);
}

.story-collapse summary {
    font-weight: 600;
    font-size: clamp(1.05rem, 0.96rem + 0.45vw, 1.35rem);
    cursor: pointer;
    color: #fff;
}

.story-content {
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    transition: max-height 0.4s ease, opacity 0.4s ease;
}

.story-collapse[open] .story-content {
    max-height: 280px;
    opacity: 1;
}

.app-detail,
.main-content {
    padding: clamp(1.4rem, 2vw, 2.5rem);
}

.app-detail {
    text-align: left;
}

.app-detail h2 {
    margin-bottom: 0.7rem;
}

.app-logo {
    display: block;
    max-width: min(210px, 44vw);
    margin: 0 auto var(--space-3);
    border-radius: 24%;
    border: 1px solid rgba(255, 255, 255, 0.2);
    box-shadow: 0 18px 35px rgba(0, 0, 0, 0.35);
}

.app-detail .section-title {
    margin-top: var(--space-4);
    margin-bottom: var(--space-2);
    color: color-mix(in srgb, var(--primary-color) 66%, #fff);
}

.app-detail ul,
.main-content ul {
    padding-left: 1.1rem;
}

.policy-section,
.terms-section {
    margin-bottom: var(--space-4);
    padding-bottom: var(--space-2);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.policy-section:last-child,
.terms-section:last-child {
    border-bottom: 0;
    margin-bottom: 0;
    padding-bottom: 0;
}

.header {
    width: var(--container-width);
    margin: var(--space-4) auto var(--space-3);
    padding: var(--space-3);
    text-align: center;
}

.invite-section {
    padding: var(--space-3);
    border-radius: var(--radius-md);
    border: 1px solid rgba(255, 255, 255, 0.16);
    background: rgba(255, 255, 255, 0.05);
}

.invite-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.65rem;
    margin-top: 1rem;
}

.invite-code {
    display: inline-flex;
    align-items: center;
    padding: 0.45rem 0.8rem;
    border-radius: var(--radius-pill);
    background: rgba(0, 0, 0, 0.3);
    border: 1px solid rgba(255, 255, 255, 0.16);
    color: #fff;
    font-weight: 600;
}

.copy-status {
    min-height: 1.2rem;
    margin: 0.75rem 0 0;
    color: color-mix(in srgb, var(--primary-color) 65%, #fff);
}

.download-section {
    display: flex;
    justify-content: center;
}

.disabled-link {
    color: #c8d0e8;
    pointer-events: none;
}

/* Footer */
.footer {
    text-align: center;
    padding: 1.1rem;
    margin-top: auto;
    color: #dce5ff;
    background: rgba(6, 10, 18, 0.75);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(8px);
}

/* Reusable motion */
.reveal {
    opacity: 0;
    transform: translate3d(0, 20px, 0) scale(0.98);
    transition: opacity 620ms ease, transform 620ms cubic-bezier(0.22, 1, 0.36, 1);
}

.reveal.is-visible {
    opacity: 1;
    transform: translate3d(0, 0, 0) scale(1);
}

/* Accent treatments per page/section */
.app-detail,
.main-content,
.hero-content,
.header,
.story-collapse {
    position: relative;
}

.app-detail::after,
.main-content::after,
.hero-content::after,
.header::after,
.story-collapse::after {
    content: "";
    position: absolute;
    inset: auto -8% -35% auto;
    width: 220px;
    height: 220px;
    border-radius: 50%;
    background: color-mix(in srgb, var(--primary-color) 40%, transparent);
    filter: blur(55px);
    opacity: 0.35;
    pointer-events: none;
}

/* Responsive */
@media (max-width: 880px) {
    .navbar {
        top: 0.6rem;
        padding: 0.7rem;
        border-radius: 16px;
    }

    .mobile-nav-toggle {
        display: inline-flex;
        align-items: center;
        justify-content: center;
    }

    .nav-links {
        position: absolute;
        right: 0.7rem;
        top: calc(100% + 0.45rem);
        width: min(320px, calc(100vw - 1.6rem));
        display: grid;
        gap: 0.2rem;
        padding: 0.5rem;
        border-radius: var(--radius-md);
        background: rgba(7, 12, 20, 0.95);
        border: 1px solid rgba(255, 255, 255, 0.17);
        box-shadow: 0 20px 36px rgba(0, 0, 0, 0.38);
        opacity: 0;
        visibility: hidden;
        transform: translateY(-8px) scale(0.98);
        transform-origin: top right;
        transition: opacity var(--motion-spring), transform var(--motion-spring), visibility var(--motion-spring);
    }

    .nav-links.open {
        opacity: 1;
        visibility: visible;
        transform: translateY(0) scale(1);
    }

    .dropdown-content {
        position: static;
        display: none;
        opacity: 1;
        visibility: visible;
        transform: none;
        margin: 0.25rem 0 0.15rem;
        box-shadow: none;
        background: rgba(255, 255, 255, 0.04);
    }

    .dropdown.open .dropdown-content {
        display: block;
    }

    .hero {
        min-height: 74vh;
    }
}

@media (max-width: 640px) {
    .container,
    .main-content,
    .app-detail,
    .header {
        width: min(1120px, 94vw);
    }

    .app-detail,
    .main-content,
    .header,
    .hero-content {
        padding: 1.15rem;
        border-radius: 16px;
    }

    .invite-actions {
        flex-direction: column;
        align-items: stretch;
    }

    .cta-button,
    .secondary-button,
    .support-button {
        width: 100%;
    }
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 1ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 1ms !important;
        scroll-behavior: auto !important;
    }
}