:root {
    --bg-primary: #050505;
    --bg-secondary: #0a0a0f;
    --bg-hero: #ffffff;
    --text-primary: #ffffff;
    --text-secondary: #888899;
    --text-dark: #111111;
    --text-dark-secondary: #555555;
    --accent: #3b82f6;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Monaco, Consolas, "Liberation Mono", "DejaVu Sans Mono", monospace;
    background: var(--bg-primary);
    color: var(--text-primary);
    overflow-x: hidden;
    line-height: 1.6;
}

h1, h2, h3, h4 {
    font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Monaco, Consolas, "Liberation Mono", "DejaVu Sans Mono", monospace;
    font-weight: 700;
}

/* Navbar */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    padding: 1.5rem 3rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 1000;
    transition: background 0.3s ease, backdrop-filter 0.3s ease, color 0.3s ease;
    color: var(--text-dark);
}

.navbar.on-dark {
    color: var(--text-primary);
}

.navbar.scrolled {
    backdrop-filter: blur(12px);
}

.navbar.on-dark.scrolled {
    background: rgba(5, 5, 5, 0.8);
}

.navbar:not(.on-dark).scrolled {
    background: rgba(245, 245, 245, 0.8);
}

.nav-logo {
    position: relative;
    height: 60px;
}

.nav-logo img {
    height: 100%;
    width: auto;
    transition: opacity 0.3s ease;
}

.nav-logo .logo-black {
    opacity: 1;
}

.nav-logo .logo-white {
    position: absolute;
    top: 0;
    left: 0;
    opacity: 0;
}

.navbar.on-dark .nav-logo .logo-black {
    opacity: 0;
}

.navbar.on-dark .nav-logo .logo-white {
    opacity: 1;
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    color: var(--text-dark-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.2s ease;
    position: relative;
}

.navbar.on-dark .nav-links a {
    color: var(--text-secondary);
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 1px;
    background: var(--accent);
    transition: width 0.3s ease;
}

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

.navbar.on-dark .nav-links a:hover {
    color: var(--text-primary);
}

.nav-links a:hover::after {
    width: 100%;
}

/* Language Switch */
.lang-switch {
    margin-left: 1.5rem;
    background: none;
    border: 1px solid var(--text-dark-secondary);
    color: var(--text-dark);
    font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Monaco, Consolas, "Liberation Mono", "DejaVu Sans Mono", monospace;
    font-size: 0.85rem;
    font-weight: 700;
    padding: 0.35rem 0.7rem;
    border-radius: 4px;
    cursor: pointer;
    transition: border-color 0.2s ease, color 0.2s ease, background 0.2s ease;
}

.lang-switch:hover {
    border-color: var(--text-dark);
    background: rgba(0, 0, 0, 0.05);
}

.navbar.on-dark .lang-switch {
    border-color: var(--text-secondary);
    color: var(--text-primary);
}

.navbar.on-dark .lang-switch:hover {
    border-color: var(--text-primary);
    background: rgba(255, 255, 255, 0.1);
}

/* Hero */
.hero {
    position: relative;
    height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    overflow: hidden;
    background: var(--bg-hero);
}

.hero-dark-overlay {
    position: absolute;
    inset: 0;
    background: var(--bg-primary);
    pointer-events: none;
    z-index: 5;
    opacity: 0;
}

.hero-pretitle {
    font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Monaco, Consolas, "Liberation Mono", "DejaVu Sans Mono", monospace;
    font-size: 0.75rem;
    font-weight: 700;
    letter-spacing: 0.2em;
    color: var(--text-dark-secondary);
    margin-bottom: 2rem;
    opacity: 0;
    position: relative;
    z-index: 3;
}

.hero-product-wrapper {
    position: relative;
    width: 80%;
    max-width: 900px;
    display: flex;
    justify-content: center;
    align-items: center;
    perspective: 1200px;
    z-index: 3;
}

.hero-product-glow {
    position: absolute;
    width: 60%;
    height: 60%;
    background: radial-gradient(circle, rgba(59, 130, 246, 0.2) 0%, transparent 70%);
    border-radius: 50%;
    filter: blur(60px);
    opacity: 0.3;
    z-index: 0;
}

.hero-product {
    position: relative;
    z-index: 1;
    width: 100%;
    max-width: 800px;
    will-change: transform;
    filter: none;
    transform-origin: 50% 50%;
}

.hero-title {
    margin-top: 2rem;
    opacity: 0;
    position: relative;
    z-index: 3;
}

.hero-title h1 {
    font-size: clamp(2.5rem, 6vw, 5rem);
    font-weight: 700;
    letter-spacing: -0.03em;
    line-height: 1.1;
    color: var(--text-dark);
}

.hero-subtitle {
    font-size: 1.1rem;
    color: var(--text-dark-secondary);
    margin-top: 0.75rem;
    font-weight: 400;
}

.hero-cta {
    margin-top: 2rem;
}

/* Sections */
.section {
    padding: 8rem 2rem;
    position: relative;
    background: var(--bg-primary);
}

.section:nth-child(even) {
    background: var(--bg-secondary);
}

.container {
    max-width: 1000px;
    margin: 0 auto;
}

.container.centered {
    text-align: center;
}

.container.centered .section-desc {
    margin-left: auto;
    margin-right: auto;
}

/* Split layout for InspirationEngine */
.container.split {
    max-width: 1200px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.split-left {
    min-width: 0;
}

.split-right {
    position: relative;
    height: 500px;
    overflow: hidden;
    border-radius: 12px;
    background: #000;
}

.split-product {
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    height: 120%;
    width: auto;
    max-width: none;
}

.feature-grid.compact {
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    margin-top: 2rem;
}

.feature-grid.compact .feature-item h4 {
    font-size: 0.95rem;
}

.feature-grid.compact .feature-item p {
    font-size: 0.85rem;
}

.section-label {
    display: block;
    font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Monaco, Consolas, "Liberation Mono", "DejaVu Sans Mono", monospace;
    font-size: 0.75rem;
    letter-spacing: 0.15em;
    color: var(--accent);
    text-transform: uppercase;
    margin-bottom: 1.5rem;
}

.section h2 {
    font-size: clamp(2rem, 4vw, 3.5rem);
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.section-desc {
    font-size: 1.1rem;
    color: var(--text-secondary);
    max-width: 700px;
    margin-bottom: 3rem;
}

#prototype {
    background: #000000;
}

#engine {
    position: relative;
    z-index: 2;
    min-height: 100vh;
    display: flex;
    align-items: center;
}

.prototype-img {
    width: 100%;
    max-width: 900px;
    margin: 2rem auto 3rem;
    display: block;
    border-radius: 8px;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2.5rem;
    margin-top: 3rem;
}

.feature-item h4 {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.feature-item p {
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* Algo visual */
.algo-visual {
    display: flex;
    gap: 0.5rem;
    margin: 3rem 0;
    height: 80px;
    align-items: center;
    justify-content: center;
}

.algo-wave {
    width: 4px;
    height: 100%;
    background: linear-gradient(to top, var(--accent), transparent);
    border-radius: 2px;
    animation: wave 2s ease-in-out infinite;
}

.algo-wave:nth-child(1) { animation-delay: 0s; height: 100%; }
.algo-wave:nth-child(2) { animation-delay: 0.1s; height: 70%; }
.algo-wave:nth-child(3) { animation-delay: 0.2s; height: 85%; }
.algo-wave:nth-child(4) { animation-delay: 0.3s; height: 60%; }
.algo-wave:nth-child(5) { animation-delay: 0.4s; height: 90%; }
.algo-wave:nth-child(6) { animation-delay: 0.5s; height: 75%; }
.algo-wave:nth-child(7) { animation-delay: 0.6s; height: 50%; }
.algo-wave:nth-child(8) { animation-delay: 0.7s; height: 80%; }

@keyframes wave {
    0%, 100% { transform: scaleY(0.5); opacity: 0.5; }
    50% { transform: scaleY(1); opacity: 1; }
}

/* Release section */
.release-date {
    font-size: clamp(4rem, 10vw, 8rem);
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1;
    margin: 1rem 0 2rem;
    letter-spacing: -0.05em;
}

.cta-button {
    display: inline-block;
    padding: 1rem 2.5rem;
    background: var(--accent);
    color: #fff;
    text-decoration: none;
    font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Monaco, Consolas, "Liberation Mono", "DejaVu Sans Mono", monospace;
    font-weight: 700;
    border-radius: 4px;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.cta-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(59, 130, 246, 0.3);
}

/* About */
.social-links {
    display: flex;
    gap: 2rem;
    margin-top: 2rem;
    flex-wrap: wrap;
}

.social-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.2s ease;
}

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

/* Waitlist form */
.waitlist-form {
    margin-top: 2rem;
    max-width: 520px;
    margin-left: auto;
    margin-right: auto;
}

.waitlist-inputs {
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
    justify-content: center;
}

.waitlist-input {
    flex: 1 1 240px;
    padding: 1rem 1.25rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 4px;
    color: var(--text-primary);
    font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Monaco, Consolas, "Liberation Mono", "DejaVu Sans Mono", monospace;
    font-size: 0.9rem;
    transition: border-color 0.2s ease, background 0.2s ease;
    outline: none;
}

.waitlist-input::placeholder {
    color: var(--text-secondary);
}

.waitlist-input:focus {
    border-color: var(--accent);
    background: rgba(255, 255, 255, 0.08);
}

.waitlist-input:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.waitlist-msg {
    margin-top: 0.75rem;
    font-size: 0.85rem;
    min-height: 1.4em;
    color: var(--text-secondary);
}

.waitlist-msg.success {
    color: #22c55e;
}

.waitlist-msg.error {
    color: #ef4444;
}

.waitlist-msg.info {
    color: #e0b341;
}

/* Footer */
footer {
    padding: 3rem 2rem;
    text-align: center;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    color: var(--text-secondary);
    font-size: 0.85rem;
    background: var(--bg-primary);
}

/* Scroll reveal initial states */
.section h2,
.section-desc,
.feature-item,
.algo-visual,
.release-date,
.waitlist-form .cta-button,
.social-links {
    opacity: 0;
    transform: translateY(40px);
}

/* Mobile */
@media (max-width: 768px) {
    .navbar {
        padding: 1rem 1.5rem;
    }
    .nav-links {
        display: none;
    }
    .hero-product-wrapper {
        width: 95%;
    }
    .section {
        padding: 5rem 1.5rem;
    }
    .feature-grid {
        grid-template-columns: 1fr;
    }
    .algo-visual {
        height: 60px;
    }
    .container.split {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    .split-right {
        height: 280px;
        order: -1;
    }
    .feature-grid.compact {
        grid-template-columns: 1fr;
    }
}

/* WeChat QR modal */
.wechat-modal {
    position: fixed;
    inset: 0;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    animation: wechatFadeIn 0.2s ease-out;
}
.wechat-modal[hidden] {
    display: none;
}
.wechat-modal-backdrop {
    position: absolute;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(6px);
}
.wechat-modal-card {
    position: relative;
    background: #fff;
    color: #111;
    border-radius: 14px;
    padding: 2.25rem 2rem 1.75rem;
    box-shadow: 0 24px 80px rgba(0, 0, 0, 0.35);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.25rem;
    max-width: 92vw;
}
.wechat-modal-title {
    font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Monaco, Consolas, "Liberation Mono", "DejaVu Sans Mono", monospace;
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    margin: 0;
    color: #222;
}
.wechat-modal-qrs {
    display: flex;
    gap: 2rem;
    flex-wrap: wrap;
    justify-content: center;
}
.wechat-qr-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.6rem;
}
.wechat-qr-label {
    font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Monaco, Consolas, "Liberation Mono", "DejaVu Sans Mono", monospace;
    font-size: 0.85rem;
    color: #555;
    margin: 0;
    letter-spacing: 0.05em;
}
@media (max-width: 560px) {
    .wechat-modal-qrs { gap: 1rem; }
    .wechat-modal-qr { width: 160px; height: 160px; }
}
.wechat-modal-close {
    position: absolute;
    top: 0.5rem;
    right: 0.75rem;
    background: transparent;
    border: 0;
    font-size: 1.6rem;
    line-height: 1;
    color: #888;
    cursor: pointer;
    padding: 0.25rem 0.5rem;
}
.wechat-modal-close:hover { color: #111; }
.wechat-modal-qr {
    width: 220px;
    height: 220px;
    object-fit: contain;
    background: #f2f2f2;
    border: 1px solid #e5e5e5;
    border-radius: 8px;
}
.wechat-modal-qr.missing {
    position: relative;
    background:
      repeating-linear-gradient(45deg, #eee 0 10px, #f6f6f6 10px 20px);
}

@keyframes wechatFadeIn {
    from { opacity: 0; }
    to   { opacity: 1; }
}

/* ====== Terminal-style quote (bold + blinking block cursor) ====== */
.term-quote {
    font-weight: 700;
    font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Monaco, Consolas, "Liberation Mono", "DejaVu Sans Mono", monospace;
    /* 光标紧跟引号末尾,放在 ::after 里 */
}
.term-quote::after {
    content: '';
    display: inline-block;
    width: 0.55em;
    height: 1em;
    margin-left: 0.1em;
    vertical-align: -0.1em;
    background: currentColor;
    animation: term-cursor-blink 1s steps(2, start) infinite;
}
@keyframes term-cursor-blink {
    to { visibility: hidden; }
}
@media (prefers-reduced-motion: reduce) {
    .term-quote::after { animation: none; opacity: 0.8; }
}

/* ====== About: contact email line ====== */
.about-contact {
    margin-top: 1.25rem;
    font-size: 1rem;
    color: var(--color-text-secondary, #aaa);
    line-height: 1.7;
}
.about-contact-email {
    display: inline-block;
    margin-left: 0.4em;
    font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Monaco, Consolas, "Liberation Mono", "DejaVu Sans Mono", monospace;
    font-weight: 700;
    color: #fff;
    text-decoration: none;
    border-bottom: 1px solid rgba(255, 255, 255, 0.4);
    transition: border-color 0.25s ease, color 0.25s ease;
}
.about-contact-email:hover {
    color: #fff;
    border-bottom-color: #fff;
}

/* ====== Mobile fix: engine overlay content was clipped (4th feature invisible) ====== */
@media (max-width: 768px) {
    .engine-overlay {
        /* 覆盖 JS inline 的 align-items:center + padding:8rem 2rem */
        align-items: flex-start !important;
        padding: 5rem 1.25rem 3rem !important;
        overflow-y: auto !important;
        overflow-x: hidden !important;
        -webkit-overflow-scrolling: touch;
    }
    .engine-overlay .container.split {
        width: 100%;
    }
}

/* ====== About: two-column layout (text | turnaround gif) ====== */
.about-grid {
    display: grid;
    /* 左列稍宽以避免 "Twiddle AI" 标题被挤换行; 右列 gif 靠右停靠 */
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
    gap: 4rem;
    align-items: center;
}
.about-text {
    min-width: 0;
}
.about-visual {
    display: flex;
    justify-content: flex-end;  /* gif 在右列内也贴右 */
    align-items: center;
    min-width: 0;
}
.about-visual-img {
    width: 100%;
    max-width: 480px;
    height: auto;
    display: block;
    border-radius: 12px;
}
@media (max-width: 900px) {
    .about-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    .about-visual-img {
        max-width: 360px;
    }
}

/* ================================================================
   Mobile & tablet adaptations (added as one consolidated block)
   ================================================================ */

/* iOS: 输入框字号至少 16px 避免聚焦时自动放大整页 */
.waitlist-input {
    font-size: max(16px, 1rem);
}

/* Prevent horizontal overflow on narrow viewports */
html, body { overflow-x: hidden; }
.term-quote { overflow-wrap: anywhere; }

/* ---- Tablet (769px - 1024px, 主要针对 iPad 竖屏) ---- */
@media (min-width: 769px) and (max-width: 1024px) {
    .section { padding: 5rem 2rem; }
    .section h2 { font-size: clamp(1.8rem, 3.5vw, 2.8rem); }
    .section-desc { font-size: 1.02rem; }
    .container { max-width: 95%; }
    .feature-grid { gap: 1.5rem; }
}

/* ---- Phone (<=768px) extensions on top of existing rule ---- */
@media (max-width: 768px) {
    /* 重建可用的移动端导航:logo 居中,右侧语言切换.省略 nav links */
    .navbar {
        padding: 0.9rem 1.25rem;
    }
    .nav-logo { height: 44px; }
    .nav-logo img { height: 44px; }

    /* Hero: 字号 & 间距 */
    .hero-pretitle {
        font-size: 0.75rem;
        letter-spacing: 0.18em;
    }
    .hero-title { margin-top: 1.25rem; }
    .hero-title h1 { font-size: clamp(2rem, 9vw, 3rem); }
    .hero-subtitle { font-size: 0.95rem; margin-top: 0.8rem; }

    /* Section typography */
    .section { padding: 4rem 1.25rem; }
    .section h2 { font-size: clamp(1.6rem, 7vw, 2.2rem); margin-bottom: 1rem; }
    .section-desc { font-size: 0.98rem; margin-bottom: 2rem; }
    .section-label { font-size: 0.7rem; }

    /* Release: waitlist input full width, button full width below */
    .waitlist-inputs {
        flex-direction: column;
        gap: 0.75rem;
        width: 100%;
        max-width: 360px;
    }
    .waitlist-input { width: 100%; box-sizing: border-box; }
    .waitlist-inputs .cta-button { width: 100%; }

    /* About: reduce visual gif size, stacks already handled by .about-grid */
    .about-visual-img { max-width: 280px; }

    /* Social links row wrap */
    .social-links {
        flex-wrap: wrap;
        gap: 1rem 1.25rem;
        font-size: 0.9rem;
    }

    /* Footer breathing */
    footer { padding: 2rem 1.25rem; font-size: 0.8rem; text-align: center; }

    /* Prevent term-quote cursor from breaking on its own line awkwardly */
    .term-quote::after {
        width: 0.45em;
        height: 0.9em;
    }
}

/* ---- Narrow phone (≤420px) ---- */
@media (max-width: 420px) {
    .hero-title h1 { font-size: 1.9rem; }
    .section h2 { font-size: 1.5rem; }
    .section-desc { font-size: 0.92rem; }
    .about-visual-img { max-width: 240px; }
    .wechat-modal-card { padding: 1.75rem 1.25rem 1.25rem; }
}

/* ---- Landscape phone: hero 不要霸屏 ---- */
@media (max-width: 900px) and (orientation: landscape) and (max-height: 500px) {
    .hero { min-height: auto; padding: 4rem 1rem; }
    .hero-product-wrapper { max-width: 60%; margin: 0 auto; }
}

/* ---- Avoid iOS 100vh jump on hero ---- */
@supports (height: 100svh) {
    .hero { min-height: 100svh; }
}

/* ====== Mobile: restore engine section visibility ======
   Root cause: on desktop, #engine.split-right has height:500px + black bg;
   #engine itself is min-height:100vh + flex:center, which pushes text out of viewport
   on short mobile heights. Also reset any residual inline styles from GSAP init that
   could have been applied in rare race conditions. */
@media (max-width: 768px) {
    #engine {
        min-height: auto;
        padding: 4rem 1.25rem;
        display: block;
    }
    #engine .container.split {
        display: block;
    }
    #engine .split-right {
        height: auto;
        min-height: 260px;
        background: transparent;
        margin-top: 1.5rem;
    }
    #engine .split-right .split-product {
        position: static;
        transform: none;
    }
    /* 显式保证 engine 文字不受 overlay 时间轴的初始 opacity:0 影响 */
    #engine .section-label,
    #engine h2,
    #engine .section-desc,
    #engine .feature-item {
        opacity: 1 !important;
        transform: none !important;
    }
}