/* ========================================
   KnowDays Landing — Eastern Void Aesthetic
   ======================================== */

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

:root {
    --bg: #0A0A0F;
    --bg-alt: #0F0F16;
    --text: #E8E6E1;
    --text-dim: #6B6B7B;
    --gold: #C9A84C;
    --gold-dim: rgba(201, 168, 76, 0.4);
    --gold-glow: rgba(201, 168, 76, 0.25);
    --content-w: 680px;
    --section-pad: 120px;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    background: var(--bg);
    color: var(--text);
    font-family: 'Inter', sans-serif;
    font-weight: 300;
    line-height: 1.9;
    overflow-x: hidden;
}

/* --- Font Stacks per Language --- */
[lang="en"] { font-family: 'Inter', sans-serif; }
[lang="zhTW"], [lang="zh-TW"] { font-family: 'Noto Serif TC', serif; }
[lang="ja"] { font-family: 'Noto Serif JP', serif; }
[lang="id"] { font-family: 'Inter', sans-serif; }

/* Serif headings for all languages */
.brand-name, .feature-name, .transition-text, .cta-text, .highlight-line {
    font-family: 'Cormorant Garamond', 'Noto Serif TC', 'Noto Serif JP', serif;
    font-weight: 300;
}

[lang="zhTW"] .brand-name,
[lang="zhTW"] .feature-name,
[lang="zhTW"] .transition-text,
[lang="zhTW"] .cta-text,
[lang="zhTW"] .highlight-line {
    font-family: 'Noto Serif TC', serif;
}

[lang="ja"] .brand-name,
[lang="ja"] .feature-name,
[lang="ja"] .transition-text,
[lang="ja"] .cta-text,
[lang="ja"] .highlight-line {
    font-family: 'Noto Serif JP', serif;
}

/* --- Language Switcher --- */
.lang-nav {
    position: fixed;
    top: 24px;
    right: 24px;
    z-index: 100;
    display: flex;
    align-items: center;
    gap: 6px;
    opacity: 0;
    animation: fadeIn 1.5s ease 2s forwards;
}

.lang-btn {
    background: none;
    border: none;
    color: var(--text-dim);
    font-family: 'Inter', sans-serif;
    font-size: 11px;
    font-weight: 300;
    letter-spacing: 0.05em;
    cursor: pointer;
    padding: 4px 6px;
    transition: color 0.4s ease;
}

.lang-btn:hover,
.lang-btn.active {
    color: var(--gold);
}

.lang-sep {
    color: rgba(201, 168, 76, 0.2);
    font-size: 8px;
}

/* --- Hero --- */
.hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    position: relative;
    padding: 60px 24px;
}

.hero-inner {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 32px;
}

.logo-wrap {
    opacity: 0;
    animation: fadeIn 3s ease 0.3s forwards;
}

.logo-mark {
    display: block;
}

.brand-name {
    font-size: 28px;
    letter-spacing: 0.3em;
    text-transform: uppercase;
    color: var(--text);
    opacity: 0;
    animation: fadeIn 2s ease 0.8s forwards;
}

.hero-slogan {
    font-size: 15px;
    letter-spacing: 0.12em;
    color: var(--text-dim);
    opacity: 0;
    animation: fadeIn 2s ease 1.8s forwards;
}

/* Scroll Hint */
.scroll-hint {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    opacity: 0;
    animation: fadeIn 1.5s ease 3s forwards;
}

.scroll-line {
    width: 1px;
    height: 32px;
    background: var(--gold-dim);
    animation: scrollFloat 2.5s ease-in-out infinite;
}

@keyframes scrollFloat {
    0%, 100% { transform: translateY(0); opacity: 0.4; }
    50% { transform: translateY(8px); opacity: 0.8; }
}

/* --- Transition Section --- */
.transition-section {
    min-height: 50vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--section-pad) 24px;
}

.transition-text {
    font-size: 22px;
    letter-spacing: 0.15em;
    color: var(--text-dim);
    text-align: center;
}

/* --- Feature Sections --- */
.feature {
    min-height: 80vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--section-pad) 24px;
}

.feature-inner {
    max-width: var(--content-w);
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: 40px;
}

.feature-content {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.feature-icon {
    color: var(--gold);
    opacity: 0.5;
    animation: breathe 4s ease-in-out infinite;
}

.feature-name {
    font-size: 22px;
    letter-spacing: 0.2em;
    color: var(--text);
}

.feature-desc {
    font-size: 15px;
    letter-spacing: 0.08em;
    color: var(--text-dim);
    line-height: 2;
    max-width: 420px;
}

@keyframes breathe {
    0%, 100% { opacity: 0.35; }
    50% { opacity: 0.65; }
}

/* --- Highlights --- */
.highlights {
    min-height: 80vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--section-pad) 24px;
    gap: 100px;
}

.highlight-line {
    font-size: 18px;
    letter-spacing: 0.12em;
    color: var(--gold-dim);
    text-align: center;
    max-width: var(--content-w);
}

/* --- CTA --- */
.cta {
    min-height: 70vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--section-pad) 24px;
    gap: 60px;
}

.cta-text {
    font-size: 24px;
    letter-spacing: 0.15em;
    color: var(--text);
    text-align: center;
}

.cta-buttons {
    display: flex;
    gap: 24px;
}

.store-btn {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 14px 28px;
    border: 1px solid var(--gold-dim);
    border-radius: 4px;
    color: var(--gold);
    text-decoration: none;
    font-size: 13px;
    letter-spacing: 0.08em;
    transition: border-color 0.4s ease, box-shadow 0.4s ease;
}

.store-btn:hover {
    border-color: var(--gold);
    box-shadow: 0 0 16px var(--gold-glow);
}

.store-btn svg {
    flex-shrink: 0;
}

/* --- Footer --- */
.footer {
    padding: 60px 24px;
    text-align: center;
}

.footer p {
    font-size: 12px;
    color: var(--text-dim);
    letter-spacing: 0.05em;
    opacity: 0.6;
}

.footer a {
    color: var(--text-dim);
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer a:hover {
    color: var(--gold);
}

/* --- Scroll Reveal --- */
.reveal {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}

.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

/* --- Animations --- */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* --- Reduced Motion --- */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    .reveal { opacity: 1; transform: none; }
    .logo-wrap, .brand-name, .hero-slogan, .lang-nav, .scroll-hint {
        opacity: 1; transform: none;
    }
}

/* --- SEO Content (visually hidden, crawlable) --- */
.seo-content {
    position: absolute !important;
    width: 1px !important;
    height: 1px !important;
    padding: 0 !important;
    margin: -1px !important;
    overflow: hidden !important;
    clip: rect(0, 0, 0, 0) !important;
    white-space: nowrap !important;
    border: 0 !important;
}

/* --- Responsive: Tablet+ --- */
@media (min-width: 768px) {
    .feature-inner {
        flex-direction: row;
        text-align: left;
        gap: 60px;
    }

    .feature-icon {
        flex-shrink: 0;
    }

    .feature-content {
        gap: 20px;
    }

    .highlight-line {
        font-size: 20px;
    }

    .cta-text {
        font-size: 28px;
    }
}

/* --- Responsive: Desktop --- */
@media (min-width: 1024px) {
    :root {
        --section-pad: 160px;
    }

    .brand-name {
        font-size: 32px;
    }

    .transition-text {
        font-size: 26px;
    }

    .feature-name {
        font-size: 24px;
    }

    .feature-desc {
        font-size: 16px;
    }
}