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

:root {
    --bg: #0c0c12;
    --card: rgba(255,255,255,0.05);

    --border: rgba(255,255,255,0.12);
    --border-hover: rgba(255,255,255,0.22);
    --text: #f0f0f3;
    --text-dim: #b0b0c0;
    --text-mid: #d0d0dc;
    --accent: #2ecfef;
    --accent2: #a040f0;
    --nav-bg: rgba(12,12,18,0.7);
    --h1-grad: linear-gradient(135deg, #fff 0%, #e0f9ff 25%, #2ecfef 58%, #a040f0 100%);
    --hero-bg: linear-gradient(160deg, #071e30 0%, #0c0c12 55%, #13082a 100%);
    --btn2-bg: rgba(255,255,255,0.04);
    --btn2-hover: rgba(255,255,255,0.08);
}

[data-theme="light"] {
    --bg: #f8f9fb;
    --card: rgba(0,0,0,0.02);

    --border: rgba(0,0,0,0.08);
    --border-hover: rgba(0,0,0,0.15);
    --text: #111827;
    --text-dim: #4b5563;
    --text-mid: #374151;
    --accent: #1490b0;
    --accent2: #7020b0;
    --nav-bg: rgba(248,249,251,0.75);
    --h1-grad: linear-gradient(135deg, #111827 0%, #111827 20%, #1490b0 58%, #7020b0 100%);
    --hero-bg: linear-gradient(160deg, #dff4fb 0%, #f8f9fb 50%, #ede8fc 100%);
    --btn2-bg: rgba(0,0,0,0.03);
    --btn2-hover: rgba(0,0,0,0.06);
}

body {
    font-family: 'Inter', -apple-system, sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    overflow-x: hidden;
    transition: background 0.3s, color 0.3s;
}

/* 導航 */
.nav {
    position: fixed; top: 0; left: 0; right: 0; z-index: 100;
    padding: 1.25rem 2.5rem;
    display: flex; align-items: center; justify-content: space-between;
    backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px);
    background: var(--nav-bg);
    border-bottom: 1px solid var(--border);
    transition: background 0.3s;
}
.nav-logo {
    display: flex; align-items: center; gap: 0.6rem;
    font-weight: 700; font-size: 1.15rem; letter-spacing: -0.02em;
    text-decoration: none; color: var(--text);
}
.nav-logo-img { height: 48px; width: auto; object-fit: contain; }
.nav-right { display: flex; align-items: center; gap: 0.75rem; }
.nav-btn {
    background: var(--btn2-bg); border: 1px solid var(--border);
    color: var(--text-dim); padding: 0.4rem 0.65rem; border-radius: 8px;
    cursor: pointer; font-size: 0.8rem; font-weight: 500;
    transition: all 0.2s; font-family: inherit;
    display: flex; align-items: center; justify-content: center;
}
.nav-btn:hover { border-color: var(--border-hover); color: var(--text); background: var(--btn2-hover); }
.nav-btn svg { width: 16px; height: 16px; }
.lang-btn { padding: 0.4rem 0.85rem; }

.page { position: relative; z-index: 1; }

/* Hero */
.hero-wrap {
    position: relative;
    overflow: hidden;
    background-color: #0f1e38;
    background-image: url('/static/hero-bg.svg');
    background-size: cover;
    background-position: center top;
    background-repeat: no-repeat;
}
/* Hero 背景永遠深色，強制白色文字 */
.hero-wrap .hero-sub { color: rgba(255,255,255,0.75); }
.hero-wrap h1 {
    background: linear-gradient(135deg, #fff 0%, #e0f9ff 25%, #2ecfef 58%, #a040f0 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.hero { position: relative; z-index: 1; padding: 8rem 2rem 3rem; max-width: 800px; margin: 0 auto; text-align: center; }
.hero-col { display: flex; flex-direction: column; align-items: center; }
h1 {
    font-size: 4rem; font-weight: 800; line-height: 1.05;
    letter-spacing: -0.04em; margin-bottom: 1.5rem;
    background: var(--h1-grad);
    -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.hero-sub {
    font-size: 1.15rem; color: var(--text-dim); line-height: 1.6;
    max-width: 560px; font-weight: 400;
}
/* 特性區 */
.features { max-width: 1100px; margin: 0 auto; padding: 2rem 2rem 3rem; }
.features-inner {
    background: var(--card); border: 1px solid var(--border);
    border-radius: 20px; padding: 2.5rem;
    position: relative; overflow: hidden;
}
.features-inner::before {
    content: ''; position: absolute; top: 0; left: 50%; transform: translateX(-50%);
    width: 300px; height: 1px;
    background: linear-gradient(90deg, transparent, var(--accent), transparent);
}
.features-row { display: grid; grid-template-columns: repeat(3, 1fr); gap: 2.5rem; }
.feature-icon { font-size: 1.5rem; margin-bottom: 0.75rem; }
.feature h3 { font-size: 1.1rem; font-weight: 600; margin-bottom: 0.5rem; letter-spacing: -0.01em; }
.feature p { color: var(--text-dim); font-size: 0.9rem; line-height: 1.6; }
.sec-row {
    display: flex; justify-content: center; gap: 2.5rem; flex-wrap: wrap;
    margin-top: 2rem; padding-top: 1.75rem;
    border-top: 1px solid var(--border);
}
.sec-tag { display: flex; align-items: center; gap: 0.45rem; }
.sec-icon { font-size: 1.1rem; }
.sec-tag span:last-child { font-size: 0.85rem; color: var(--text-mid); font-weight: 500; }

/* 平台下載區 */
.platforms-divider {
    margin-top: 2rem; padding-top: 0;
    border-top: 1px solid var(--border);
}
.platforms-section { margin-top: 2rem; }
.platforms-section h2 { font-size: 1.5rem; font-weight: 700; margin-bottom: 1.5rem; letter-spacing: -0.02em; text-align: center; }
.platforms-row {
    display: flex; justify-content: center; gap: 1.5rem; flex-wrap: wrap;
}
.platform-card {
    display: flex; flex-direction: column; align-items: center; gap: 0.5rem;
    padding: 1.5rem 2rem; border-radius: 14px;
    background: var(--card); border: 1px solid var(--border);
    transition: all 0.3s; min-width: 120px;
}
.platform-card:hover { border-color: var(--border-hover); transform: translateY(-2px); }
a.platform-card { text-decoration: none; color: inherit; }
.platform-card-active { border-color: var(--accent); }
.platform-card-active:hover { border-color: var(--accent); }
.platform-icon { width: 32px; height: 32px; color: var(--text); }
.platform-name { font-size: 0.9rem; font-weight: 600; }
.platform-note { font-size: 0.75rem; color: var(--text-dim); }

@media (max-width: 768px) {
    .features { padding: 1.5rem 1.5rem 2rem; }
    .features-inner { padding: 2rem 1.5rem; }
    .features-row { grid-template-columns: 1fr; gap: 2rem; }
    .sec-row { gap: 1rem 2rem; }
    .hero { padding: 6rem 1.5rem 2rem; }
    h1 { font-size: 2.75rem; }
    .hero-sub { font-size: 1.05rem; }
    .platforms-row { gap: 1rem; }
    .platform-card { padding: 1.25rem 1.5rem; min-width: 100px; }
}

/* Footer */
footer {
    max-width: 1100px; margin: 0 auto; padding: 2rem 2rem 3rem;
    border-top: 1px solid var(--border);
    display: flex; align-items: center; justify-content: space-between;
}
@media (max-width: 768px) { footer { flex-direction: column; gap: 1rem; text-align: center; } }
.footer-links { display: flex; gap: 1.5rem; }
.footer-links a { color: var(--text-dim); text-decoration: none; font-size: 0.85rem; transition: color 0.2s; }
.footer-links a:hover { color: var(--text); }
.copyright { color: var(--text-dim); font-size: 0.8rem; }

/* 淡入動畫 */
.fade-in { opacity: 0; transform: translateY(20px); transition: opacity 0.6s ease, transform 0.6s ease; }
.fade-in.visible { opacity: 1; transform: translateY(0); }