/* 昆廷老師個人網站 — 色系 #1F4E79 系列 */
:root {
    --primary: #1F4E79;
    --primary-dark: #15395a;
    --primary-light: #2E6CA8;
    --accent: #C9A96E;        /* 東方金——呼應易經 */
    --accent-dark: #A88A56;
    --ink: #1a2233;
    --ink-soft: #4a5568;
    --ink-mute: #8892a0;
    --bg: #ffffff;
    --bg-alt: #f6f8fb;
    --bg-dark: #0f1a2a;
    --border: #e4e8ef;
    --shadow: 0 4px 20px rgba(31, 78, 121, 0.08);
    --shadow-lg: 0 12px 40px rgba(31, 78, 121, 0.12);
    --radius: 12px;
    --radius-lg: 20px;
    --max-width: 1100px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
    margin: 0;
    font-family: 'Noto Sans TC', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Microsoft JhengHei', sans-serif;
    color: var(--ink);
    background: var(--bg);
    line-height: 1.75;
    letter-spacing: 0.02em;
    -webkit-font-smoothing: antialiased;
}

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

/* ─── Navbar ─── */
.nav {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: saturate(180%) blur(14px);
    -webkit-backdrop-filter: saturate(180%) blur(14px);
    border-bottom: 1px solid var(--border);
}

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

.brand {
    font-family: 'Noto Serif TC', serif;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary);
    text-decoration: none;
    letter-spacing: 0.04em;
}

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

.nav-links a {
    color: var(--ink-soft);
    text-decoration: none;
    font-size: 0.95rem;
    transition: color 0.2s;
}

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

/* ─── Hero ─── */
.hero {
    padding: 120px 0 100px;
    background: linear-gradient(135deg, #f8fafd 0%, #eef3f9 50%, #f5ebd8 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: "";
    position: absolute;
    top: -50%;
    right: -10%;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(201, 169, 110, 0.15), transparent 70%);
    border-radius: 50%;
    pointer-events: none;
}

.hero-eyebrow {
    color: var(--primary);
    font-weight: 500;
    font-size: 0.95rem;
    letter-spacing: 0.15em;
    margin: 0 0 16px;
}

.hero-title {
    font-family: 'Noto Serif TC', serif;
    font-size: clamp(2.4rem, 5vw, 3.8rem);
    font-weight: 700;
    color: var(--primary-dark);
    margin: 0 0 28px;
    line-height: 1.35;
    letter-spacing: 0.02em;
}

.hero-lede {
    font-size: 1.15rem;
    color: var(--ink-soft);
    margin: 0 0 40px;
    max-width: 640px;
    line-height: 2;
}

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

.btn {
    display: inline-flex;
    align-items: center;
    padding: 14px 32px;
    border-radius: 999px;
    font-size: 1rem;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.25s;
    border: 1px solid transparent;
    cursor: pointer;
}

.btn-primary {
    background: var(--primary);
    color: #fff;
}
.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-ghost {
    background: transparent;
    color: var(--primary);
    border-color: var(--primary);
}
.btn-ghost:hover {
    background: var(--primary);
    color: #fff;
}

/* ─── Sections ─── */
.section {
    padding: 100px 0;
}
.section-alt {
    background: var(--bg-alt);
}

.section-title {
    font-family: 'Noto Serif TC', serif;
    font-size: clamp(1.8rem, 3vw, 2.4rem);
    color: var(--primary-dark);
    margin: 0 0 16px;
    text-align: center;
    position: relative;
    padding-bottom: 20px;
}
.section-title::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 48px;
    height: 3px;
    background: var(--accent);
    border-radius: 2px;
}

.section-lede {
    text-align: center;
    color: var(--ink-soft);
    font-size: 1.1rem;
    max-width: 640px;
    margin: 0 auto 56px;
}

.prose {
    max-width: 740px;
    margin: 0 auto;
    font-size: 1.05rem;
    color: var(--ink-soft);
}
.prose p {
    margin: 0 0 24px;
}
.prose strong {
    color: var(--primary);
    font-weight: 600;
}

/* ─── Topics ─── */
.topics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 24px;
    margin-bottom: 60px;
}

.topic-card {
    background: #fff;
    padding: 36px 28px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    transition: all 0.3s;
    border: 1px solid var(--border);
    position: relative;
}
.topic-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
}
.topic-card-highlight {
    border-color: var(--accent);
    background: linear-gradient(135deg, #fff 70%, #fdf7ea 100%);
}

.topic-num {
    font-family: 'Noto Serif TC', serif;
    color: var(--accent);
    font-size: 1.25rem;
    font-weight: 700;
    letter-spacing: 0.1em;
    margin-bottom: 8px;
}

.topic-card h3 {
    font-family: 'Noto Serif TC', serif;
    font-size: 1.3rem;
    color: var(--primary-dark);
    margin: 0 0 16px;
}

.topic-card p {
    color: var(--ink-soft);
    margin: 0;
    font-size: 0.98rem;
    line-height: 1.85;
}

/* ─── Method callout ─── */
.method-callout {
    text-align: center;
    padding: 48px 24px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    color: #fff;
    border-radius: var(--radius-lg);
    max-width: 740px;
    margin: 0 auto;
    box-shadow: var(--shadow-lg);
}
.method-motto {
    font-family: 'Noto Serif TC', serif;
    font-size: clamp(1.3rem, 2.4vw, 1.7rem);
    margin: 0 0 12px;
    letter-spacing: 0.04em;
}
.method-sub {
    color: rgba(255, 255, 255, 0.85);
    margin: 0;
    font-size: 1rem;
}

/* ─── Articles ─── */
.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.article-card {
    background: #fff;
    padding: 32px 28px;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    transition: all 0.25s;
}
.article-card:hover {
    border-color: var(--primary-light);
    transform: translateY(-4px);
    box-shadow: var(--shadow);
}
.article-placeholder {
    opacity: 0.75;
}

.article-meta {
    color: var(--accent-dark);
    font-size: 0.82rem;
    letter-spacing: 0.12em;
    margin-bottom: 12px;
    font-weight: 500;
}

.article-card h3 {
    font-family: 'Noto Serif TC', serif;
    font-size: 1.15rem;
    color: var(--primary-dark);
    margin: 0 0 12px;
    line-height: 1.5;
}
.article-card p {
    color: var(--ink-mute);
    margin: 0;
    font-size: 0.92rem;
}

/* ─── Contact ─── */
.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 20px;
    max-width: 740px;
    margin: 0 auto;
}
.contact-card {
    display: block;
    background: #fff;
    padding: 28px;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    text-decoration: none;
    transition: all 0.25s;
}
.contact-card:hover {
    border-color: var(--accent);
    background: #fffef8;
    transform: translateY(-3px);
}
.contact-label {
    color: var(--accent-dark);
    font-size: 0.82rem;
    letter-spacing: 0.12em;
    margin-bottom: 8px;
    font-weight: 500;
}
.contact-value {
    color: var(--primary-dark);
    font-size: 1.05rem;
    word-break: break-all;
}

/* ─── Footer ─── */
.footer {
    background: var(--bg-dark);
    color: rgba(255, 255, 255, 0.7);
    padding: 60px 0 40px;
    text-align: center;
}
.footer-bio {
    max-width: 680px;
    margin: 0 auto 24px;
    font-size: 0.95rem;
    line-height: 1.9;
}
.footer-copy {
    color: rgba(255, 255, 255, 0.4);
    font-size: 0.85rem;
    margin: 0;
    padding-top: 24px;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
}

/* ─── Responsive ─── */
@media (max-width: 720px) {
    .nav-links { gap: 18px; font-size: 0.9rem; }
    .nav-links a { font-size: 0.88rem; }
    .hero { padding: 80px 0 60px; }
    .section { padding: 72px 0; }
    .hero-cta { flex-direction: column; }
    .btn { width: 100%; justify-content: center; }
    .brand { font-size: 1.1rem; }
}

/* ─── Motion preference ─── */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        transition-duration: 0.01ms !important;
    }
}