:root {
    --paper: #f4f3ee;
    --surface: #fbfaf6;
    --ink: #1a1c19;
    --muted: #6e6c61;
    --line: #d9d6cb;
    --signal: #0e6e64;
    --signal-warm: #e8432b;
    --radius: 4px;
    --max-width: 900px;
    --nav-height: 60px;
    --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Segoe UI",
        "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    --font-mono: ui-monospace, "SF Mono", "Menlo", "Consolas", "Courier New", monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
    margin: 0;
    font-family: var(--font-sans);
    background-color: var(--paper);
    background-image:
        repeating-linear-gradient(to right, rgba(26, 28, 25, 0.045) 0 1px, transparent 1px 32px),
        repeating-linear-gradient(to bottom, rgba(26, 28, 25, 0.045) 0 1px, transparent 1px 32px);
    color: var(--ink);
    line-height: 1.65;
    -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }

a {
    color: var(--signal);
    text-decoration: none;
}

h1, h2, h3 { line-height: 1.15; margin: 0 0 0.5em; }

a:focus-visible,
button:focus-visible {
    outline: 2px solid var(--signal);
    outline-offset: 2px;
}

/* ===== Header / Nav ===== */
.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(244, 243, 238, 0.9);
    backdrop-filter: saturate(160%) blur(8px);
    border-bottom: 1px solid var(--line);
}

.navbar {
    max-width: var(--max-width);
    height: var(--nav-height);
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    gap: 24px;
}

.brand {
    font-family: var(--font-mono);
    font-weight: 700;
    font-size: 0.82rem;
    letter-spacing: 0.03em;
    color: var(--ink);
    margin-right: auto;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 24px;
    margin: 0;
    padding: 0;
}

.nav-links a {
    font-family: var(--font-mono);
    color: var(--muted);
    font-size: 0.78rem;
    font-weight: 600;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    transition: color 0.15s ease;
}

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

.lang-toggle {
    display: flex;
    align-items: center;
    font-family: var(--font-mono);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: var(--surface);
    padding: 2px;
    font-size: 0.78rem;
    font-weight: 700;
    cursor: pointer;
}

.lang-option {
    padding: 4px 9px;
    border-radius: 2px;
    color: var(--muted);
    transition: background 0.15s ease, color 0.15s ease;
}

.lang-option.active { background: var(--signal); color: var(--surface); }
.lang-sep { display: none; }

.nav-toggle {
    display: none;
    font-family: var(--font-mono);
    font-size: 0.78rem;
    font-weight: 700;
    letter-spacing: 0.04em;
    background: none;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    padding: 6px 10px;
    cursor: pointer;
    color: var(--ink);
}

/* ===== Layout ===== */
main { max-width: var(--max-width); margin: 0 auto; padding: 0 24px; }

.section { padding: 12px 0 56px; }

.section-head {
    display: flex;
    align-items: baseline;
    gap: 14px;
    margin-bottom: 26px;
}

.eyebrow {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    font-weight: 700;
    color: var(--signal);
    letter-spacing: 0.08em;
}

.section h2 {
    font-size: 1.4rem;
    font-weight: 800;
    letter-spacing: -0.01em;
}

/* ===== Section curve dividers ===== */
.section-divider {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
    height: 26px;
    overflow: hidden;
}

.curve-echo {
    width: 100%;
    height: 100%;
    display: block;
}

.curve-echo .curve-path {
    fill: none;
    stroke: var(--line);
    stroke-width: 3;
    stroke-linecap: round;
    stroke-linejoin: round;
}

/* ===== Hero ===== */
.hero { padding: 48px 0 40px; }

.hero-name {
    font-size: clamp(2.4rem, 7vw, 4.2rem);
    font-weight: 800;
    letter-spacing: -0.02em;
    text-transform: uppercase;
    margin: 0 0 18px;
}

.hero-field {
    display: flex;
    flex-wrap: wrap;
    align-items: baseline;
    gap: 10px;
    margin: 0 0 28px;
    font-size: 1.05rem;
}

.field-label {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    font-weight: 700;
    color: var(--signal);
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

.field-value { color: var(--ink); }

.curve-wrap {
    height: clamp(110px, 16vw, 160px);
    width: 100%;
    margin: 0 0 32px;
}

.hero-curve { width: 100%; height: 100%; display: block; }

.hero-curve .curve-path {
    fill: none;
    stroke: var(--signal);
    stroke-width: 3.5;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.curve-peak {
    fill: var(--signal-warm);
    offset-path: path("M0,140 L70,140 C105,140 115,168 150,168 C185,168 190,55 250,35 C280,25 295,150 345,185 L455,185 C475,185 480,20 500,20 C515,20 520,150 540,150 C555,150 560,140 580,140 L800,140");
    offset-rotate: 0deg;
    animation: curve-dot-travel 16s linear infinite;
}

@keyframes curve-dot-travel {
    from { offset-distance: 0%; }
    to { offset-distance: 100%; }
}

@media (prefers-reduced-motion: reduce) {
    .curve-peak { animation: none; offset-distance: 45%; }
}

.hero-links {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.field-row {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    border: 1px solid var(--line);
    background: var(--surface);
    padding: 9px 14px;
    border-radius: var(--radius);
    font-family: var(--font-mono);
    font-size: 0.82rem;
    color: var(--ink);
    transition: border-color 0.15s ease;
}

.field-row:hover { border-color: var(--signal); color: var(--signal); }

.icon {
    width: 16px;
    height: 16px;
    flex-shrink: 0;
}

.icon-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 38px;
    height: 38px;
    border: 1px solid var(--line);
    background: var(--surface);
    border-radius: var(--radius);
    color: var(--ink);
    transition: border-color 0.15s ease, color 0.15s ease;
}

.icon-link .icon { width: 18px; height: 18px; }

.icon-link:hover { border-color: var(--signal); color: var(--signal); }

/* ===== Ledger (Experience) ===== */
.ledger-group-title {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--muted);
    margin: 0 0 10px;
}

.ledger + .ledger-group-title { margin-top: 36px; }

.ledger {
    list-style: none;
    margin: 0;
    padding: 0;
    border-top: 1px solid var(--line);
}

.ledger-row {
    display: grid;
    grid-template-columns: 150px 1fr;
    gap: 24px;
    padding: 20px 16px;
    border-bottom: 1px solid var(--line);
}

.ledger-row:nth-child(even) { background: var(--surface); }

.ledger-date {
    font-family: var(--font-mono);
    font-size: 0.82rem;
    color: var(--muted);
    padding-top: 2px;
}

.ledger-body h4 { font-size: 1.02rem; margin: 0 0 0.5em; }

.ledger-body ul {
    margin: 8px 0 0;
    padding-left: 20px;
    color: var(--ink);
    opacity: 0.82;
}

.ledger-body li { margin-bottom: 4px; font-size: 0.92rem; }

/* ===== Report cards (Projects) ===== */
.report-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
}

.report-card {
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    padding: 22px;
    display: flex;
    flex-direction: column;
    gap: 8px;
    transition: border-color 0.15s ease, transform 0.15s ease;
}

.report-card:hover {
    border-color: var(--signal);
    transform: translateY(-2px);
}

.report-tag {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    font-weight: 700;
    color: var(--signal);
    letter-spacing: 0.08em;
}

.report-card h3 { font-size: 1.08rem; }

.meta-row {
    display: flex;
    flex-wrap: wrap;
    gap: 18px;
    font-family: var(--font-mono);
    font-size: 0.76rem;
    color: var(--muted);
}

.meta-row .field-label { margin-right: 4px; }

.hairline {
    border: none;
    border-top: 1px solid var(--line);
    margin: 2px 0 4px;
}

.report-card p {
    font-size: 0.92rem;
    color: var(--ink);
    opacity: 0.85;
    flex-grow: 1;
}

/* ===== Nameplate tags ===== */
.tag-list {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin: 4px 0 0;
}

.tag {
    display: inline-block;
    border: 1px solid var(--line);
    background: transparent;
    color: var(--signal);
    font-family: var(--font-mono);
    font-size: 0.7rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    padding: 4px 10px;
    border-radius: 3px;
}

/* ===== Skills ===== */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 28px;
}

.skill-group h3 {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--muted);
    margin-bottom: 10px;
}

/* ===== Footer ===== */
.site-footer {
    text-align: center;
    padding: 48px 24px 40px;
    border-top: 1px solid var(--line);
    color: var(--muted);
}

.footer-head { justify-content: center; margin-bottom: 20px; }

.contact-form {
    max-width: 440px;
    margin: 28px auto 0;
    display: flex;
    flex-direction: column;
    gap: 16px;
    text-align: left;
}

.form-field {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.form-field input,
.form-field textarea {
    font-family: var(--font-sans);
    font-size: 0.92rem;
    color: var(--ink);
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    padding: 10px 12px;
    resize: vertical;
}

.form-field input:focus,
.form-field textarea:focus {
    outline: none;
    border-color: var(--signal);
}

.submit-btn {
    align-self: flex-start;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    color: var(--surface);
    background: var(--signal);
    border: none;
    border-radius: var(--radius);
    padding: 11px 22px;
    cursor: pointer;
    transition: opacity 0.15s ease;
}

.submit-btn:hover { opacity: 0.85; }

.sign-off {
    font-family: var(--font-mono);
    letter-spacing: 0.16em;
    color: var(--muted);
    font-size: 0.8rem;
    margin-top: 28px;
}

.copyright { margin-top: 10px; font-size: 0.8rem; }

/* ===== Responsive ===== */
@media (max-width: 720px) {
    .nav-toggle { display: block; }

    .nav-links {
        position: absolute;
        top: var(--nav-height);
        left: 0;
        right: 0;
        background: var(--paper);
        border-bottom: 1px solid var(--line);
        flex-direction: column;
        gap: 0;
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.25s ease;
    }

    .nav-links.open { max-height: 320px; }

    .nav-links li { border-top: 1px solid var(--line); }

    .nav-links a {
        display: block;
        padding: 14px 24px;
    }

    .ledger-row { grid-template-columns: 1fr; gap: 6px; }

    .hero-name { font-size: clamp(2rem, 10vw, 3rem); }
}