/* ============================================================
   AgeCalc — Stylesheet
   Design: deep navy/space base · acid amber accent
   Type: DM Mono (data/display) + DM Sans (body/UI)
   ============================================================ */

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

:root {
    /* Palette */
    --bg:         #0a0d14;
    --bg-card:    #0f1320;
    --bg-card2:   #141829;
    --border:     #1e2540;
    --border-hi:  #2c3560;
    --amber:      #f5a623;
    --amber-dim:  #c4841a;
    --amber-glow: rgba(245,166,35,.12);
    --amber-glow2:rgba(245,166,35,.06);
    --text:       #e8ecf5;
    --text-dim:   #7a85a3;
    --text-dimmer:#444e6e;
    --success:    #3dd68c;
    --error:      #f45b5b;
    --white:      #ffffff;

    /* Typography */
    --font-mono: 'DM Mono', 'Courier New', monospace;
    --font-sans: 'DM Sans', system-ui, sans-serif;

    /* Spacing */
    --radius:    12px;
    --radius-sm: 8px;
    --shadow: 0 8px 40px rgba(0,0,0,.45);
}

html { scroll-behavior: smooth; }

body {
    background: var(--bg);
    color: var(--text);
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
}

/* ── Grid background (signature element) ── */
.bg-grid {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 0;
    background-image:
        linear-gradient(var(--border) 1px, transparent 1px),
        linear-gradient(90deg, var(--border) 1px, transparent 1px);
    background-size: 40px 40px;
    mask-image: radial-gradient(ellipse 80% 60% at 50% 20%, black 30%, transparent 100%);
    opacity: .35;
}

/* ── Layout ── */
.container {
    max-width: 780px;
    margin: 0 auto;
    padding: 0 20px;
    position: relative;
    z-index: 1;
}

/* ── Header ── */
.site-header {
    border-bottom: 1px solid var(--border);
    padding: 20px 0;
    position: relative;
    z-index: 1;
}
.site-header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.logo {
    display: flex;
    align-items: center;
    gap: 10px;
}
.logo-mark {
    font-size: 1.4rem;
    color: var(--amber);
    line-height: 1;
}
.logo-text {
    font-family: var(--font-mono);
    font-weight: 500;
    font-size: .95rem;
    letter-spacing: .08em;
    color: var(--text);
}
.tagline {
    font-family: var(--font-mono);
    font-size: .75rem;
    color: var(--text-dimmer);
    letter-spacing: .12em;
    text-transform: uppercase;
}

/* ── Hero ── */
.hero {
    padding: 72px 0 48px;
    text-align: center;
}
.hero-title {
    font-family: var(--font-mono);
    font-size: clamp(2.4rem, 7vw, 4.2rem);
    font-weight: 300;
    line-height: 1.15;
    letter-spacing: -.02em;
    color: var(--text);
    margin-bottom: 20px;
}
.hero-title em {
    font-style: italic;
    color: var(--amber);
    font-weight: 500;
}
.hero-sub {
    max-width: 500px;
    margin: 0 auto;
    color: var(--text-dim);
    font-size: 1rem;
    line-height: 1.65;
}

/* ── Calculator Card ── */
.calc-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 36px 40px 32px;
    box-shadow: var(--shadow);
    margin-bottom: 32px;
}

/* ── Form ── */
.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
    margin-bottom: 28px;
}
.form-group { display: flex; flex-direction: column; gap: 8px; }

.form-label {
    font-family: var(--font-mono);
    font-size: .78rem;
    letter-spacing: .1em;
    text-transform: uppercase;
    color: var(--text-dim);
    display: flex;
    align-items: center;
    gap: 6px;
}
.required { color: var(--amber); }

.optional-badge {
    font-family: var(--font-sans);
    font-size: .68rem;
    background: var(--border);
    color: var(--text-dimmer);
    padding: 2px 7px;
    border-radius: 20px;
    text-transform: none;
    letter-spacing: 0;
    font-weight: 400;
}

.input-wrap {
    position: relative;
    display: flex;
    align-items: center;
}
.input-icon {
    position: absolute;
    left: 14px;
    color: var(--text-dimmer);
    font-size: .9rem;
    pointer-events: none;
    z-index: 1;
    line-height: 1;
}
.form-input {
    width: 100%;
    background: var(--bg);
    border: 1px solid var(--border-hi);
    border-radius: var(--radius-sm);
    padding: 12px 14px 12px 38px;
    color: var(--text);
    font-family: var(--font-mono);
    font-size: .9rem;
    outline: none;
    transition: border-color .2s, box-shadow .2s;
    -webkit-appearance: none;
    appearance: none;
}
.form-input::-webkit-calendar-picker-indicator {
    filter: invert(0.6) sepia(1) saturate(3) hue-rotate(15deg);
    cursor: pointer;
    opacity: .7;
}
.form-input:focus {
    border-color: var(--amber);
    box-shadow: 0 0 0 3px var(--amber-glow);
}
.form-input:hover:not(:focus) { border-color: #3a4266; }

.form-hint {
    font-size: .75rem;
    color: var(--text-dimmer);
    font-family: var(--font-mono);
}

/* ── Buttons ── */
.form-actions {
    display: flex;
    align-items: center;
    gap: 14px;
}
.btn-calculate {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    background: var(--amber);
    color: #0a0d14;
    border: none;
    border-radius: var(--radius-sm);
    padding: 13px 28px;
    font-family: var(--font-mono);
    font-size: .88rem;
    font-weight: 500;
    letter-spacing: .06em;
    cursor: pointer;
    transition: background .18s, transform .15s, box-shadow .18s;
    box-shadow: 0 4px 20px rgba(245,166,35,.25);
}
.btn-calculate:hover {
    background: #f7b740;
    transform: translateY(-1px);
    box-shadow: 0 6px 28px rgba(245,166,35,.4);
}
.btn-calculate:active { transform: translateY(0); }
.btn-arrow { font-size: 1rem; transition: transform .2s; }
.btn-calculate:hover .btn-arrow { transform: translateX(4px); }

.btn-reset {
    background: transparent;
    border: 1px solid var(--border-hi);
    border-radius: var(--radius-sm);
    color: var(--text-dim);
    padding: 12px 20px;
    font-family: var(--font-mono);
    font-size: .82rem;
    letter-spacing: .06em;
    cursor: pointer;
    transition: border-color .18s, color .18s;
}
.btn-reset:hover { border-color: var(--text-dim); color: var(--text); }

/* ── Alerts ── */
.alert {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    border-radius: var(--radius-sm);
    padding: 14px 18px;
    margin-bottom: 24px;
    font-size: .88rem;
}
.alert-error {
    background: rgba(244,91,91,.08);
    border: 1px solid rgba(244,91,91,.3);
    color: #f88;
}
.alert-icon { font-size: 1rem; flex-shrink: 0; margin-top: 2px; }
.alert-list { list-style: none; display: flex; flex-direction: column; gap: 4px; }

/* ── Results section ── */
.results {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    margin-bottom: 48px;
    animation: fadeUp .45s ease both;
}
@keyframes fadeUp {
    from { opacity: 0; transform: translateY(16px); }
    to   { opacity: 1; transform: translateY(0); }
}

.results-header {
    padding: 20px 36px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: var(--bg-card2);
}
.results-label {
    font-family: var(--font-mono);
    font-size: .72rem;
    letter-spacing: .12em;
    text-transform: uppercase;
    color: var(--text-dimmer);
}
.results-dates {
    font-family: var(--font-mono);
    font-size: .82rem;
    color: var(--text-dim);
    display: flex;
    align-items: center;
    gap: 8px;
}
.arrow-span { color: var(--amber); }

/* ── Primary result (Y M D) ── */
.result-primary {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0;
    padding: 48px 36px 24px;
}
.result-unit {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
    flex: 1;
}
.unit-value {
    font-family: var(--font-mono);
    font-size: clamp(2.8rem, 8vw, 5rem);
    font-weight: 300;
    line-height: 1;
    color: var(--text);
    letter-spacing: -.03em;
}
.result-unit[data-unit="years"] .unit-value { color: var(--amber); }
.unit-label {
    font-family: var(--font-mono);
    font-size: .7rem;
    letter-spacing: .14em;
    text-transform: uppercase;
    color: var(--text-dimmer);
}
.result-sep {
    font-family: var(--font-mono);
    font-size: 2.5rem;
    color: var(--border-hi);
    align-self: flex-start;
    margin-top: 8px;
    padding: 0 4px;
}

/* ── Secondary result (H M S) ── */
.result-secondary {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0;
    padding: 0 36px 32px;
}
.result-unit-sm {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    flex: 1;
}
.unit-value-sm {
    font-family: var(--font-mono);
    font-size: clamp(1.4rem, 4vw, 2.2rem);
    font-weight: 300;
    color: var(--text-dim);
    letter-spacing: .02em;
}
.unit-label-sm {
    font-family: var(--font-mono);
    font-size: .62rem;
    letter-spacing: .12em;
    text-transform: uppercase;
    color: var(--text-dimmer);
}
.result-sep-sm {
    font-family: var(--font-mono);
    font-size: 1.4rem;
    color: var(--border-hi);
    align-self: flex-start;
    margin-top: 4px;
    padding: 0 2px;
}

/* ── Live badge ── */
.live-badge {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    font-family: var(--font-mono);
    font-size: .72rem;
    color: var(--success);
    letter-spacing: .1em;
    text-transform: uppercase;
    padding-bottom: 28px;
}
.pulse-dot {
    width: 7px; height: 7px;
    background: var(--success);
    border-radius: 50%;
    display: inline-block;
    animation: pulse 1.4s ease infinite;
}
@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50%       { opacity: .4; transform: scale(.7); }
}

/* ── Totals grid ── */
.totals-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    border-top: 1px solid var(--border);
}
.total-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 22px 16px;
    gap: 5px;
    border-right: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    transition: background .2s;
}
.total-item:nth-child(3n) { border-right: none; }
.total-item:nth-last-child(-n+3) { border-bottom: none; }
.total-item:hover { background: var(--amber-glow2); }
.total-item.highlight { background: var(--amber-glow); }
.total-item.highlight:hover { background: rgba(245,166,35,.18); }
.total-value {
    font-family: var(--font-mono);
    font-size: 1.25rem;
    font-weight: 400;
    color: var(--text);
    letter-spacing: -.01em;
}
.total-item.highlight .total-value { color: var(--amber); }
.total-label {
    font-family: var(--font-mono);
    font-size: .65rem;
    letter-spacing: .1em;
    text-transform: uppercase;
    color: var(--text-dimmer);
}

/* ── Fun facts ── */
.fun-facts {
    padding: 32px 36px;
    border-top: 1px solid var(--border);
    background: var(--bg-card2);
}
.facts-title {
    font-family: var(--font-mono);
    font-size: .72rem;
    letter-spacing: .14em;
    text-transform: uppercase;
    color: var(--text-dimmer);
    margin-bottom: 18px;
}
.facts-grid {
    display: flex;
    flex-direction: column;
    gap: 12px;
}
.fact-item {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    font-size: .88rem;
    color: var(--text-dim);
    line-height: 1.55;
}
.fact-icon {
    color: var(--amber);
    font-size: 1rem;
    flex-shrink: 0;
    margin-top: 1px;
    width: 20px;
    text-align: center;
}

/* ── Next birthday ── */
.next-birthday {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 20px 36px;
    border-top: 1px solid var(--border);
    background: rgba(61,214,140,.04);
}
.nb-label {
    font-family: var(--font-mono);
    font-size: .7rem;
    letter-spacing: .12em;
    text-transform: uppercase;
    color: var(--success);
    flex-shrink: 0;
}
.nb-value {
    font-size: .9rem;
    color: var(--text);
}

/* ── Footer ── */
.site-footer {
    border-top: 1px solid var(--border);
    padding: 24px 0;
    position: relative;
    z-index: 1;
}
.footer-text {
    font-family: var(--font-mono);
    font-size: .72rem;
    color: var(--text-dimmer);
    text-align: center;
    letter-spacing: .05em;
}

/* ── Responsive ── */
@media (max-width: 620px) {
    .calc-card { padding: 24px 20px; }

    .form-row { grid-template-columns: 1fr; gap: 18px; }

    .results-header { flex-direction: column; align-items: flex-start; gap: 6px; padding: 16px 20px; }

    .result-primary { padding: 32px 12px 16px; gap: 0; }
    .result-sep { font-size: 1.8rem; padding: 0 2px; margin-top: 6px; }

    .result-secondary { padding: 0 12px 24px; }
    .result-sep-sm { font-size: 1rem; }

    .totals-grid { grid-template-columns: repeat(2, 1fr); }
    .total-item:nth-child(3n) { border-right: 1px solid var(--border); }
    .total-item:nth-child(2n) { border-right: none; }
    .total-item:nth-last-child(-n+2) { border-bottom: none; }
    .total-item:nth-last-child(3):not(:nth-last-child(1)):not(:nth-last-child(2)) { border-bottom: 1px solid var(--border); }

    .fun-facts { padding: 24px 20px; }
    .next-birthday { padding: 16px 20px; flex-direction: column; align-items: flex-start; gap: 4px; }

    .hero { padding: 48px 0 36px; }
    .hero-title { font-size: 2.2rem; }

    .site-header .container { flex-direction: column; align-items: flex-start; gap: 6px; }
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}

/* ── Scrollbar (WebKit) ── */
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border-hi); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: #3a4570; }