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

:root {
    --bg: #fafafa;
    --bg2: #f3f4f6;
    --text: #111827;
    --text2: #4b5563;
    --text3: #9ca3af;
    --border: rgba(0, 0, 0, 0.08);
    --accent: #2563eb;
    --underweight: #60a5fa;
    --normal: #22c55e;
    --overweight: #f59e0b;
    --obese: #ef4444;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: "Space Grotesk", sans-serif;
    background: radial-gradient(circle at top right, rgba(37,99,235,.08), transparent 40%), var(--bg);
    color: var(--text);
    min-height: 100vh;
    font-size: 15px;
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

.container {
    max-width: 680px;
    margin: 0 auto;
    padding: 48px 20px 80px;
}

header {
    margin-bottom: 36px;
}

.logorow {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 8px;
}

.logomark {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border-radius: 12px;
    background: var(--accent);
    box-shadow: 0 8px 20px rgba(37,99,235,.25);
}

.logoText {
    font-size: 22px;
    font-weight: 700;
    letter-spacing: -.04em;
}

.tagline {
    font-size: 15px;
    color: var(--text3);
    line-height: 1.6;
}

.card {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: 24px;
    padding: 28px;
    box-shadow: 0 1px 2px rgba(0,0,0,.02), 0 10px 30px rgba(0,0,0,.04);
    transition: transform .25s ease, box-shadow .25s ease;
}

.card + .card {
    margin-top: 18px;
}

.unitToggle {
    display: flex;
    width: fit-content;
    overflow: hidden;
    border: 1px solid var(--border);
    border-radius: 14px;
    margin-bottom: 28px;
}

.toggleBtn {
    padding: 10px 24px;
    border: none;
    background: transparent;
    font-family: inherit;
    font-size: 14px;
    font-weight: 600;
    color: var(--text2);
    cursor: pointer;
    transition: all .25s ease;
}

.toggleBtn + .toggleBtn {
    border-left: 1px solid var(--border);
}

.toggleBtn.active {
    background: var(--accent);
    color: #fff;
}

.inputGrid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 18px;
}

.inputGroup {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.inputGroup.full {
    grid-column: 1 / -1;
}

label {
    font-size: 12px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .08em;
    color: var(--text3);
}

.inputWrap {
    position: relative;
}

.inputWrap input,
select {
    width: 100%;
    border: 1px solid var(--border);
    border-radius: 14px;
    background: var(--bg2);
    font-family: inherit;
    color: var(--text);
    transition: all .25s ease;
}

.inputWrap input {
    padding: 14px 48px 14px 14px;
    font-size: 16px;
    font-weight: 500;
}

.inputWrap input:focus,
select:focus {
    outline: none;
    background: #fff;
    border-color: var(--accent);
    box-shadow: 0 0 0 4px rgba(37,99,235,.12);
}

.inputWrap input::-webkit-inner-spin-button,
.inputWrap input::-webkit-outer-spin-button {
    -webkit-appearance: none;
}

.inputWrap input {
    -moz-appearance: textfield;
}

.unit-label {
    position: absolute;
    top: 50%;
    right: 14px;
    transform: translateY(-50%);
    color: var(--text3);
    font-size: 13px;
}

.genderRow {
    display: flex;
    gap: 10px;
}

.genderBtn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    flex: 1;
    padding: 12px;
    border: 1px solid var(--border);
    border-radius: 14px;
    background: var(--bg2);
    font-family: inherit;
    font-size: 14px;
    font-weight: 600;
    color: var(--text2);
    cursor: pointer;
    transition: all .25s ease;
}

.genderBtn:hover {
    transform: translateY(-2px);
    border-color: var(--accent);
}

.genderBtn.active {
    background: #eff6ff;
    border-color: var(--accent);
    color: var(--accent);
}

select {
    padding: 14px 38px 14px 14px;
    appearance: none;
    -webkit-appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%23999' stroke-width='1.5' stroke-linecap='round' fill='none'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 14px center;
}

.calcBtn {
    width: 100%;
    height: 56px;
    margin-top: 24px;
    border: none;
    border-radius: 16px;
    background: var(--accent);
    color: #fff;
    font-family: inherit;
    font-size: 15px;
    font-weight: 700;
    cursor: pointer;
    transition: all .25s ease;
}

.calcBtn:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 24px rgba(37,99,235,.18);
}

.results {
    display: none;
}

.results.visible {
    display: block;
}

.gauge-section {
    padding: 10px 0 24px;
    text-align: center;
}

.gaugeWrap {
    position: relative;
    display: inline-block;
}

.gauge-bmi-number {
    position: absolute;
    left: 50%;
    bottom: 28px;
    transform: translateX(-50%);
    font-size: 58px;
    font-weight: 700;
    line-height: 1;
    letter-spacing: -.06em;
}

.gauge-bmi-label {
    position: absolute;
    left: 50%;
    bottom: 8px;
    transform: translateX(-50%);
    font-size: 11px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .1em;
}

.gauge-note {
    margin-top: 8px;
    color: var(--text3);
}

.metricsGrid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 14px;
    margin-top: 24px;
}

.metricCard {
    padding: 18px;
    border: 1px solid var(--border);
    border-radius: 18px;
    background: var(--bg2);
    text-align: center;
    transition: transform .25s ease;
}

.metricCard:hover {
    transform: translateY(-3px);
}

.metricValue {
    font-size: 30px;
    font-weight: 700;
    letter-spacing: -.05em;
}

.metricUnit,
.metricLabel {
    color: var(--text3);
}

.metricLabel {
    margin-top: 6px;
    font-size: 11px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .05em;
}

.infoRows {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-top: 20px;
}

.infoRow {
    display: flex;
    gap: 12px;
    padding: 14px 16px;
    border: 1px solid var(--border);
    border-radius: 16px;
    background: var(--bg2);
}

.infoDot {
    width: 8px;
    height: 8px;
    margin-top: 7px;
    border-radius: 50%;
    flex-shrink: 0;
}

.infoText {
    color: var(--text2);
    line-height: 1.7;
}

.infoText strong {
    color: var(--text);
}

.disclaimer {
    margin-top: 20px;
    text-align: center;
    font-size: 12px;
    color: var(--text3);
}

@media (max-width: 520px) {
    .container {
        padding: 24px 16px 60px;
    }

    .card {
        padding: 20px;
        border-radius: 20px;
    }

    .inputGrid {
        grid-template-columns: 1fr;
    }

    .inputGroup.full {
        grid-column: 1;
    }

    .metricsGrid {
        grid-template-columns: 1fr 1fr;
    }

    .gauge-bmi-number {
        font-size: 46px;
    }
}

@media (prefers-reduced-motion: reduce) {
    * {
        transition: none !important;
        animation: none !important;
    }
}