/* ===================================
   CSS Variables & Design Tokens
=================================== */
:root {
    --color-bg: #0f0c29;
    --color-bg-mid: #302b63;
    --color-bg-end: #24243e;

    --color-card-bg: rgba(255, 255, 255, 0.07);
    --color-card-border: rgba(255, 255, 255, 0.12);

    --color-text-primary: #f0f0f0;
    --color-text-secondary: rgba(240, 240, 240, 0.6);
    --color-text-muted: rgba(240, 240, 240, 0.35);

    --color-input-bg: rgba(255, 255, 255, 0.06);
    --color-input-border: rgba(255, 255, 255, 0.15);
    --color-input-focus-border: rgba(130, 100, 255, 0.8);
    --color-input-focus-shadow: rgba(130, 100, 255, 0.25);

    --color-btn-from: #7c3aed;
    --color-btn-to: #a855f7;
    --color-btn-hover-from: #6d28d9;
    --color-btn-hover-to: #9333ea;

    --color-underweight: #3b82f6;
    --color-underweight-bg: rgba(59, 130, 246, 0.15);
    --color-normal: #22c55e;
    --color-normal-bg: rgba(34, 197, 94, 0.15);
    --color-overweight: #f97316;
    --color-overweight-bg: rgba(249, 115, 22, 0.15);
    --color-obese: #ef4444;
    --color-obese-bg: rgba(239, 68, 68, 0.15);

    --color-error: #f87171;

    --radius-sm: 8px;
    --radius-md: 14px;
    --radius-lg: 24px;
    --radius-xl: 32px;
    --radius-pill: 999px;

    --shadow-card: 0 25px 60px rgba(0, 0, 0, 0.5), 0 0 0 1px rgba(255, 255, 255, 0.08);
    --shadow-input-focus: 0 0 0 3px var(--color-input-focus-shadow);
    --shadow-btn: 0 8px 30px rgba(124, 58, 237, 0.5);
    --shadow-btn-hover: 0 12px 40px rgba(124, 58, 237, 0.7);

    --transition-fast: 0.18s ease;
    --transition-smooth: 0.3s ease;
    --transition-bounce: 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: "Inter", system-ui, -apple-system, sans-serif;
    background: linear-gradient(135deg, var(--color-bg), var(--color-bg-mid), var(--color-bg-end));
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text-primary);
    overflow-x: hidden;
    position: relative;
}

/* ===================================
   Animated Background Blobs
=================================== */
.background-blobs {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 0;
    overflow: hidden;
}

.blob {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.2;
    animation: blobFloat 12s ease-in-out infinite alternate;
}

.blob-1 {
    width: 450px;
    height: 450px;
    background: radial-gradient(circle, #7c3aed, #4338ca);
    top: -120px;
    left: -120px;
    animation-duration: 14s;
}

.blob-2 {
    width: 350px;
    height: 350px;
    background: radial-gradient(circle, #a855f7, #6366f1);
    bottom: -100px;
    right: -100px;
    animation-duration: 10s;
    animation-direction: alternate-reverse;
}

.blob-3 {
    width: 250px;
    height: 250px;
    background: radial-gradient(circle, #3b82f6, #06b6d4);
    top: 50%;
    right: 20%;
    animation-duration: 16s;
}

@keyframes blobFloat {
    0% {
        transform: translate(0, 0) scale(1);
    }

    33% {
        transform: translate(30px, -40px) scale(1.05);
    }

    66% {
        transform: translate(-20px, 20px) scale(0.97);
    }

    100% {
        transform: translate(40px, 30px) scale(1.03);
    }
}

/* ===================================
   Layout Container
=================================== */
.container {
    position: relative;
    z-index: 1;
    width: 100%;
    max-width: 480px;
    padding: 16px;
    margin: 40px auto;
}

/* ===================================
   Glassmorphism Card
=================================== */
.card {
    background: var(--color-card-bg);
    border: 1px solid var(--color-card-border);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-card);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    padding: 40px 36px;
    animation: cardEntrance 0.6s cubic-bezier(0.34, 1.3, 0.64, 1) both;
}

@keyframes cardEntrance {
    from {
        opacity: 0;
        transform: translateY(32px) scale(0.96);
    }

    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

/* ===================================
   Card Header
=================================== */
.card-header {
    text-align: center;
    margin-bottom: 36px;
}

.icon-wrapper {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 64px;
    height: 64px;
    background: linear-gradient(135deg, var(--color-btn-from), var(--color-btn-to));
    border-radius: var(--radius-md);
    color: #fff;
    margin-bottom: 16px;
    box-shadow: 0 8px 24px rgba(124, 58, 237, 0.45);
    animation: iconPulse 3s ease-in-out infinite;
}

@keyframes iconPulse {

    0%,
    100% {
        box-shadow: 0 8px 24px rgba(124, 58, 237, 0.45);
    }

    50% {
        box-shadow: 0 8px 36px rgba(168, 85, 247, 0.65);
    }
}

.card-title {
    font-size: 1.9rem;
    font-weight: 800;
    background: linear-gradient(to right, #e0c3fc, #8ec5fc);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.5px;
    margin-bottom: 6px;
}

.card-subtitle {
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    font-weight: 400;
}

/* ===================================
   Form & Input Groups
=================================== */
.bmi-form {
    display: flex;
    flex-direction: column;
    gap: 22px;
}

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

.input-label {
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--color-text-secondary);
    letter-spacing: 0.6px;
    text-transform: uppercase;
    display: flex;
    align-items: center;
    gap: 6px;
}

.label-icon {
    font-size: 1rem;
}

.input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

.input-field {
    width: 100%;
    padding: 14px 60px 14px 18px;
    background: var(--color-input-bg);
    border: 1.5px solid var(--color-input-border);
    border-radius: var(--radius-md);
    color: var(--color-text-primary);
    font-size: 1rem;
    font-family: inherit;
    font-weight: 500;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast),
        background var(--transition-fast);
    outline: none;
    -moz-appearance: textfield;
    appearance: textfield;
}

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

.input-field::placeholder {
    color: var(--color-text-muted);
    font-weight: 400;
}

.input-field:focus {
    border-color: var(--color-input-focus-border);
    box-shadow: var(--shadow-input-focus);
    background: rgba(255, 255, 255, 0.09);
}

.input-field.input-error {
    border-color: var(--color-error);
    box-shadow: 0 0 0 3px rgba(248, 113, 113, 0.2);
}

.input-unit {
    position: absolute;
    right: 16px;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--color-text-muted);
    pointer-events: none;
    letter-spacing: 0.5px;
}

.error-msg {
    font-size: 0.78rem;
    color: var(--color-error);
    font-weight: 500;
    min-height: 18px;
    padding-left: 4px;
    opacity: 0;
    transform: translateY(-4px);
    transition: opacity var(--transition-fast), transform var(--transition-fast);
}

.error-msg.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===================================
   Calculate Button
=================================== */
.calculate-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    width: 100%;
    padding: 15px 24px;
    background: linear-gradient(135deg, var(--color-btn-from), var(--color-btn-to));
    color: #fff;
    font-size: 1rem;
    font-weight: 700;
    font-family: inherit;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    letter-spacing: 0.3px;
    box-shadow: var(--shadow-btn);
    transition: transform var(--transition-smooth), box-shadow var(--transition-smooth),
        background var(--transition-smooth);
    margin-top: 6px;
    position: relative;
    overflow: hidden;
}

.calculate-btn::before {
    content: "";
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, var(--color-btn-hover-from), var(--color-btn-hover-to));
    opacity: 0;
    transition: opacity var(--transition-smooth);
}

.calculate-btn:hover::before {
    opacity: 1;
}

.calculate-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-btn-hover);
}

.calculate-btn:active {
    transform: translateY(0px) scale(0.98);
}

.btn-text {
    position: relative;
    z-index: 1;
}

.btn-icon {
    position: relative;
    z-index: 1;
    font-size: 1.1rem;
    transition: transform var(--transition-smooth);
}

.calculate-btn:hover .btn-icon {
    transform: translateX(4px);
}

/* ===================================
   Result Section
=================================== */
.result-section {
    display: flex;
    flex-direction: column;
    gap: 24px;
    animation: resultReveal 0.5s cubic-bezier(0.34, 1.4, 0.64, 1) both;
}

.result-section.hidden {
    display: none;
}

@keyframes resultReveal {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.result-divider {
    height: 1px;
    background: linear-gradient(to right, transparent, rgba(255, 255, 255, 0.12), transparent);
    margin-top: 8px;
}

/* ===================================
   Result Card
=================================== */
.result-card {
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
}

/* Age Group Chip */
.age-group-chip {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    padding: 3px 12px;
    border-radius: var(--radius-pill);
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.3px;
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.14);
    color: var(--color-text-secondary);
    transition: all var(--transition-smooth);
}

.age-group-chip:empty {
    display: none;
}

/* Age Note (disclaimer for children / seniors) */
.age-note {
    font-size: 0.76rem;
    font-weight: 500;
    color: rgba(253, 224, 71, 0.85);
    /* amber-ish warning tone */
    text-align: center;
    padding: 6px 10px;
    background: rgba(253, 224, 71, 0.07);
    border: 1px solid rgba(253, 224, 71, 0.15);
    border-radius: var(--radius-sm);
    line-height: 1.4;
    transition: all var(--transition-smooth);
}

.age-note:empty {
    display: none;
}

.result-label {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.result-value-wrapper {
    display: flex;
    align-items: baseline;
    gap: 4px;
}

.result-value {
    font-size: 4.5rem;
    font-weight: 800;
    line-height: 1;
    letter-spacing: -2px;
    transition: color var(--transition-smooth);
    animation: numberCount 0.6s cubic-bezier(0.34, 1.3, 0.64, 1) both;
}

@keyframes numberCount {
    from {
        transform: scale(0.5);
        opacity: 0;
    }

    to {
        transform: scale(1);
        opacity: 1;
    }
}

/* Color states for result-value */
.result-value.color-underweight {
    color: var(--color-underweight);
}

.result-value.color-normal {
    color: var(--color-normal);
}

.result-value.color-overweight {
    color: var(--color-overweight);
}

.result-value.color-obese {
    color: var(--color-obese);
}

/* ===================================
   BMI Category Badge
=================================== */
.bmi-badge {
    display: inline-flex;
    align-items: center;
    padding: 6px 18px;
    border-radius: var(--radius-pill);
    font-size: 0.9rem;
    font-weight: 600;
    transition: background var(--transition-smooth), color var(--transition-smooth),
        border-color var(--transition-smooth);
    border: 1.5px solid transparent;
    animation: badgePop 0.5s var(--transition-bounce) both 0.1s;
}

@keyframes badgePop {
    from {
        transform: scale(0.6);
        opacity: 0;
    }

    to {
        transform: scale(1);
        opacity: 1;
    }
}

.bmi-badge.badge-underweight {
    color: var(--color-underweight);
    background: var(--color-underweight-bg);
    border-color: rgba(59, 130, 246, 0.3);
}

.bmi-badge.badge-normal {
    color: var(--color-normal);
    background: var(--color-normal-bg);
    border-color: rgba(34, 197, 94, 0.3);
}

.bmi-badge.badge-overweight {
    color: var(--color-overweight);
    background: var(--color-overweight-bg);
    border-color: rgba(249, 115, 22, 0.3);
}

.bmi-badge.badge-obese {
    color: var(--color-obese);
    background: var(--color-obese-bg);
    border-color: rgba(239, 68, 68, 0.3);
}

/* ===================================
   BMI Scale Bar
=================================== */
.bmi-scale {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.scale-bar {
    position: relative;
    display: flex;
    border-radius: var(--radius-pill);
    overflow: visible;
    height: 10px;
}

.scale-segment {
    flex: 1;
    height: 100%;
    transition: filter var(--transition-smooth);
}

.scale-segment:first-child {
    border-radius: var(--radius-pill) 0 0 var(--radius-pill);
}

.scale-segment:last-child {
    border-radius: 0 var(--radius-pill) var(--radius-pill) 0;
}

.seg-underweight {
    background: var(--color-underweight);
    opacity: 0.7;
}

.seg-normal {
    background: var(--color-normal);
    opacity: 0.7;
}

.seg-overweight {
    background: var(--color-overweight);
    opacity: 0.7;
}

.seg-obese {
    background: var(--color-obese);
    opacity: 0.7;
}

.scale-indicator {
    position: absolute;
    top: 50%;
    transform: translate(-50%, -50%);
    width: 18px;
    height: 18px;
    background: #fff;
    border-radius: 50%;
    border: 3px solid currentColor;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.5);
    transition: left 0.6s cubic-bezier(0.34, 1.4, 0.64, 1), border-color 0.3s ease;
    z-index: 2;
}

.scale-labels {
    display: flex;
    justify-content: space-between;
    font-size: 0.72rem;
    color: var(--color-text-muted);
    font-weight: 500;
    padding: 0 2px;
}

/* ===================================
   Weight Advice Box
=================================== */
.weight-advice-box {
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-md);
    padding: 18px 20px 14px;
    display: flex;
    flex-direction: column;
    gap: 14px;
    animation: resultReveal 0.5s cubic-bezier(0.34, 1.4, 0.64, 1) both 0.08s;
}

.advice-row {
    display: flex;
    align-items: stretch;
    gap: 0;
}

.advice-block {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    padding: 6px 10px;
    text-align: center;
}

.advice-divider-v {
    width: 1px;
    background: rgba(255, 255, 255, 0.1);
    margin: 4px 0;
    flex-shrink: 0;
}

.advice-label {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    line-height: 1.3;
}

.advice-sublabel {
    font-size: 0.68rem;
    text-transform: none;
    letter-spacing: 0;
    color: var(--color-text-muted);
    opacity: 0.7;
    margin-top: -2px;
}

.advice-value {
    font-size: 1.05rem;
    font-weight: 700;
    line-height: 1.2;
    margin-top: 4px;
    transition: color var(--transition-smooth);
}

/* Green when healthy range display */
.healthy-range-value {
    color: var(--color-normal);
}

/* Suggestion dynamic colors applied via JS class */
.suggestion-value.suggest-gain {
    color: var(--color-underweight);
}

.suggestion-value.suggest-lose {
    color: var(--color-obese);
}

.suggestion-value.suggest-normal {
    color: var(--color-normal);
}

/* Advice Message strip */
.advice-message {
    font-size: 0.82rem;
    font-weight: 500;
    text-align: center;
    padding: 9px 14px;
    border-radius: var(--radius-sm);
    line-height: 1.5;
    transition: background var(--transition-smooth), color var(--transition-smooth);
}

.advice-message.msg-gain {
    background: rgba(59, 130, 246, 0.12);
    color: #93c5fd;
    border: 1px solid rgba(59, 130, 246, 0.2);
}

.advice-message.msg-lose {
    background: rgba(239, 68, 68, 0.12);
    color: #fca5a5;
    border: 1px solid rgba(239, 68, 68, 0.2);
}

.advice-message.msg-normal {
    background: rgba(34, 197, 94, 0.12);
    color: #86efac;
    border: 1px solid rgba(34, 197, 94, 0.2);
}

/* ===================================
   Category Reference
=================================== */
.category-reference {
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: var(--radius-md);
    padding: 18px 20px;
}

.ref-title {
    font-size: 0.78rem;
    font-weight: 600;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.8px;
    margin-bottom: 12px;
}

.ref-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.ref-item {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 0.88rem;
}

.ref-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    flex-shrink: 0;
}

.ref-underweight .ref-dot {
    background: var(--color-underweight);
}

.ref-normal .ref-dot {
    background: var(--color-normal);
}

.ref-overweight .ref-dot {
    background: var(--color-overweight);
}

.ref-obese .ref-dot {
    background: var(--color-obese);
}

.ref-underweight .ref-text {
    color: var(--color-underweight);
    font-weight: 500;
}

.ref-normal .ref-text {
    color: var(--color-normal);
    font-weight: 500;
}

.ref-overweight .ref-text {
    color: var(--color-overweight);
    font-weight: 500;
}

.ref-obese .ref-text {
    color: var(--color-obese);
    font-weight: 500;
}

.ref-range {
    margin-left: auto;
    color: var(--color-text-muted);
    font-size: 0.8rem;
    font-weight: 400;
    font-variant-numeric: tabular-nums;
}

/* ===================================
   Highlight current category row
=================================== */
.ref-item.active-category {
    background: rgba(255, 255, 255, 0.05);
    border-radius: var(--radius-sm);
    padding: 6px 8px;
}

/* ===================================
   Reset Button
=================================== */
.reset-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    width: 100%;
    padding: 13px 24px;
    background: transparent;
    color: var(--color-text-secondary);
    font-size: 0.9rem;
    font-weight: 600;
    font-family: inherit;
    border: 1.5px solid rgba(255, 255, 255, 0.15);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: background var(--transition-smooth), color var(--transition-smooth),
        border-color var(--transition-smooth), transform var(--transition-smooth);
}

.reset-btn:hover {
    background: rgba(255, 255, 255, 0.07);
    color: var(--color-text-primary);
    border-color: rgba(255, 255, 255, 0.3);
    transform: translateY(-1px);
}

.reset-btn:active {
    transform: scale(0.98);
}

/* ===================================
   Responsive Design — Tablet
=================================== */
@media (max-width: 520px) {
    .card {
        padding: 30px 22px;
        border-radius: var(--radius-lg);
    }

    .card-title {
        font-size: 1.6rem;
    }

    .result-value {
        font-size: 3.8rem;
    }

    .icon-wrapper {
        width: 56px;
        height: 56px;
    }
}

/* ===================================
   Responsive Design — Mobile
=================================== */
@media (max-width: 360px) {
    .container {
        padding: 12px;
    }

    .card {
        padding: 24px 16px;
    }

    .card-title {
        font-size: 1.4rem;
    }

    .result-value {
        font-size: 3.2rem;
    }

    .input-field {
        padding: 12px 52px 12px 16px;
        font-size: 0.95rem;
    }
}

/* ===================================
   Utility: Scroll Padding for Body
=================================== */
body {
    padding-block: 24px;
}