:root {
    --primary-color: #FF5722; /* Vibrant Orange */
    --secondary-color: #4CAF50; /* Energetic Green */
    --accent-color: #2196F3; /* Bright Blue */
    --bg-color: #f4f7f6;
    --card-bg: #ffffff;
    --text-color: #333333;
    --text-muted: #757575;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, sans-serif;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
}

.container {
    width: 100%;
    max-width: 400px;
    background: var(--card-bg);
    border-radius: 24px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    overflow: hidden;
    padding: 30px 20px;
}

header {
    text-align: center;
    margin-bottom: 30px;
}

header h1 {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 8px;
    text-transform: uppercase;
    letter-spacing: -1px;
}

header p {
    font-size: 0.9rem;
    color: var(--text-muted);
}

.input-card {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

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

.input-group label {
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--text-color);
}

.input-group input {
    padding: 15px;
    border: 2px solid #eee;
    border-radius: 12px;
    font-size: 1.1rem;
    outline: none;
    transition: border-color 0.3s;
}

.input-group input:focus {
    border-color: var(--primary-color);
}

button {
    padding: 16px;
    border: none;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 700;
    cursor: pointer;
    transition: transform 0.2s, background-color 0.3s;
}

#calculate-btn {
    background-color: var(--primary-color);
    color: white;
    margin-top: 10px;
    box-shadow: 0 4px 15px rgba(255, 87, 34, 0.3);
}

#calculate-btn:active {
    transform: scale(0.98);
}

#result-section {
    margin-top: 30px;
    animation: slideUp 0.5s ease-out;
}

.hidden {
    display: none;
}

@keyframes slideUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.result-card {
    text-align: center;
    background: #f9f9f9;
    padding: 20px;
    border-radius: 16px;
    margin-bottom: 25px;
}

.result-card h2 {
    font-size: 1rem;
    color: var(--text-muted);
    margin-bottom: 10px;
}

.bmi-score {
    font-size: 3.5rem;
    font-weight: 800;
    color: var(--primary-color);
    line-height: 1;
    margin-bottom: 20px;
}

.standards-comparison {
    display: flex;
    justify-content: center;
    align-items: stretch;
    gap: 15px;
    margin-bottom: 20px;
    padding: 15px;
    background: white;
    border-radius: 12px;
}

.standard-item {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.standard-label {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-muted);
}

.category-name {
    font-size: 1.1rem;
    font-weight: 800;
}

.range-info {
    font-size: 0.7rem;
    color: #999;
}

.standard-divider {
    width: 1px;
    background-color: #eee;
}

.bmi-desc {
    font-size: 0.95rem;
    line-height: 1.5;
    color: var(--text-muted);
}

/* Gauge Styles */
.gauge-container {
    margin-bottom: 30px;
    padding: 0 10px;
}

.gauge-bar {
    position: relative;
    height: 12px;
    background: #eee;
    border-radius: 6px;
    margin-bottom: 10px;
}

.segments {
    display: flex;
    height: 100%;
    border-radius: 6px;
    overflow: hidden;
}

.segment { height: 100%; }
.underweight { flex: 18.5; background-color: #FFC107; }
.normal { flex: 6.5; background-color: #4CAF50; }
.overweight { flex: 5; background-color: #FF9800; }
.obese { flex: 10; background-color: #F44336; }

.pointer {
    position: absolute;
    top: -8px;
    width: 4px;
    height: 28px;
    background: #333;
    border-radius: 2px;
    transition: left 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    z-index: 2;
}

.gauge-labels {
    display: flex;
    justify-content: space-between;
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 500;
}

.motivational-quote {
    text-align: center;
    font-style: italic;
    color: var(--accent-color);
    margin-bottom: 25px;
    padding: 0 10px;
}

#reset-btn {
    width: 100%;
    background-color: #eee;
    color: var(--text-color);
}

footer {
    text-align: center;
    margin-top: 30px;
    font-size: 0.8rem;
    color: var(--text-muted);
}