:root {
    --bg-color: var(--tg-theme-bg-color, #f4f5f7);
    --text-color: var(--tg-theme-text-color, #222);
    --hint-color: var(--tg-theme-hint-color, #999);
    --button-color: var(--tg-theme-button-color, #3390ec);
    --button-text-color: var(--tg-theme-button-text-color, #ffffff);
    --card-bg: var(--tg-theme-secondary-bg-color, #ffffff);
    --accent-color: #10b981;
    --accent-glow: rgba(16, 185, 129, 0.3);
    --water-color: #3b82f6;
    --radius: 16px;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    -webkit-font-smoothing: antialiased;
    padding: 16px;
    padding-bottom: 32px;
}

h1, h2, h3 { margin-bottom: 8px; font-weight: 600; }
p { color: var(--hint-color); font-size: 14px; margin-bottom: 12px; }

/* Screens */
.screen {
    display: none;
    animation: fadeIn 0.3s ease;
}
.screen.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Loader */
#loading-screen {
    text-align: center;
    padding-top: 50px;
}
.loader {
    width: 40px;
    height: 40px;
    border: 4px solid var(--hint-color);
    border-top-color: var(--button-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 16px;
}
@keyframes spin { 100% { transform: rotate(360deg); } }

/* Cards */
.card {
    background-color: var(--card-bg);
    border-radius: var(--radius);
    padding: 20px;
    margin-bottom: 16px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.05);
    border: 1px solid rgba(0,0,0,0.02);
}

.highlight {
    color: var(--accent-color);
    font-weight: 700;
}

/* Forms */
.form-group {
    margin-bottom: 16px;
}
label {
    display: block;
    font-size: 14px;
    font-weight: 500;
    margin-bottom: 6px;
}
input[type="number"] {
    width: 100%;
    padding: 12px 16px;
    border-radius: 12px;
    border: 1px solid var(--hint-color);
    background: transparent;
    color: var(--text-color);
    font-size: 16px;
    transition: all 0.2s;
}
input[type="number"]:focus {
    outline: none;
    border-color: var(--button-color);
    box-shadow: 0 0 0 3px rgba(51, 144, 236, 0.2);
}

/* Gender Selector */
.gender-selector {
    display: flex;
    gap: 10px;
}
.btn-gender {
    flex: 1;
    padding: 12px;
    border-radius: 12px;
    border: 1px solid var(--hint-color);
    background: transparent;
    color: var(--text-color);
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}
.btn-gender.active {
    background-color: var(--button-color);
    color: var(--button-text-color);
    border-color: var(--button-color);
}

/* Buttons */
.btn {
    display: block;
    width: 100%;
    padding: 14px;
    border: none;
    border-radius: 12px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.1s, opacity 0.2s;
}
.btn:active { transform: scale(0.98); }
.btn-primary {
    background-color: var(--button-color);
    color: var(--button-text-color);
    box-shadow: 0 4px 15px rgba(51, 144, 236, 0.3);
}
.btn-outline {
    background-color: transparent;
    border: 1px solid var(--hint-color);
    color: var(--text-color);
}
.btn-small {
    padding: 8px 12px;
    font-size: 14px;
    margin-top: 10px;
    background-color: var(--bg-color);
    color: var(--text-color);
}
.btn-water {
    background-color: var(--water-color);
    color: #fff;
    box-shadow: 0 4px 15px rgba(59, 130, 246, 0.3);
}

.mt-4 { margin-top: 24px; }

/* Dashboard Metrics */
.dashboard-header { margin-bottom: 24px; }
.metrics-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}
.metric-card {
    padding: 16px;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}
.metric-icon {
    font-size: 28px;
    margin-bottom: 8px;
}
.metric-value {
    font-size: 18px;
    font-weight: 700;
    color: var(--text-color);
    margin: 0;
}

/* Water Tracker & Treadmill */
.water-header, .treadmill-header, .chart-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}
.water-header h3, .treadmill-header h3, .chart-header h3 { margin: 0; font-size: 16px; }

.progress-bar-container {
    height: 12px;
    background-color: var(--bg-color);
    border-radius: 6px;
    overflow: hidden;
    margin-bottom: 16px;
}
.progress-bar {
    height: 100%;
    background-color: var(--water-color);
    width: 0%;
    transition: width 0.5s ease-out;
}

.chart-container {
    position: relative;
    height: 200px;
    width: 100%;
}

.btn-treadmill {
    background-color: var(--accent-color);
    color: #fff;
    box-shadow: 0 4px 15px rgba(16, 185, 129, 0.3);
}

/* Modals */
.modal-overlay {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0,0,0,0.5);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.2s;
}
.modal-overlay.active {
    opacity: 1;
    pointer-events: auto;
}
.modal {
    background: var(--card-bg);
    width: 90%;
    max-width: 400px;
    padding: 24px;
    border-radius: var(--radius);
    transform: translateY(20px);
    transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}
.modal-overlay.active .modal {
    transform: translateY(0);
}
.modal-actions {
    display: flex;
    gap: 12px;
    margin-top: 20px;
}