:root {
    --bg-color: #0f172a;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-color: #f59e0b; /* Amber 500 */
    --accent-hover: #d97706;

    --glass-bg: rgba(30, 41, 59, 0.7);
    --glass-border: rgba(255, 255, 255, 0.08);
    --glass-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
    --glass-blur: blur(12px);

    --card-radius: 16px;
    --input-radius: 8px;

    --font-family: "Inter", system-ui, -apple-system, sans-serif;
    --transition-speed: 0.3s;
}

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

body {
    font-family: var(--font-family);
    background-color: var(--bg-color);
    background-image:
        radial-gradient(at 0% 0%, rgba(79, 70, 229, 0.15) 0px, transparent 50%),
        radial-gradient(
            at 100% 0%,
            rgba(245, 158, 11, 0.1) 0px,
            transparent 50%
        ),
        radial-gradient(
            at 100% 100%,
            rgba(16, 185, 129, 0.15) 0px,
            transparent 50%
        );
    background-attachment: fixed;
    background-size: cover;
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
    padding-bottom: 2rem;
}

/* Optional background image overlay if provided via JS or user edit */
.background-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    pointer-events: none;
    /* Unsplash source for a hiking background */
    background: url("https://images.unsplash.com/photo-1551632811-561732d1e306?q=80&w=2070&auto=format&fit=crop")
        no-repeat center center/cover;
    opacity: 0.4;
    filter: blur(2px);
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* Header Styles */
header {
    padding: 2rem 0 3rem;
    text-align: center;
}

.header-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
}

.logo {
    display: flex;
    align-items: center;
    gap: 1rem;
    font-size: 2.5rem;
    font-weight: 700;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

.logo i {
    color: var(--accent-color);
}

header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
    font-weight: 300;
    background: rgba(0, 0, 0, 0.3);
    padding: 4px 12px;
    border-radius: 20px;
    backdrop-filter: blur(4px);
}

/* Grid Layout */
.converter-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: 2rem;
}

/* Card Styling - Glassmorphism */
.card {
    background: var(--glass-bg);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border: 1px solid var(--glass-border);
    border-radius: var(--card-radius);
    box-shadow: var(--glass-shadow);
    padding: 1.5rem;
    transition:
        transform var(--transition-speed),
        border-color var(--transition-speed);
}

.card:hover {
    transform: translateY(-4px);
    border-color: rgba(255, 255, 255, 0.2);
}

.card-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1.5rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    padding-bottom: 1rem;
}

.card-icon {
    width: 40px;
    height: 40px;
    background: rgba(245, 158, 11, 0.15);
    color: var(--accent-color);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
}

.card-header h2 {
    font-size: 1.25rem;
    font-weight: 600;
}

/* Form Elements */
.card-body {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.conversion-row {
    display: flex;
    align-items: flex-end; /* Align inputs and icon */
    justify-content: space-between;
    gap: 0.5rem;
}

.input-group {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.input-group label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.input-group.full-width {
    width: 100%;
}

input[type="number"] {
    width: 100%;
    background: rgba(0, 0, 0, 0.2);
    border: 1px solid var(--glass-border);
    border-radius: var(--input-radius);
    padding: 0.75rem 1rem;
    color: var(--text-primary);
    font-size: 1.1rem;
    font-family: var(--font-family);
    transition: all 0.2s ease;
    /* Remove number spinners for cleaner look */
    -moz-appearance: textfield;
}

input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

input[type="number"]:focus {
    outline: none;
    border-color: var(--accent-color);
    background: rgba(0, 0, 0, 0.4);
    box-shadow: 0 0 0 3px rgba(245, 158, 11, 0.15);
}

.icon-exchange {
    color: var(--text-secondary);
    padding-bottom: 0.85rem; /* Align visually with inputs */
    font-size: 0.9rem;
    opacity: 0.6;
}

.quick-fact {
    text-align: center;
    font-size: 0.85rem;
    color: var(--text-secondary);
    background: rgba(255, 255, 255, 0.03);
    padding: 0.5rem;
    border-radius: 8px;
    margin-top: 0.5rem;
    border: 1px solid rgba(255, 255, 255, 0.02);
}

/* Pace Converter Specifics */
.pace-row {
    flex-direction: column;
    align-items: stretch;
    gap: 1.5rem;
}

.pace-row .icon-exchange {
    align-self: center;
    transform: rotate(90deg);
    padding-bottom: 0;
}

.time-input-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.time-field {
    text-align: center;
}

.time-separator {
    font-weight: bold;
    color: var(--text-secondary);
}

/* Footer */
footer {
    text-align: center;
    padding: 3rem 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Responsive adjustments */
@media (max-width: 640px) {
    .header-content {
        padding: 0 1rem;
    }

    .logo {
        font-size: 2rem;
    }

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

    .conversion-row {
        gap: 0.25rem;
    }

    input[type="number"] {
        padding: 0.6rem 0.5rem;
        font-size: 1rem;
    }
}

/* Utility for hiding scrollbar if needed */
html {
    scrollbar-width: thin;
    scrollbar-color: var(--glass-border) var(--bg-color);
}

/* =========================================
   New UI Elements: Sliders, Grids, Dials
   ========================================= */

/* Range Sliders */
.slider-container {
    width: 100%;
    padding: 0 0.5rem;
    margin-bottom: 0.5rem;
}

input[type="range"] {
    width: 100%;
    background: transparent;
    -webkit-appearance: none;
    cursor: pointer;
}

input[type="range"]:focus {
    outline: none;
}

/* Slider Track */
input[type="range"]::-webkit-slider-runnable-track {
    width: 100%;
    height: 6px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 3px;
    border: 1px solid var(--glass-border);
}

input[type="range"]::-moz-range-track {
    width: 100%;
    height: 6px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 3px;
    border: 1px solid var(--glass-border);
}

/* Slider Thumb */
input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    height: 20px;
    width: 20px;
    border-radius: 50%;
    background: var(--accent-color);
    margin-top: -8px; /* Centers thumb on track */
    box-shadow: 0 0 10px rgba(245, 158, 11, 0.5);
    transition: transform 0.1s;
}

input[type="range"]::-moz-range-thumb {
    height: 20px;
    width: 20px;
    border: none;
    border-radius: 50%;
    background: var(--accent-color);
    box-shadow: 0 0 10px rgba(245, 158, 11, 0.5);
    transition: transform 0.1s;
}

input[type="range"]:active::-webkit-slider-thumb {
    transform: scale(1.2);
    background: var(--accent-hover);
}

input[type="range"]:active::-moz-range-thumb {
    transform: scale(1.2);
    background: var(--accent-hover);
}

/* Quick Action Grid (Chips) */
.quick-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.5rem;
    margin-top: 0.5rem;
}

.chip {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    color: var(--text-secondary);
    padding: 0.5rem;
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.85rem;
    font-weight: 600;
    transition: all 0.2s ease;
    text-align: center;
}

.chip:hover {
    background: rgba(255, 255, 255, 0.15);
    color: var(--text-primary);
    border-color: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

.chip:active {
    transform: translateY(0);
    background: var(--accent-color);
    color: #fff;
    border-color: var(--accent-color);
}

/* Circular Dial (Knob) */
.dial-wrapper {
    display: flex;
    justify-content: center;
    margin-bottom: 1rem;
}

.dial-container {
    width: 120px;
    height: 120px;
    position: relative;
    border-radius: 50%;
    background: rgba(0, 0, 0, 0.2);
    border: 2px solid var(--glass-border);
    box-shadow: inset 0 0 20px rgba(0, 0, 0, 0.5);
    cursor: grab;
    touch-action: none; /* Prevent scrolling while using dial */
}

.dial-container:active {
    cursor: grabbing;
}

.dial-track {
    position: absolute;
    top: 10px;
    left: 10px;
    right: 10px;
    bottom: 10px;
    border-radius: 50%;
    border: 4px solid rgba(255, 255, 255, 0.05);
    border-top-color: var(--accent-color);
    transform: rotate(-135deg); /* Start position visual */
}

.dial-knob {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border-radius: 50%;
    /* Indicator dot */
}

.dial-knob::after {
    content: "";
    position: absolute;
    top: 10px;
    left: 50%;
    width: 8px;
    height: 8px;
    background: var(--accent-color);
    border-radius: 50%;
    transform: translateX(-50%);
    box-shadow: 0 0 8px var(--accent-color);
}

.dial-center {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    pointer-events: none; /* Let clicks pass to container */
    font-feature-settings: "tnum";
    font-variant-numeric: tabular-nums;
}

.dial-center span {
    display: block;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}