:root {
    --bg-dark: #121212;
    --bg-card: #1E1E1E;
    --bg-input: #2D2D2D;
    --accent-primary: #FFB703; /* Yellow */
    --accent-secondary: #FB8500; /* Orange */
    --text-primary: #FFFFFF;
    --text-secondary: #A0A0A0;
    --font-ui: 'Inter', sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
    --border-radius: 16px;
    --transition-speed: 0.3s;
}

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

body {
    background-color: var(--bg-dark);
    color: var(--text-primary);
    font-family: var(--font-ui);
    -webkit-font-smoothing: antialiased;
    line-height: 1.5;
    padding-bottom: 40px;
}

/* Header */
.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 24px 20px;
    background: linear-gradient(180deg, rgba(30,30,30,0.8) 0%, rgba(18,18,18,0) 100%);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
}

.app-header h1 {
    font-size: 1.5rem;
    font-weight: 800;
    letter-spacing: -0.5px;
}

.app-header h1 span {
    color: var(--accent-primary);
    /* Gradient text */
    background: linear-gradient(90deg, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.subtitle {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-top: 4px;
}

.status-indicator {
    font-size: 0.75rem;
    font-weight: 600;
    padding: 4px 8px;
    border-radius: 12px;
    background: var(--bg-card);
    display: flex;
    align-items: center;
    gap: 6px;
}

.status-indicator span::before {
    content: '';
    display: inline-block;
    width: 8px;
    height: 8px;
    border-radius: 50%;
    margin-right: 6px;
}

.status-indicator .online::before {
    background-color: #4CAF50;
    box-shadow: 0 0 8px #4CAF50;
}

.status-indicator .offline::before {
    background-color: var(--accent-secondary);
    box-shadow: 0 0 8px var(--accent-secondary);
}

/* Grid Layout */
.calculators-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
    padding: 0 20px;
    max-width: 1200px;
    margin: 0 auto;
}

@media (min-width: 768px) {
    .calculators-grid {
        grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    }
}

/* Card Styles */
.calc-card {
    background-color: var(--bg-card);
    border-radius: var(--border-radius);
    padding: 24px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.3);
    border: 1px solid rgba(255,255,255,0.05);
    transition: transform var(--transition-speed) ease, box-shadow var(--transition-speed) ease;
    display: flex;
    flex-direction: column;
    gap: 20px;
    overflow: hidden;
    position: relative;
}

.calc-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--accent-primary), var(--accent-secondary));
    opacity: 0.7;
}

.calc-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 15px 40px rgba(0,0,0,0.5);
}

.card-header h2 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 4px;
}

.card-header p {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

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

.input-group label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.input-wrapper {
    display: flex;
    align-items: center;
    background-color: var(--bg-input);
    border-radius: 8px;
    border: 1px solid transparent;
    transition: border-color var(--transition-speed) ease;
}

.input-wrapper:focus-within {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 2px rgba(255, 183, 3, 0.2);
}

.input-wrapper input {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-family: var(--font-mono);
    font-size: 1.1rem;
    padding: 12px 16px;
    min-width: 0;
    outline: none;
}

.input-suffix {
    padding-right: 16px;
    color: var(--accent-secondary);
    font-weight: 600;
    font-size: 0.9rem;
    user-select: none;
}

/* Results */
.result-display {
    background-color: rgba(0,0,0,0.3);
    border-radius: 12px;
    padding: 16px;
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    margin-top: auto;
    border-left: 4px solid var(--accent-primary);
}

.result-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    font-weight: 800;
    letter-spacing: 1px;
    margin-bottom: 4px;
}

.result-value {
    font-family: var(--font-mono);
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--accent-primary);
    word-break: break-all;
    display: flex;
    align-items: baseline;
    gap: 4px;
}

.result-unit {
    font-size: 1rem;
    color: var(--text-secondary);
    font-weight: 600;
}

.result-tag {
    display: inline-block;
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.7rem;
    font-weight: 800;
    text-transform: uppercase;
    margin-top: 8px;
}

.tag-delay {
    background-color: rgba(220, 53, 69, 0.2);
    color: #ff4d4d;
}

.tag-advance {
    background-color: rgba(76, 175, 80, 0.2);
    color: #4CAF50;
}