:root {
    --bg-color: #0f172a;
    --card-bg: #1e293b;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-color: #3b82f6;
    --accent-hover: #2563eb;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --neutral-color: #64748b;
    --nav-height: 64px;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.5;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: var(--nav-height);
    padding: 0 2rem;
    background-color: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: -0.025em;
    background: linear-gradient(to right, #60a5fa, #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.run-btn {
    background-color: var(--accent-color);
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 0.375rem;
    font-weight: 500;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
}

.run-btn:hover {
    background-color: var(--accent-hover);
}

.run-btn:active {
    transform: scale(0.95);
}

.run-btn:disabled {
    background-color: var(--neutral-color);
    cursor: not-allowed;
    opacity: 0.7;
}

.container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 2rem;
    padding-top: calc(var(--nav-height) + 2rem);
}

.status-card {
    background-color: var(--card-bg);
    padding: 3rem;
    border-radius: 1rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    text-align: center;
    width: 100%;
    max-width: 500px;
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.status-card h1 {
    font-size: 1.5rem;
    margin-bottom: 2rem;
    color: var(--text-secondary);
}

.result-box {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
    min-height: 4.5rem; /* prevent layout shift */
    display: flex;
    align-items: center;
    justify-content: center;
}

.placeholder {
    font-size: 1rem;
    color: var(--text-secondary);
    font-weight: 400;
}

.result-long {
    color: var(--success-color);
    text-shadow: 0 0 20px rgba(16, 185, 129, 0.3);
}

.result-short {
    color: var(--danger-color);
    text-shadow: 0 0 20px rgba(239, 68, 68, 0.3);
}

.result-flat {
    color: var(--neutral-color);
}

.date-box {
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-top: 1rem;
}

/* Loading animation */
.loader {
    border: 3px solid rgba(255, 255, 255, 0.1);
    border-top: 3px solid var(--accent-color);
    border-radius: 50%;
    width: 24px;
    height: 24px;
    animation: spin 1s linear infinite;
    display: inline-block;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}