header {
    background-color: #333333;
    color: white;
    width: 100%;
    height: 120px;
    padding: 6px;
    font-size: medium;
    display: flex;
    align-items: center;
    justify-content: center;
}

.controls-row {
    display: flex;
    gap: 24px;
    justify-content: start;
    align-items: flex-start;
    padding: 32px;
}

.controls-row label {
    display: flex;
    flex-direction: column;
    gap: 6px;
    width: min(20rem, 100%);
    padding: 0.5rem;
}

.controls-row input,
.controls-row select {
    min-width: 15rem;
}

@media (max-width: 640px) {
    .controls-row {
        flex-direction: column;
        gap: 8px;
        padding: 10px;
    }
    .controls-row input,
    .controls-row select {
        width: 100%;
        min-width: 0;
    }
}

/* Form controls: text inputs, number inputs and selects */
.filter-fields {
    font-family: inherit;
    font-size: 16px;
    padding: 8px 10px;
    border: 1px solid #ccc;
    border-radius: 6px;
    background: #fff;
    color: #222;
    outline: none;
    transition:
        border-color 150ms ease,
        box-shadow 150ms ease;
    box-sizing: border-box;
}

.filter-fields:focus {
    border-color: #1e90ff;
    box-shadow: 0 0 0 4px rgba(30, 144, 255, 0.12);
}

.filter-fields.invalid {
    border-color: #dc3545;
    box-shadow: 0 0 0 4px rgba(220, 53, 69, 0.16);
}

.input-error-message {
    display: none;
    color: #842029;
    font-size: 0.9rem;
    margin-top: 6px;
}

.input-error-message.visible {
    display: block;
}

.filter-fields {
    appearance: none;
    -webkit-appearance: none;
    -moz-appearance: none;
    padding-right: 30px; /* make room for native dropdown arrow */
}

.population-max {
    font-size: 12px;
    color: #666;
    margin-top: 4px;
}

#country-cards-container {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    grid-auto-rows: minmax(260px, auto);
    gap: 20px;
    padding: 24px;
}

.country-card {
    background: #e0e0e0;
    border-radius: 6px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
    overflow: hidden;
    display: flex;
    grid-template-columns: 1fr 1fr 1fr 1fr;
    flex-direction: column;
    justify-content: flex-start;
    gap: 12px;
    padding: 20px 20px 32px;
}

.country-card img {
    width: 200px;
    height: 105px;
    object-fit: cover;
}

.country-card h2 {
    margin: 0;
    font-size: 1.1rem;
}

.country-card p {
    margin: 0;
    line-height: 4.32px;
    color: #333;
}

.show-more {
    display: block;
    margin: 10px;
    padding: 10px 20px;
    font-size: 16px;
    background-color: #333333;
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    transition: background-color 150ms ease;
}

.error-message {
    display: inline-block;
    width: 100%;
    height: 15%;
    padding: 18px 22px;
    background-color: #f8d7da;
    color: #842029;
    border: 1px solid #f5c2c7;
    border-radius: 12px;
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.08);
    font-size: 1rem;
    line-height: 1.5;
}

.country-details {
    display: flex;
    flex-direction: column;
    width: 100%;
    grid-template-columns: 1fr;
    align-items: center;
}

.country-details img {
    width: 380px;
    height:auto;
    box-shadow: 0 0 20px 24px rgba(0, 0, 0, 0.08);
    object-fit: cover;
}

.details-list {
   padding:0;
   line-height: 4.32px;
}

/* Container for centering the spinner in grid or flex layouts */
.spinner-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 3rem 1rem;
    grid-column: 1 / -1; /* Spans across all grid columns if using CSS grid */
    width: 100%;
}

/* Animated CSS Spinner */
.spinner {
    width: 48px;
    height: 48px;
    border: 4px solid #e2e8f0; /* Light grey base border */
    border-top-color: #06b6d4; /* Cyan accent color matching the visual diagram */
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

/* Continuous 360-degree rotation keyframes */
@keyframes spin {
    0% {
        transform: rotate(0deg);
    }
    100% {
        transform: rotate(360deg);
    }
}

/* Small responsive tweak */
@media (max-width: 480px) {
    .filter-fields {
        font-size: 14px;
        padding: 6px 8px;
    }
}

@media (max-width: 1024px) {
    #country-cards-container {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 620px) {
    #country-cards-container {
        grid-template-columns: 1fr;
    }
}