:root {
    --bg-color: #f5f5f5;
    --container-bg: white;
    --text-color: #333;
    --section-bg: #f8f9fa;
    --border-color: #ddd;
    --input-bg: white;
    --input-border: #ddd;
    --input-focus-border: #3498db;
    --input-focus-shadow: rgba(52, 152, 219, 0.2);
    --heading-color: #2c3e50;
    --button-bg: #3498db;
    --button-hover: #2980b9;
    --clear-button-bg: #dc3545;
    --clear-button-hover: #c82333;
    --placeholder-color: #666;
}

[data-theme="dark"] {
    --bg-color: #1a1a1a;
    --container-bg: #2d2d2d;
    --text-color: #e0e0e0;
    --section-bg: #363636;
    --border-color: #404040;
    --input-bg: #404040;
    --input-border: #505050;
    --input-focus-border: #3498db;
    --input-focus-shadow: rgba(52, 152, 219, 0.3);
    --heading-color: #e0e0e0;
    --button-bg: #3498db;
    --button-hover: #2980b9;
    --clear-button-bg: #dc3545;
    --clear-button-hover: #c82333;
    --placeholder-color: #999;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    background-color: var(--bg-color);
    color: var(--text-color);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 2rem;
    background-color: var(--container-bg);
    border-radius: 10px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    flex: 1;
    transition: background-color 0.3s ease;
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.theme-toggle {
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-color);
    transition: background-color 0.3s ease;
}

.theme-toggle:hover {
    background-color: var(--section-bg);
}

.theme-toggle svg {
    width: 24px;
    height: 24px;
}

.sun-icon {
    display: none;
}

.moon-icon {
    display: block;
}

[data-theme="dark"] .sun-icon {
    display: block;
}

[data-theme="dark"] .moon-icon {
    display: none;
}

h1 {
    text-align: left;
    color: var(--heading-color);
    margin: 0;
    transition: color 0.3s ease;
}

h2 {
    color: var(--heading-color);
    font-size: 1.5rem;
    margin-bottom: 1rem;
    transition: color 0.3s ease;
}

.form-section,
.main-section {
    margin-bottom: 2rem;
    padding: 1.5rem;
    background-color: var(--section-bg);
    border-radius: 8px;
    position: relative;
    transition: background-color 0.3s ease;
}

.form-section h2,
.main-section h2 {
    margin-top: 0;
    margin-bottom: 1rem;
    color: var(--heading-color);
    font-size: 1.5rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--heading-color);
    transition: color 0.3s ease;
}

input[type="text"],
input[type="email"],
input[type="date"],
input[type="time"],
textarea,
select {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid var(--input-border);
    border-radius: 4px;
    font-size: 1rem;
    transition: all 0.3s ease;
    background-color: var(--input-bg);
    color: var(--text-color);
}

input::placeholder {
    color: var(--placeholder-color);
}

input[type="date"]::-webkit-calendar-picker-indicator {
    filter: invert(var(--calendar-invert));
}

[data-theme="dark"] input[type="date"]::-webkit-calendar-picker-indicator {
    filter: invert(1);
}

select {
    appearance: none;
    background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
    background-repeat: no-repeat;
    background-position: right 0.7rem center;
    background-size: 1em;
    padding-right: 2.5rem;
}

select option {
    background-color: var(--input-bg);
    color: var(--text-color);
}

input:focus,
textarea:focus,
select:focus {
    outline: none;
    border-color: var(--input-focus-border);
    box-shadow: 0 0 0 2px var(--input-focus-shadow);
}

textarea {
    resize: vertical;
    min-height: 100px;
}

.submit-btn {
    display: block;
    width: 100%;
    padding: 1rem;
    background-color: #3498db;
    color: white;
    border: none;
    border-radius: 4px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.submit-btn:hover {
    background-color: #2980b9;
}

.output-container {
    position: relative;
}

#formattedOutput {
    font-family: monospace;
    background-color: var(--input-bg);
    border: 1px solid var(--input-border);
    padding: 1rem;
    min-height: 200px;
    white-space: pre-wrap;
    word-wrap: break-word;
    color: var(--text-color);
    transition: all 0.3s ease;
}

.copy-btn {
    position: absolute;
    top: 0.5rem;
    right: 0.5rem;
    padding: 0.5rem;
    background-color: var(--button-bg);
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
}

.copy-btn:hover {
    background-color: var(--button-hover);
    transform: scale(1.05);
}

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

.copy-btn svg {
    width: 16px;
    height: 16px;
}

.ad-container {
    width: 100%;
    background-color: #f8f9fa;
    padding: 1rem;
    text-align: center;
    border-top: 1px solid #ddd;
}

.ad-placeholder {
    max-width: 728px;
    margin: 0 auto;
    padding: 1rem;
    background-color: #e9ecef;
    border-radius: 4px;
    color: #6c757d;
}

.flight-type-select {
    width: 100%;
    padding: 8px;
    border: 1px solid var(--input-border);
    border-radius: 4px;
    font-size: 16px;
    background-color: var(--input-bg);
    color: var(--text-color);
    font-family: inherit;
    appearance: none;
    background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
    background-repeat: no-repeat;
    background-position: right 0.7rem center;
    background-size: 1em;
    padding-right: 2.5rem;
    transition: all 0.3s ease;
}

.flight-type-select:focus {
    outline: none;
    border-color: var(--input-focus-border);
    box-shadow: 0 0 0 2px var(--input-focus-shadow);
}

.flight-type-select option {
    background-color: var(--input-bg);
    color: var(--text-color);
    padding: 8px;
}

.clear-btn {
    padding: 8px;
    background-color: var(--clear-button-bg);
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
    position: absolute;
    top: 1.5rem;
    right: 1.5rem;
}

.clear-btn:hover {
    background-color: var(--clear-button-hover);
    transform: scale(1.05);
}

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

.clear-btn svg {
    width: 16px;
    height: 16px;
}

/* Desktop Layout */
@media (min-width: 1024px) {
    .container {
        padding: 2rem;
    }

    #gcrForm {
        display: grid;
        grid-template-columns: 1fr 1fr;
        gap: 2rem;
    }

    /* Main section */
    .main-section {
        grid-column: 1;
        grid-row: 1;
        display: grid;
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
        background-color: var(--section-bg);
        padding: 1.5rem;
        border-radius: 8px;
        position: relative;
    }

    .main-section h2 {
        grid-column: 1 / -1;
        margin-bottom: 1rem;
    }

    /* Arrival section */
    .arrival-section {
        grid-column: 2;
        grid-row: 1;
        margin-bottom: 0;
    }

    /* Output section */
    .output-section {
        grid-column: 1;
        grid-row: 2;
        margin-bottom: 0;
    }

    /* Departure section */
    .departure-section {
        grid-column: 2;
        grid-row: 2;
        margin-bottom: 0;
    }

    /* Adjust form group spacing for desktop */
    .form-group {
        margin-bottom: 1rem;
    }

    /* Make the output section taller on desktop */
    #formattedOutput {
        min-height: 300px;
    }
}

@media (max-width: 768px) {
    .container {
        margin: 1rem;
        padding: 1rem;
    }
    
    .form-section {
        padding: 1rem;
    }
}