:root {
    --primary-color: #1E90FF;
    --secondary-color: #4169E1;
    --accent-color: #E0F2FF;
    --text-color: #2C3E50;
    --bg-color: #F8FCFF;
    --card-bg: #FFFFFF;
    --border-color: #B8D4E8;
    --font-main: 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
}

body {
    font-family: var(--font-main);
    background: linear-gradient(135deg, #F8FCFF 0%, #E8F4FC 100%);
    color: var(--text-color);
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    line-height: 1.7;
}

header {
    background: linear-gradient(90deg, #FFFFFF 0%, #F0F8FF 100%);
    padding: 1.5rem 2rem;
    box-shadow: 0 3px 12px rgba(30, 144, 255, 0.08);
    display: flex;
    justify-content: center;
    align-items: center;
    border-bottom: 2px solid var(--accent-color);
}

.logo {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

.logo a {
    color: var(--primary-color);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.logo img {
    height: 55px;
    width: auto;
}

main {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 3rem 1.5rem;
    max-width: 900px;
    margin: 0 auto;
    width: 100%;
    box-sizing: border-box;
}

.survey-container {
    background-color: var(--card-bg);
    padding: 2.5rem;
    border-radius: 16px;
    box-shadow: 0 10px 30px rgba(30, 144, 255, 0.12);
    width: 100%;
    box-sizing: border-box;
    border: 1px solid var(--border-color);
}

h1 {
    color: var(--primary-color);
    font-size: 2.2rem;
    margin-bottom: 1rem;
    font-weight: 700;
}

h2 {
    color: var(--secondary-color);
    font-size: 1.8rem;
    margin-bottom: 0.8rem;
    font-weight: 600;
}

h3 {
    color: var(--primary-color);
    font-size: 1.4rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

p {
    line-height: 1.8;
    color: var(--text-color);
    font-size: 1.05rem;
}

.btn {
    display: inline-block;
    padding: 14px 32px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    text-decoration: none;
    border-radius: 8px;
    font-weight: 600;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
    font-size: 1.05rem;
    box-shadow: 0 4px 12px rgba(30, 144, 255, 0.25);
    text-align: center;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(30, 144, 255, 0.35);
}

.btn-secondary {
    background: linear-gradient(135deg, #E8F4FC 0%, #D0E8F7 100%);
    color: var(--secondary-color);
    box-shadow: 0 4px 12px rgba(65, 105, 225, 0.15);
}

.btn-secondary:hover {
    background: linear-gradient(135deg, #D0E8F7 0%, #B8DCF0 100%);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(65, 105, 225, 0.25);
}

/* Unique Architecture: Centered stacked buttons */
.navigation-buttons {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    margin-top: 2.5rem;
}

.navigation-buttons .btn {
    width: 100%;
    max-width: 300px;
}

/* Desktop: side by side centered */
@media (min-width: 601px) {
    .navigation-buttons {
        flex-direction: row;
        justify-content: center;
        gap: 1.5rem;
    }
    .navigation-buttons .btn {
        width: auto;
        min-width: 180px;
    }
}

/* Progress Bar */
.progress-container {
    width: 100%;
    background-color: #D0E8F7;
    border-radius: 12px;
    margin-bottom: 2rem;
    height: 12px;
    overflow: hidden;
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.08);
}

.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    width: 0%;
    transition: width 0.6s ease;
    border-radius: 12px;
}

footer {
    background: linear-gradient(90deg, #FFFFFF 0%, #F0F8FF 100%);
    padding: 2.5rem 2rem;
    text-align: center;
    border-top: 2px solid var(--accent-color);
    font-size: 0.95rem;
    color: var(--text-color);
}

footer a {
    color: var(--primary-color);
    text-decoration: none;
    margin: 0 12px;
    font-weight: 500;
    transition: color 0.2s ease;
}

footer a:hover {
    color: var(--secondary-color);
    text-decoration: underline;
}

.options-group {
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
    margin: 2rem 0;
}

.option-label {
    display: flex;
    align-items: center;
    padding: 1.2rem 1.5rem;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    background-color: #FAFCFF;
    font-size: 1.05rem;
}

.option-label:hover {
    border-color: var(--primary-color);
    background-color: var(--accent-color);
    transform: translateX(5px);
    box-shadow: 0 4px 12px rgba(30, 144, 255, 0.15);
}

.option-label input {
    margin-right: 1.2rem;
    width: 20px;
    height: 20px;
    cursor: pointer;
}

/* Mobile responsiveness */
@media (max-width: 600px) {
    h1 {
        font-size: 1.8rem;
    }
    h2 {
        font-size: 1.5rem;
    }
    h3 {
        font-size: 1.2rem;
    }
    .survey-container {
        padding: 1.5rem;
    }
    main {
        padding: 2rem 1rem;
    }
}