:root {
    --bg-color: #0f172a;
    --text-color: #f8fafc;
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --accent-color: #8b5cf6;
    --error-color: #ef4444;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --input-bg: #1e293b;
    --input-border: #334155;
    --radius: 8px;
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-image: linear-gradient(rgba(15, 23, 42, 0.7), rgba(15, 23, 42, 0.7)), url('../images/building.jpg');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    padding: 2rem 1rem;
}

.container {
    width: 100%;
    max-width: 640px;
    padding: 2.5rem;
    text-align: center;
    position: relative;
    z-index: 10;
    background-color: rgba(15, 23, 42, 0.85);
    border-radius: var(--radius);
    backdrop-filter: blur(5px);
    box-shadow: var(--shadow);
}

header h1 {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 1rem;
    color: white;
}

header p {
    font-size: 1.2rem;
    color: #cbd5e1;
    margin-bottom: 2.5rem;
}

.register-form {
    margin-bottom: 2rem;
    text-align: left;
}

.form-group {
    margin-bottom: 1.25rem;
    flex: 1;
}

.form-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 600;
    color: #cbd5e1;
    margin-bottom: 0.4rem;
}

.required {
    color: var(--error-color);
}

.form-row {
    display: flex;
    flex-direction: column;
    gap: 0;
}

@media (min-width: 640px) {
    .form-row {
        flex-direction: row;
        gap: 1rem;
    }
}

.form-input {
    width: 100%;
    padding: 0.75rem 1rem;
    border-radius: var(--radius);
    border: 1px solid var(--input-border);
    background-color: var(--input-bg);
    color: var(--text-color);
    font-size: 1rem;
    font-family: 'Inter', sans-serif;
    transition: border-color 0.3s ease;
}

.form-input:focus {
    outline: none;
    border-color: var(--primary-color);
}

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

.field-error {
    color: var(--error-color);
    font-size: 0.8rem;
    margin-top: 0.3rem;
    display: block;
}

.submit-btn {
    width: 100%;
    padding: 0.85rem 1.5rem;
    border-radius: var(--radius);
    border: none;
    background-color: var(--primary-color);
    color: white;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.15s ease;
    margin-top: 0.5rem;
}

.submit-btn:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
}

.submit-btn:active {
    transform: translateY(0);
}

.flash-messages {
    margin-bottom: 2rem;
}

.flash {
    padding: 1rem;
    border-radius: var(--radius);
    margin-bottom: 0.5rem;
    text-align: left;
    font-weight: 500;
}

.flash.success {
    background-color: rgba(16, 185, 129, 0.2);
    border: 1px solid var(--success-color);
    color: #6ee7b7;
}

.flash.error {
    background-color: rgba(239, 68, 68, 0.2);
    border: 1px solid var(--error-color);
    color: #fca5a5;
}

.flash.warning {
    background-color: rgba(245, 158, 11, 0.2);
    border: 1px solid var(--warning-color);
    color: #fcd34d;
}

footer {
    margin-top: 3rem;
    font-size: 0.875rem;
    color: #94a3b8;
}