:root {
    --tecfe-blue: #0055A4;
    --tecfe-blue-dark: #004080;
    --tecfe-blue-light: #1a75c4;
    --tecfe-green: #7ED321;
    --white: #ffffff;
    --gray-100: #f5f5f5;
    --gray-200: #e5e5e5;
    --gray-600: #666666;
    --gray-800: #333333;
    --danger: #dc3545;
    --warning: #ffc107;
    --success: #28a745;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--gray-100);
    color: var(--gray-800);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

/* Screen management */
.screen {
    min-height: 100vh;
}

.hidden {
    display: none !important;
}

/* Login Screen */
#login-screen {
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--tecfe-blue) 0%, var(--tecfe-blue-dark) 100%);
    padding: 20px;
}

.login-container {
    background: var(--white);
    border-radius: 16px;
    padding: 40px 30px;
    width: 100%;
    max-width: 400px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

.logo {
    text-align: center;
    margin-bottom: 30px;
}

.logo h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--tecfe-blue);
    letter-spacing: -1px;
}

.logo p {
    font-size: 0.85rem;
    color: var(--tecfe-green);
    margin-top: 5px;
    font-weight: 500;
}

#login-form {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

#login-form input {
    padding: 14px 16px;
    border: 2px solid var(--gray-200);
    border-radius: 10px;
    font-size: 16px;
    transition: border-color 0.2s;
}

#login-form input:focus {
    outline: none;
    border-color: var(--tecfe-blue);
}

#login-form button {
    background: var(--tecfe-blue);
    color: var(--white);
    border: none;
    padding: 16px;
    border-radius: 10px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
}

#login-form button:hover {
    background: var(--tecfe-blue-dark);
}

.error {
    color: var(--danger);
    font-size: 14px;
    text-align: center;
    margin-top: 10px;
}

/* App Screen */
#app-screen {
    background: var(--gray-100);
}

header {
    background: var(--tecfe-blue);
    color: var(--white);
    padding: 15px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.logo-small {
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: -0.5px;
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.2);
    color: var(--white);
    border: none;
    padding: 8px 16px;
    border-radius: 8px;
    font-size: 14px;
    cursor: pointer;
    transition: background 0.2s;
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.3);
}

/* Main content */
main {
    padding: 20px;
    max-width: 800px;
    margin: 0 auto;
}

/* Cards */
.card {
    background: var(--white);
    border-radius: 12px;
    padding: 20px;
    margin-bottom: 20px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

.card h2 {
    color: var(--tecfe-blue);
    font-size: 1.2rem;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--gray-200);
}

.card h3 {
    color: var(--gray-800);
    font-size: 1rem;
    margin: 20px 0 15px;
    padding: 10px;
    background: var(--gray-100);
    border-radius: 8px;
    border-left: 4px solid var(--tecfe-green);
}

/* Form groups */
.form-group {
    margin-bottom: 15px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: 500;
    color: var(--gray-600);
    font-size: 14px;
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--gray-200);
    border-radius: 8px;
    font-size: 16px;
    transition: border-color 0.2s;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--tecfe-blue);
}

/* Row layout for temperature fields */
.row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

/* Equipment sections */
.equipo-section {
    background: var(--gray-100);
    border-radius: 10px;
    padding: 15px;
    margin-bottom: 15px;
}

/* Submit button */
.btn-submit {
    background: var(--tecfe-green);
    color: var(--white);
    border: none;
    padding: 18px;
    border-radius: 12px;
    font-size: 18px;
    font-weight: 600;
    width: 100%;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
    margin-top: 20px;
}

.btn-submit:hover {
    background: #6bc01a;
}

.btn-submit:active {
    transform: scale(0.98);
}

/* Success message */
.success {
    background: var(--success);
    color: var(--white);
    padding: 15px;
    border-radius: 10px;
    text-align: center;
    margin-top: 20px;
    font-weight: 500;
}

/* Responsive */
@media (max-width: 480px) {
    .row {
        grid-template-columns: 1fr;
    }
    
    .login-container {
        padding: 30px 20px;
    }
    
    .logo h1 {
        font-size: 2rem;
    }
    
    main {
        padding: 15px;
    }
}