/* General Styles */
:root {
    --primary-color: #3498db;
    --secondary-color: #2c3e50;
    --accent-color: #e74c3c;
    --light-bg: #f4f7f6;
    --dark-text: #333;
    --light-text: #ecf0f1;
    --border-color: #ddd;
    --shadow-light: 0 2px 10px rgba(0, 0, 0, 0.08);
    --shadow-medium: 0 4px 20px rgba(0, 0, 0, 0.1);
}

body {
    font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--light-bg);
    margin: 0;
    padding: 0;
    color: var(--dark-text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 40px auto;
    padding: 30px;
    background-color: #fff;
    border-radius: 10px;
    box-shadow: var(--shadow-medium);
}

.narrow-container { /* For forms like login and registration */
    width: 90%;
    max-width: 500px;
    margin: 60px auto;
    padding: 40px;
    background-color: #fff;
    border-radius: 10px;
    box-shadow: var(--shadow-medium);
    text-align: center;
}

h1, h2, h3, h4, h5, h6 {
    color: var(--secondary-color);
    margin-bottom: 20px;
    font-weight: 600;
}

h1 {
    font-size: 2.8em;
    text-align: center;
    color: var(--primary-color);
    margin-bottom: 30px;
}

h2 {
    font-size: 2.2em;
    color: var(--primary-color);
    padding-bottom: 10px;
    margin-bottom: 25px;
    
}

h3 {
    font-size: 1.8em;
    color: var(--dark-text);
    margin-bottom: 15px;
}

/* Forms */
form {
    margin-top: 20px;
}

label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--dark-text);
    text-align: left;
}

input[type="text"],
input[type="email"],
input[type="password"],
input[type="date"],
input[type="datetime-local"],
input[type="tel"] { /* Changed from phone to tel for semantic HTML */
    width: 100%;
    padding: 12px 15px;
    margin-bottom: 20px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 1em;
    box-sizing: border-box;
    transition: border-color 0.2s ease-in-out, box-shadow 0.2s ease-in-out;
}

input[type="text"]:focus,
input[type="email"]:focus,
input[type="password"]:focus,
input[type="date"]:focus,
input[type="datetime-local"]:focus,
input[type="tel"]:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
    outline: none;
}

button[type="submit"], .button, .admin-button {
    display: inline-block;
    padding: 12px 25px;
    background-color: var(--primary-color);
    color: white;
    font-size: 1.1em;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    text-decoration: none;
    transition: background-color 0.3s ease, transform 0.2s ease;
    text-align: center;
}

button[type="submit"]:hover, .button:hover, .admin-button:hover {
    background-color: #2980b9;
    transform: translateY(-2px);
}

.button.alt {
    background-color: var(--secondary-color);
}
.button.alt:hover {
    background-color: #34495e;
}

.button.danger {
    background-color: var(--accent-color);
}
.button.danger:hover {
    background-color: #c0392b;
}

/* Header & Navigation */
.header {
    background-color: var(--secondary-color);
    color: var(--light-text);
    padding: 15px 0;
    box-shadow: var(--shadow-light);
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
}

.logo a {
    color: var(--light-text);
    font-size: 1.8em;
    font-weight: 700;
    text-decoration: none;
}

.nav ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
}

.nav ul li {
    margin-left: 25px;
}

.nav ul li a {
    color: var(--light-text);
    text-decoration: none;
    font-size: 1.1em;
    transition: color 0.3s ease;
}

.nav ul li a:hover {
    color: var(--primary-color);
}

.admin-link {
    background-color: var(--primary-color);
    color: white;
    padding: 8px 15px;
    border-radius: 5px;
    text-decoration: none;
    font-weight: 500;
    transition: background-color 0.3s ease;
}

.admin-link:hover {
    background-color: #2980b9;
}


/* Conference Details on Index */
.conference-details {
    background-color: var(--light-bg);
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 30px;
    box-shadow: var(--shadow-light);
    text-align: center;
}

.conference-details p {
    margin: 8px 0;
    font-size: 1.1em;
}
.conference-details strong {
    color: var(--primary-color);
}


/* Tables (Admin Pages) */
table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 25px;
    box-shadow: var(--shadow-light);
    border-radius: 8px;
    overflow: hidden; /* Ensures border-radius applies to table elements */
}

table th, table td {
    padding: 15px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

table th {
    background-color: var(--secondary-color);
    color: var(--light-text);
    font-weight: 600;
    text-transform: uppercase;
    font-size: 0.9em;
}

table tr:nth-child(even) {
    background-color: #f9f9f9;
}

table tr:hover {
    background-color: #f1f1f1;
}

table td a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.2s ease;
    margin-right: 10px;
}

table td a:hover {
    color: #2980b9;
    text-decoration: underline;
}

/* Alerts and Messages */
.message {
    padding: 15px;
    border-radius: 5px;
    margin-bottom: 20px;
    font-weight: 500;
}

.message.success {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.message.error {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

/* Footer */
footer {
    text-align: center;
    margin-top: 50px;
    padding: 20px;
    font-size: 0.9em;
    color: #7f8c8d;
    border-top: 1px solid var(--border-color);
    background-color: #fff;
}

footer a {
    color: var(--primary-color);
    text-decoration: none;
}

footer a:hover {
    text-decoration: underline;
}

/* Admin Dashboard Specific */
.admin-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

.admin-card {
    background-color: #fff;
    padding: 30px;
    border-radius: 10px;
    box-shadow: var(--shadow-light);
    text-align: center;
    transition: transform 0.2s ease-in-out, box-shadow 0.2s ease-in-out;
}

.admin-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 25px rgba(0, 0, 0, 0.12);
}

.admin-card h3 {
    font-size: 1.6em;
    margin-bottom: 20px;
    color: var(--primary-color);
}

.admin-card p {
    margin-bottom: 25px;
    color: #555;
}
.logo img.header-logo {
    max-height: 40px; /* Adjust as needed */
    width: auto;     /* Maintain aspect ratio */
    display: block;  /* Removes extra space below image */
}

/* If you want to remove the old text-based logo styling */
.logo a {
    /* Remove or comment out these lines if you no longer need text-based styling for the logo */
    /* color: var(--light-text);
    font-size: 1.8em;
    font-weight: 700;
    text-decoration: none; */
}

/* Adjust header padding if logo makes it too big/small */
.header {
    padding: 10px 0; /* Example: Reduce padding if the logo is smaller */
}

/* Adjust for smaller screens if necessary */
@media (max-width: 768px) {
    .logo img.header-logo {
        max-height: 35px; /* Slightly smaller logo on mobile */
    }
    .header {
        padding: 8px 0;
    }
}


/* Responsive Adjustments */
@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        text-align: center;
    }
    .nav ul {
        margin-top: 15px;
        flex-direction: column;
    }
    .nav ul li {
        margin: 5px 0;
    }
    .container, .narrow-container {
        margin: 20px auto;
        padding: 20px;
    }
    h1 {
        font-size: 2em;
    }
    h2 {
        font-size: 1.8em;
    }
    table th, table td {
        padding: 10px;
        font-size: 0.9em;
    }
}