body {
    font-family: 'Poppins', sans-serif;
    background-color: #f0f2f5;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    padding: 20px;
    box-sizing: border-box;
}
/* Input field when invalid */
.is-invalid {
  border: 2px solid #e63946;   /* red border */
  background-color: #fff5f5;   /* very light red background */
  outline: none;
  transition: 0.2s;
}

/* Error message text */
.invalid-feedback {
  color: #e63946;             /* red text */
  font-size: 0.9rem;
  margin-top: 4px;
  display: block;
}

.form-container {
    background-color: #ffffff;
    border-radius: 12px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 850px;
    padding: 40px;
    box-sizing: border-box;
}
/* ---------- Header ---------- */
.header {
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: left;
    margin-bottom: 30px;
    gap: 20px;
}
.header img {
    max-width: 100px;
    height: auto;
}
.header-text {
    display: flex;
    flex-direction: column;
    text-align: center;
}
.header h1 {
    color: #2c3e50;
    font-size: 1.8em;
    margin: 0;
    font-weight: 700;
}
.header h2 {
    color: #34495e;
    font-size: 1.2em;
    margin: 0;
    font-weight: 500;
}
@media (max-width: 768px) {
    .header { flex-direction: column; text-align: center; gap: 10px; }
}

/* ---------- Section Title ---------- */
.form-section-title {
    background-color: #34495e;
    color: #ffffff;
    padding: 12px 20px;
    margin: 30px -40px 30px -40px;
    font-size: 1.3em;
    font-weight: 600;
    text-align: center;
    border-top: 1px solid rgba(255,255,255,0.1);
    border-bottom: 1px solid rgba(0,0,0,0.1);
}

/* ---------- Important Instructions ---------- */
.important-instructions {
    background-color: #f8f9fa;
    border-left: 5px solid #007bff;
    padding: 20px 25px;
    margin-bottom: 30px;
    border-radius: 8px;
    box-shadow: inset 0 1px 3px rgba(0,0,0,0.05);
}
.important-instructions h4 {
    color: #007bff;
    margin-top: 0;
    margin-bottom: 10px;
    font-weight: 600;
    font-size: 1.1em;
}
.important-instructions ol {
    margin: 0;
    padding-left: 25px;
    color: #444;
    line-height: 1.6;
}

/* ---------- Form Grid ---------- */
.form-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 25px;
    margin-bottom: 30px;
}
.form-group {
    margin-bottom: 0;
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
}
.form-group.full-width {
    grid-column: 1 / -1;
}
.form-group label {
    display: block;
    margin-bottom: 8px;
    color: #333;
    font-weight: 500;
    font-size: 0.95em;
}

/* ---------- Input Fields ---------- */
.form-group input[type="number"],
.form-group input[type="text"],
.form-group input[type="date"],
.form-group input[type="email"] {
    width: 100%;
    padding: 12px 15px;
    border: 1px solid #dce0e5;
    border-radius: 8px;
    font-size: 1em;
    color: #333;
    background: #fafafa;
    transition: border-color 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
    box-sizing: border-box;
}
.form-group input:focus {
    background: #fff;
    border-color: #007bff;
    box-shadow: 0 0 0 3px rgba(0,123,255,0.25);
    outline: none;
}

/* ---------- Radio Buttons (Gender) ---------- */
.gender-group label {
    font-weight: 600;
    color: #2c3e50;
}
.radio-group {
    display: flex;
    gap: 25px;
    margin-top: 10px;
}
.radio-item {
    position: relative;
    padding: 8px 18px 8px 38px;
    background: #f8f9fa;
    border: 1px solid #dcdfe3;
    border-radius: 25px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 500;
    margin-right: 8px;
}
.radio-item:hover {
    background: #e9f2fc;
    border-color: #007bff;
}
.radio-item input[type="radio"] {
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    width: 18px;
    height: 18px;
    appearance: none;
    border: 2px solid #007bff;
    border-radius: 50%;
    outline: none;
    cursor: pointer;
    transition: 0.3s;
}
.radio-item input[type="radio"]:checked {
    background-color: #007bff;
    border-color: #007bff;
}
.radio-item input[type="radio"]:checked::before {
    content: '';
    position: absolute;
    left: 7px;
    top: 50%;
    transform: translate(-50%, -50%);
    width: 8px;
    height: 8px;
    background: #fff;
    border-radius: 50%;
}

/* ---------- Info & Buttons ---------- */
.organizer-info, .supervisor-info {
    text-align: center;
    margin-top: 40px;
    color: #555;
    font-size: 0.9em;
    line-height: 1.5;
}
.organizer-info strong, .supervisor-info strong {
    color: #2c3e50;
    font-size: 1.1em;
    font-weight: 600;
}
.button-group {
    text-align: center;
    margin-top: 40px;
}
.submit-button {
    background-color: #28a745;
    color: white;
    padding: 15px 30px;
    border: none;
    border-radius: 8px;
    font-size: 1.1em;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.2s ease;
    box-shadow: 0 4px 10px rgba(40, 167, 69, 0.2);
}
.submit-button:hover {
    background-color: #218838;
    transform: translateY(-2px);
}
.tex-box-super{
    display: flex;
    justify-content: space-between;
}
@media (max-width: 600px) {
    .submit-button { width: 100%; }
}
@media (max-width: 600px) {
    .form-grid {
        grid-template-columns: 1fr !important;
        gap: 16px !important;
    }
    .form-group,
    .form-group.full-width,
    .gender-group {
        width: 100% !important;
        margin-bottom: 0 !important;
    }
    .tex-box-super {
        flex-direction: column !important;
        gap: 12px !important;
        align-items: center !important;
        text-align: center !important;
    }
    .organizer-info, .supervisor-info {
        margin-top: 0 !important;
    }
}