:root {
    /* Color Palette - Professional Light & Glass */
    --primary: #2563eb;          /* Royal Blue */
    --primary-light: #3b82f6;    /* Bright Blue */
    --primary-glow: rgba(59, 130, 246, 0.3);
    --secondary: #059669;        /* Emerald Green (Success) */
    
    --bg-main: #f1f5f9;          /* Slate 100 - Light gray */
    --glass-bg: rgba(255, 255, 255, 0.7);
    --glass-border: rgba(255, 255, 255, 0.8);
    
    --text-main: #0f172a;        /* Slate 900 - Dark Text */
    --text-muted: #475569;       /* Slate 600 */
    
    --input-bg: rgba(255, 255, 255, 0.9);
    --zalo-color: #0068ff;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-main);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    overflow-x: hidden;
}

/* --- Main Layout --- */
.container {
    width: 100%;
    max-width: 600px;
    padding: 2rem;
    z-index: 10;
}

/* Header */
.form-header {
    text-align: center;
    margin-bottom: 2rem;
    animation: fadeDown 1s ease-out;
}
.glow-text {
    font-size: 2.2rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, #0f172a, var(--primary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}
.form-header p {
    color: var(--text-muted);
}

/* --- Glassmorphism Form --- */
.glass-form {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: 1.5rem;
    padding: 2rem;
    box-shadow: 0 20px 40px -15px rgba(0, 0, 0, 0.1);
    animation: fadeUp 1s ease-out;
}

.form-group {
    margin-bottom: 1.5rem;
}
.grid-2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
}

@media (max-width: 600px) {
    .grid-2 {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    .glass-form {
        padding: 1.5rem;
    }
}

/* Floating Input Aesthetics */
.input-wrapper {
    position: relative;
    display: flex;
    flex-direction: column-reverse;
}
.input-wrapper input,
.input-wrapper textarea {
    width: 100%;
    background: var(--input-bg);
    border: 1px solid rgba(0,0,0,0.1);
    color: var(--text-main);
    padding: 1rem 1.2rem;
    border-radius: 0.75rem;
    font-size: 1rem;
    transition: all 0.3s ease;
    outline: none;
    resize: none;
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.02);
}
.input-wrapper input:focus,
.input-wrapper textarea:focus {
    border-color: var(--primary-light);
    box-shadow: 0 0 0 4px var(--primary-glow);
    background: #ffffff;
}

.input-wrapper label {
    position: absolute;
    top: 50%;
    left: 1.2rem;
    transform: translateY(-50%);
    color: var(--text-muted);
    pointer-events: none;
    transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    background-color: transparent; /* Changed from dark */
    padding: 0 0.25rem;
    border-radius: 4px;
}
textarea ~ label {
    top: 1rem;
    transform: none;
}

/* Magic: Float Label on Focus or when not empty */
.input-wrapper input:focus ~ label,
.input-wrapper input:not(:placeholder-shown) ~ label,
.input-wrapper textarea:focus ~ label,
.input-wrapper textarea:not(:placeholder-shown) ~ label {
    top: 0;
    transform: translateY(-50%) scale(0.85);
    color: var(--primary);
    background-color: #ffffff;
    font-weight: 600;
}

/* Select Field */
.select-wrapper {
    flex-direction: column; 
}
select {
    width: 100%;
    background: var(--input-bg);
    border: 1px solid rgba(0,0,0,0.1);
    color: var(--text-main);
    padding: 1rem 1.2rem;
    border-radius: 0.75rem;
    font-size: 1rem;
    outline: none;
    appearance: none; 
    cursor: pointer;
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.02);
    /* Darker arrow for light theme */
    background-image: url("data:image/svg+xml;charset=US-ASCII,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%22292.4%22%20height%3D%22292.4%22%3E%3Cpath%20fill%3D%22%23475569%22%20d%3D%22M287%2069.4a17.6%2017.6%200%200%200-13-5.4H18.4c-5%200-9.3%201.8-12.9%205.4A17.6%2017.6%200%200%200%200%2082.2c0%205%201.8%209.3%205.4%2012.9l128%20127.9c3.6%203.6%207.8%205.4%2012.8%205.4s9.2-1.8%2012.8-5.4L287%2095c3.5-3.5%205.4-7.8%205.4-12.8%200-5-1.9-9.2-5.5-12.8z%22%2F%3E%3C%2Fsvg%3E");
    background-repeat: no-repeat;
    background-position: right 1.2rem top 50%;
    background-size: 0.65rem auto;
}
select:focus {
    border-color: var(--primary-light);
    box-shadow: 0 0 0 4px var(--primary-glow);
    background-color: #ffffff;
}
select option {
    background-color: #ffffff;
    color: var(--text-main);
}

/* File Upload Area */
.upload-area {
    position: relative;
    border: 2px dashed rgba(37, 99, 235, 0.4);
    border-radius: 0.75rem;
    padding: 2rem 1rem;
    text-align: center;
    cursor: pointer;
    background: rgba(37, 99, 235, 0.03);
    transition: all 0.3s ease;
}
.upload-area:hover, .upload-area.dragover {
    background: rgba(37, 99, 235, 0.08);
    border-color: var(--primary);
}
.upload-area input[type="file"] {
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
    opacity: 0;
    cursor: pointer;
}
.upload-icon {
    width: 48px;
    height: 48px;
    color: var(--primary);
    margin-bottom: 0.5rem;
}
#fileNameDisplay {
    display: block;
    font-weight: 600;
    color: var(--text-main);
    margin-bottom: 0.25rem;
}
.file-hint {
    display: block;
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* Submit Button */
.submit-btn {
    width: 100%;
    padding: 1.1rem;
    background: linear-gradient(to right, var(--primary), var(--primary-light));
    color: white;
    font-size: 1.1rem;
    font-weight: 700;
    border: none;
    border-radius: 0.75rem;
    cursor: pointer;
    position: relative;
    overflow: hidden;
    transition: transform 0.2s, box-shadow 0.2s;
    box-shadow: 0 4px 15px rgba(37, 99, 235, 0.3);
    display: flex;
    justify-content: center;
    align-items: center;
}
.submit-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(37, 99, 235, 0.4);
}
.submit-btn:active {
    transform: translateY(0);
}
.submit-btn:disabled {
    opacity: 0.7;
    cursor: not-allowed;
    transform: none;
}

/* Loader */
.loader {
    width: 24px;
    height: 24px;
    border: 3px solid rgba(255,255,255,0.3);
    border-top: 3px solid white;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    position: absolute;
}
.hidden { display: none !important; }
@keyframes spin { 0% { transform: rotate(0deg); } 100% { transform: rotate(360deg); } }

/* Feedback Messages */
.form-feedback {
    text-align: center;
    margin-top: 1rem;
    font-weight: 500;
    font-size: 0.95rem;
    opacity: 0;
    transition: opacity 0.3s;
}
.form-feedback.success {
    color: var(--secondary);
    opacity: 1;
}
.form-feedback.error {
    color: #dc2626; /* Deep Red */
    opacity: 1;
}

/* --- Zalo Float --- */
.zalo-float {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 60px;
    height: 60px;
    background-color: white;
    border-radius: 50%;
    box-shadow: 0 10px 25px rgba(0, 104, 255, 0.3);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 100;
    text-decoration: none;
    animation: pulse 2s infinite;
    transition: transform 0.3s;
    opacity: 0;
}
.zalo-float img {
    width: 35px;
    height: 35px;
}
.zalo-float:hover {
    transform: scale(1.1);
}
.zalo-tooltip {
    position: absolute;
    right: 75px;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(8px);
    padding: 0.5rem 1rem;
    border-radius: 1rem;
    color: var(--text-main);
    font-weight: 500;
    font-size: 0.85rem;
    white-space: nowrap;
    opacity: 0;
    pointer-events: none;
    transition: 0.3s;
    box-shadow: 0 4px 10px rgba(0,0,0,0.05);
}
.zalo-float:hover .zalo-tooltip {
    opacity: 1;
}

@keyframes pulse {
    0% { box-shadow: 0 0 0 0 rgba(0, 104, 255, 0.4); }
    70% { box-shadow: 0 0 0 15px rgba(0, 104, 255, 0); }
    100% { box-shadow: 0 0 0 0 rgba(0, 104, 255, 0); }
}

@keyframes fadeDown {
    from { opacity: 0; transform: translateY(-20px); }
    to { opacity: 1; transform: translateY(0); }
}
@keyframes fadeUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}