:root {
    --primary-color: #4f46e5; /* Indigo 600 */
    --primary-hover: #4338ca; /* Indigo 700 */
    --bg-color: #f3f4f6; /* Gray 100 */
    --card-bg: #ffffff;
    --text-main: #1f2937; /* Gray 800 */
    --text-muted: #6b7280; /* Gray 500 */
    --border-radius: 12px;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

body {
    background-color: var(--bg-color);
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    color: var(--text-main);
    padding-bottom: 40px;
}

/* Header */
.app-header {
    background: linear-gradient(135deg, #4f46e5 0%, #6366f1 100%);
    color: white;
    padding: 40px 0;
    margin-bottom: -40px;
    padding-bottom: 80px;
}

.app-title {
    font-weight: 700;
    margin: 0;
    letter-spacing: -0.5px;
}

.app-subtitle {
    opacity: 0.9;
    font-weight: 300;
    margin-top: 5px;
}

/* Main Container */
.main-container {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Cards */
.custom-card {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    border: none;
    margin-bottom: 24px;
    overflow: hidden;
}

.card-header-custom {
    background: transparent;
    border-bottom: 1px solid #e5e7eb;
    padding: 20px 24px;
    font-weight: 600;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.1rem;
}

.card-body-custom {
    padding: 24px;
}

/* Smart Paste Section */
.smart-paste-card {
    border: 2px solid #e0e7ff;
    transition: all 0.3s ease;
}

.smart-paste-card:focus-within {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(79, 70, 229, 0.1);
}

.smart-btn {
    background-color: var(--primary-color);
    border: none;
    padding: 12px;
    font-weight: 500;
    transition: all 0.2s;
}

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

/* Form Controls */
.form-label {
    font-weight: 500;
    font-size: 0.95rem;
    color: #374151;
}

.form-control {
    border-radius: 8px;
    border: 1px solid #d1d5db;
    padding: 10px 14px;
    font-size: 0.95rem;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.form-control:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(79, 70, 229, 0.1);
}

.input-group-text {
    background-color: #f9fafb;
    border-color: #d1d5db;
    color: #6b7280;
}

.form-text {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-top: 6px;
}

/* Section Icons */
.bi {
    font-size: 1.2rem;
}

/* Submit Button */
.btn-submit {
    background: linear-gradient(135deg, #4f46e5 0%, #4338ca 100%);
    border: none;
    padding: 14px;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(79, 70, 229, 0.2);
    transition: all 0.3s;
}

.btn-submit:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 12px rgba(79, 70, 229, 0.3);
}

/* Footer */
.app-footer {
    text-align: center;
    color: #9ca3af;
    margin-top: 40px;
    font-size: 0.9rem;
}