/* shared.css - Global Styles for Advanced Web Solutions */

/* --- 1. CSS Variables for Theming --- */
:root {
    --primary-color: #007bff; /* Blue */
    --primary-dark: #0056b3;
    --primary-light: #e6f2ff;
    --secondary-color: #6c757d; /* Gray */
    --secondary-dark: #5a6268;
    --accent-color: #28a745; /* Green */
    --accent-dark: #218838;
    --background-light: #f8f9fa; /* Light Gray */
    --background-dark: #343a40; /* Dark Gray */
    --text-color-dark: #333;
    --text-color-light: #f8f9fa;
    --border-color: #dee2e6;
    --font-family-primary: 'Montserrat', sans-serif;
    --font-family-secondary: 'Roboto', sans-serif;
    --font-size-base: 16px;
    --line-height-base: 1.6;
    --spacing-xs: 0.5rem; /* 8px */
    --spacing-sm: 1rem;   /* 16px */
    --spacing-md: 1.5rem; /* 24px */
    --spacing-lg: 2rem;   /* 32px */
    --spacing-xl: 3rem;   /* 48px */
    --header-height: 70px;
    --footer-height: auto;
    --container-max-width: 1200px;
    --box-shadow-light: 0 4px 8px rgba(0, 0, 0, 0.1);
    --box-shadow-medium: 0 8px 16px rgba(0, 0, 0, 0.15);
    --transition-speed: 0.3s ease-in-out;
}

/* --- 2. Base Styles & Resets --- */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-size: var(--font-size-base);
}

body {
    font-family: var(--font-family-secondary);
    line-height: var(--line-height-base);
    color: var(--text-color-dark);
    background-color: var(--background-light);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

main {
    flex: 1;
    padding: var(--spacing-lg) 0;
}

/* --- 3. Typography --- */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-family-primary);
    margin-bottom: var(--spacing-sm);
    color: var(--primary-dark);
    line-height: 1.2;
}

h1 { font-size: 2.8rem; }
h2 { font-size: 2.2rem; }
h3 { font-size: 1.8rem; }
h4 { font-size: 1.5rem; }
h5 { font-size: 1.2rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: var(--spacing-sm);
}

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

a:hover, a:focus {
    color: var(--primary-dark);
    text-decoration: underline;
}

ul, ol {
    margin-left: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
}

li {
    margin-bottom: var(--spacing-xs);
}

/* --- 4. Layout & Containers --- */
.container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
}

.section-padding {
    padding: var(--spacing-xl) 0;
}

.text-center { text-align: center; }
.text-left   { text-align: left;   }
.text-right  { text-align: right;  }

/* --- 5. Buttons --- */
.btn {
    display: inline-block;
    padding: 0.8rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    text-align: center;
    text-decoration: none;
    border-radius: 5px;
    cursor: pointer;
    transition: all var(--transition-speed);
    border: 2px solid transparent;
}

.btn-primary {
    background-color: var(--primary-color);
    color: var(--text-color-light);
    border-color: var(--primary-color);
}

.btn-primary:hover, .btn-primary:focus {
    background-color: var(--primary-dark);
    border-color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--box-shadow-light);
}

.btn-secondary {
    background-color: var(--secondary-color);
    color: var(--text-color-light);
    border-color: var(--secondary-color);
}

.btn-secondary:hover, .btn-secondary:focus {
    background-color: var(--secondary-dark);
    border-color: var(--secondary-dark);
    transform: translateY(-2px);
    box-shadow: var(--box-shadow-light);
}

.btn-outline-primary {
    background-color: transparent;
    color: var(--primary-color);
    border-color: var(--primary-color);
}

.btn-outline-primary:hover, .btn-outline-primary:focus {
    background-color: var(--primary-color);
    color: var(--text-color-light);
    transform: translateY(-2px);
    box-shadow: var(--box-shadow-light);
}

/* --- 6. Forms --- */
input[type="text"],
input[type="email"],
input[type="password"],
input[type="tel"],
textarea,
select {
    width: 100%;
    padding: 0.75rem 1rem;
    margin-bottom: var(--spacing-sm);
    border: 1px solid var(--border-color);
    border-radius: 5px;
    font-family: var(--font-family-secondary);
    font-size: 1rem;
    color: var(--text-color-dark);
    background-color: #fff;
    transition: border-color var(--transition-speed), box-shadow var(--transition-speed);
}

input[type="text"]:focus,
input[type="email"]:focus,
input[type="password"]:focus,
input[type="tel"]:focus,
textarea:focus,
select:focus {
    border-color: var(--primary-color);
    outline: none;
    box-shadow: 0 0 0 0.2rem rgba(0, 123, 255, 0.25);
}

textarea {
    min-height: 120px;
    resize: vertical;
}

.form-group {
    margin-bottom: var(--spacing-md);
}

label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: 600;
    color: var(--text-color-dark);
}

/* --- 7. Utility Classes --- */
.shadow-sm { box-shadow: var(--box-shadow-light); }
.shadow-md { box-shadow: var(--box-shadow-medium); }

.rounded { border-radius: 8px; }
.rounded-full { border-radius: 50%; }

.mb-sm { margin-bottom: var(--spacing-sm); }
.mt-sm { margin-top: var(--spacing-sm); }
.py-md { padding-top: var(--spacing-md); padding-bottom: var(--spacing-md); }
.px-md { padding-left: var(--spacing-md); padding-right: var(--spacing-md); }

/* --- 8. Responsive Design Base (adjustments in specific component CSS) --- */
@media (max-width: 768px) {
    h1 { font-size: 2.2rem; }
    h2 { font-size: 1.8rem; }
    h3 { font-size: 1.5rem; }
    .container {
        padding: 0 var(--spacing-xs);
    }
}

@media (max-width: 480px) {
    h1 { font-size: 1.8rem; }
    h2 { font-size: 1.5rem; }
    h3 { font-size: 1.3rem; }
    .btn {
        padding: 0.7rem 1.2rem;
        font-size: 0.9rem;
    }
}
/* 移动端内容区防溢出（系统追加，请勿删除） */
@media (max-width: 768px) {
  .page-content img {
    max-width: 100% !important;
    height: auto !important;
    display: block;
  }
  .page-content {
    overflow-x: hidden;
    max-width: 100%;
  }
  body {
    overflow-x: hidden;
  }
}