/* ========================================
   税理士法人赤坂税務総合事務所
   Main Stylesheet
   ======================================== */

/* CSS Variables */
:root {
  /* Colors */
  --color-primary: #1a365d;
  --color-primary-light: #2b6cb0;
  --color-primary-accent: #3182ce;
  --color-secondary: #4299e1;
  --color-background: #f7fafc;
  --color-background-alt: #edf2f7;
  --color-text: #2d3748;
  --color-text-light: #4a5568;
  --color-text-muted: #718096;
  --color-white: #ffffff;
  --color-border: #e2e8f0;
  --color-success: #38a169;
  --color-error: #e53e3e;
  --color-warning: #d69e2e;
  
  /* Typography */
  --font-family: 'Hiragino Kaku Gothic ProN', 'Hiragino Sans', 'Yu Gothic', 'Meiryo', sans-serif;
  --font-size-base: 16px;
  --font-size-sm: 14px;
  --font-size-xs: 12px;
  --font-size-lg: 18px;
  --font-size-xl: 20px;
  --font-size-2xl: 24px;
  --font-size-3xl: 30px;
  --font-size-4xl: 36px;
  --font-size-5xl: 48px;
  
  /* Spacing */
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-2xl: 48px;
  --spacing-3xl: 64px;
  --spacing-4xl: 96px;
  
  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  
  /* Shadows */
  --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);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 300ms ease;
  --transition-slow: 500ms ease;
  
  /* Container */
  --container-max-width: 1200px;
  --container-padding: 20px;
}

/* ========================================
   Reset & Base Styles
   ======================================== */

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

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

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-background);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

main {
  flex: 1;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

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

a:hover {
  color: var(--color-primary-light);
}

ul, ol {
  list-style: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

input, textarea, select {
  font-family: inherit;
  font-size: inherit;
}

/* ========================================
   Typography
   ======================================== */

h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.3;
  color: var(--color-primary);
}

h1 {
  font-size: var(--font-size-4xl);
}

h2 {
  font-size: var(--font-size-3xl);
}

h3 {
  font-size: var(--font-size-2xl);
}

h4 {
  font-size: var(--font-size-xl);
}

h5 {
  font-size: var(--font-size-lg);
}

h6 {
  font-size: var(--font-size-base);
}

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

p:last-child {
  margin-bottom: 0;
}

/* ========================================
   Container
   ======================================== */

.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.container--narrow {
  max-width: 800px;
}

.container--wide {
  max-width: 1400px;
}

/* ========================================
   Sections
   ======================================== */

.section {
  padding: var(--spacing-3xl) 0;
}

.section--alt {
  background-color: var(--color-background-alt);
}

.section--primary {
  background-color: var(--color-primary);
  color: var(--color-white);
}

.section--primary h2,
.section--primary h3,
.section--primary h4 {
  color: var(--color-white);
}

.section__header {
  text-align: center;
  margin-bottom: var(--spacing-2xl);
}

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

.section__subtitle {
  font-size: var(--font-size-lg);
  color: var(--color-text-light);
  max-width: 600px;
  margin: 0 auto;
}

/* ========================================
   Buttons
   ======================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-xl);
  font-size: var(--font-size-base);
  font-weight: 600;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  text-align: center;
  white-space: nowrap;
}

.btn--primary {
  background-color: var(--color-primary-accent);
  color: var(--color-white);
}

.btn--primary:hover {
  background-color: var(--color-primary-light);
  color: var(--color-white);
}

.btn--secondary {
  background-color: var(--color-white);
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.btn--secondary:hover {
  background-color: var(--color-primary);
  color: var(--color-white);
}

.btn--large {
  padding: var(--spacing-lg) var(--spacing-2xl);
  font-size: var(--font-size-lg);
}

.btn--small {
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: var(--font-size-sm);
}

.btn--block {
  width: 100%;
}

/* ========================================
   Forms
   ======================================== */

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

.form-label {
  display: block;
  margin-bottom: var(--spacing-sm);
  font-weight: 600;
  color: var(--color-text);
}

.form-label--required::after {
  content: '（必須）';
  color: var(--color-error);
  font-size: var(--font-size-sm);
  margin-left: var(--spacing-xs);
}

.form-input,
.form-textarea,
.form-select {
  width: 100%;
  padding: var(--spacing-md);
  font-size: var(--font-size-base);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background-color: var(--color-white);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
  outline: none;
  border-color: var(--color-primary-accent);
  box-shadow: 0 0 0 3px rgba(49, 130, 206, 0.2);
}

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

.form-checkbox {
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-sm);
  cursor: pointer;
}

.form-checkbox input[type="checkbox"] {
  width: 20px;
  height: 20px;
  margin-top: 2px;
  cursor: pointer;
  accent-color: var(--color-primary-accent);
}

.form-checkbox-label {
  font-size: var(--font-size-sm);
  color: var(--color-text-light);
  line-height: 1.5;
}

.form-checkbox-label a {
  text-decoration: underline;
}

.form-error {
  color: var(--color-error);
  font-size: var(--font-size-sm);
  margin-top: var(--spacing-xs);
}

/* ========================================
   Cards
   ======================================== */

.card {
  background-color: var(--color-white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  overflow: hidden;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
}

.card__image {
  width: 100%;
  height: 200px;
  object-fit: cover;
}

.card__content {
  padding: var(--spacing-lg);
}

.card__title {
  font-size: var(--font-size-xl);
  margin-bottom: var(--spacing-sm);
}

.card__text {
  color: var(--color-text-light);
  font-size: var(--font-size-base);
}

/* ========================================
   Grid
   ======================================== */

.grid {
  display: grid;
  gap: var(--spacing-lg);
}

.grid--2 {
  grid-template-columns: repeat(2, 1fr);
}

.grid--3 {
  grid-template-columns: repeat(3, 1fr);
}

.grid--4 {
  grid-template-columns: repeat(4, 1fr);
}

/* ========================================
   Utilities
   ======================================== */

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

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

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

.text-primary {
  color: var(--color-primary);
}

.text-muted {
  color: var(--color-text-muted);
}

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }
.mb-4 { margin-bottom: var(--spacing-xl); }
.mb-5 { margin-bottom: var(--spacing-2xl); }

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mt-4 { margin-top: var(--spacing-xl); }
.mt-5 { margin-top: var(--spacing-2xl); }

.hidden {
  display: none !important;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ========================================
   Animations
   ======================================== */

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

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

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

.fade-in {
  animation: fadeIn var(--transition-base) ease-out;
}

.slide-up {
  animation: slideUp var(--transition-base) ease-out;
}

.slide-down {
  animation: slideDown var(--transition-base) ease-out;
}