/**
 * ==========================================================
 * Strayglow of Saga - Auth Login Styles (Modern)
 * ==========================================================
 *
 * LAMP共通デザイン準拠
 * タイトルテキスト: IMPACT フォント使用
 *
 * 統一ブレークポイント（breakpoints.css 参照）:
 * - xs: 360px  (小型スマートフォン)
 * - sm: 480px  (スマートフォン)
 * - md: 768px  (タブレット)
 * - lg: 960px  (デスクトップ)
 * - xl: 1200px (大画面)
 *
 * ==========================================================
 */

:root {
  /* ========== Base Tokens（LAMP共通） ========== */
  --color-border: 186, 202, 226;
  --color-shadow: 6, 10, 16;
  --color-bg-dark: 24, 28, 36;
  --color-bg-medium: 44, 58, 78;
  --color-bg-light: 72, 92, 118;
  --color-success: 155, 226, 155;
  --success-text: #d8f0df;
  --color-warning: 239, 197, 103;
  --warning-text: #f5d197;
  --color-error: 239, 68, 68;
  --error-text: #fca5a5;
  --color-accent: 107, 220, 255;

  /* ========== Semantic Tokens（LAMP共通） ========== */
  --card-bg: rgba(var(--color-bg-dark), 0.78);
  --panel-bg: rgba(var(--color-bg-medium), 0.22);
  --panel-bg-alt: rgba(var(--color-bg-medium), 0.28);
  --panel-bg-hover: rgba(var(--color-bg-light), 0.36);
  --border-subtle: rgba(var(--color-border), 0.18);
  --border-default: rgba(var(--color-border), 0.28);
  --border-strong: rgba(var(--color-border), 0.32);
  --success-bg: rgba(var(--color-success), 0.22);
  --success-border: rgba(var(--color-success), 0.45);
  --warning-bg: rgba(var(--color-warning), 0.16);
  --warning-border: rgba(var(--color-warning), 0.45);
  --warning-glow: rgba(var(--color-warning), 0.35);
  --error-bg: rgba(var(--color-error), 0.18);
  --error-border: rgba(var(--color-error), 0.45);
  --accent-bg: rgba(var(--color-accent), 0.15);
  --accent-border: rgba(var(--color-accent), 0.4);
  --accent-glow: rgba(var(--color-accent), 0.3);

  /* ========== Login Page Specific ========== */
  --fg: #f3f6fb;
  --fg-soft: #c9d3e2;
  --fg-muted: #9aa7bb;
  --gap: clamp(10px, 1.6vw, 18px);
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-pill: 999px;
  --blur: 12px;
  --t: 0.35s;
  --ease: cubic-bezier(0.25, 0.8, 0.25, 1);
  --text-sm: 0.88rem;
  --text-xs: 0.82rem;

  /* ========== Shadow Tokens（LAMP共通） ========== */
  --shadow-sm: 0 6px 14px rgba(var(--color-shadow), 0.24);
  --shadow-md: 0 10px 20px rgba(var(--color-shadow), 0.28);
  --shadow-lg: 0 16px 36px rgba(var(--color-shadow), 0.32);
}

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

html,
body {
  min-height: 100%;
  margin: 0;
}

body {
  color: var(--fg);
  font-family: "Segoe UI", "Noto Sans JP", system-ui, sans-serif;
  background:
    radial-gradient(120% 120% at 28% 0%, rgba(var(--color-accent), 0.16), transparent 46%),
    radial-gradient(95% 95% at 80% 0%, rgba(var(--color-warning), 0.12), transparent 40%),
    linear-gradient(180deg, #1c2430, #0e131a);
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: clamp(16px, 4vw, 32px);
  letter-spacing: 0.02em;
  overflow-x: hidden;
}

/* ========== Background Effects ========== */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 50% at 50% -20%, rgba(var(--color-accent), 0.15), transparent),
    radial-gradient(ellipse 60% 40% at 100% 50%, rgba(var(--color-warning), 0.08), transparent),
    radial-gradient(ellipse 60% 40% at 0% 50%, rgba(var(--color-accent), 0.06), transparent);
  pointer-events: none;
  z-index: -1;
}

/* ========== Main Stage ========== */
.auth-stage {
  position: relative;
  width: 100%;
  max-width: 420px;
  animation: fadeSlideUp 0.6s var(--ease) forwards;
}

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

/* Decorative background elements - hidden on mobile */
.stage-bg,
.stage-drape {
  display: none;
}

/* ========== Card ========== */
.auth-card {
  background: var(--card-bg);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
  padding: clamp(28px, 6vw, 40px);
  box-shadow:
    var(--shadow-lg),
    inset 0 1px 0 rgba(255, 255, 255, 0.05);
  backdrop-filter: blur(var(--blur));
  display: flex;
  flex-direction: column;
  gap: clamp(24px, 4vw, 32px);
}

/* ========== Card Header ========== */
.auth-card__header {
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.auth-card__title {
  margin: 0;
  font-size: 2rem;
  font-weight: 400;
  letter-spacing: 0.08em;
  font-family: Impact, "Arial Black", "Hiragino Kaku Gothic ProN", "Noto Sans JP", system-ui, sans-serif;
  text-transform: uppercase;
  background: linear-gradient(
    135deg,
    var(--fg) 0%,
    rgba(var(--color-accent), 1) 50%,
    var(--fg) 100%
  );
  background-size: 200% 200%;
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;

  text-shadow: none;
  filter: drop-shadow(0 2px 8px rgba(var(--color-accent), 0.3));
}

@keyframes shimmer {
  0%, 100% {
    background-position: 0% 50%;
  }
  50% {
    background-position: 100% 50%;
  }
}

.auth-card__subtitle {
  margin: 0;
  color: var(--fg-muted);
  font-size: var(--text-sm);
  font-weight: 400;
}

/* ========== Form ========== */
.auth-form {
  display: flex;
  flex-direction: column;
  gap: clamp(16px, 3vw, 20px);
}

/* ========== Field ========== */
.auth-field {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.auth-field label {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--fg-soft);
  letter-spacing: 0.04em;
}

/* ========== Input ========== */
.auth-input {
  appearance: none;
  width: 100%;
  padding: 14px 16px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-subtle);
  background: var(--panel-bg);
  color: var(--fg);
  font-size: 1rem;
  letter-spacing: 0.02em;
  transition:
    border-color var(--t) var(--ease),
    box-shadow var(--t) var(--ease),
    background var(--t) var(--ease);
}

.auth-input::placeholder {
  color: var(--fg-muted);
  opacity: 0.7;
}

.auth-input:hover {
  border-color: var(--border-default);
  background: var(--panel-bg-alt);
}

.auth-input:focus {
  outline: none;
  border-color: rgba(var(--color-accent), 0.5);
  box-shadow:
    0 0 0 3px var(--accent-glow),
    0 0 20px rgba(var(--color-accent), 0.1);
  background: var(--panel-bg-hover);
}

/* ========== Submit Button ========== */
.auth-submit {
  appearance: none;
  position: relative;
  width: 100%;
  padding: 16px 24px;
  margin-top: 8px;
  border: 1px solid var(--accent-border);
  border-radius: var(--radius-pill);
  background: linear-gradient(
    135deg,
    rgba(var(--color-accent), 0.2) 0%,
    rgba(var(--color-accent), 0.1) 100%
  );
  color: var(--fg);
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  cursor: pointer;
  transition:
    transform var(--t) var(--ease),
    box-shadow var(--t) var(--ease),
    background var(--t) var(--ease);
  overflow: hidden;
}

.auth-submit::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(
    135deg,
    rgba(var(--color-accent), 0.3) 0%,
    rgba(var(--color-accent), 0.1) 100%
  );
  opacity: 0;
  transition: opacity var(--t) var(--ease);
}

.auth-submit:hover {
  transform: translateY(-2px);
  box-shadow:
    0 8px 24px rgba(var(--color-accent), 0.25),
    0 0 40px rgba(var(--color-accent), 0.1);
}

.auth-submit:hover::before {
  opacity: 1;
}

.auth-submit:active {
  transform: translateY(0);
}

.auth-submit:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

/* ========== Signup Link ========== */
.auth-signup {
  margin: 0;
  text-align: center;
  font-size: var(--text-sm);
  color: var(--fg-muted);
}

.auth-signup a {
  color: rgba(var(--color-accent), 1);
  text-decoration: none;
  font-weight: 600;
  letter-spacing: 0.04em;
  transition: color var(--t) var(--ease);
}

.auth-signup a:hover {
  color: var(--fg);
  text-decoration: underline;
}

/* ========== Footer (Error Message) ========== */
.auth-footer {
  margin: 0;
  padding: 12px 16px;
  text-align: center;
  font-size: var(--text-sm);
  color: var(--error-text);
  background: var(--error-bg);
  border: 1px solid var(--error-border);
  border-radius: var(--radius-md);
  animation: shake 0.5s var(--ease);
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  20%, 60% { transform: translateX(-4px); }
  40%, 80% { transform: translateX(4px); }
}

/* ========== Flash Messages ========== */
.flash-messages {
  position: static;
  width: 100%;
  max-width: 100%;
  margin-top: 16px;
}

.flash-message {
  padding: 12px 16px;
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  animation: slideDown 0.4s var(--ease);
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.flash-message--success {
  background: var(--success-bg);
  border: 1px solid var(--success-border);
  color: var(--success-text);
}

.flash-message--error {
  background: var(--error-bg);
  border: 1px solid var(--error-border);
  color: var(--error-text);
}

.flash-message--warning {
  background: var(--warning-bg);
  border: 1px solid var(--warning-border);
  color: var(--warning-text);
}

/* ========== Responsive: Tablet and up ========== */
@media (min-width: 768px) {
  .auth-stage {
    max-width: 460px;
  }

  .flash-messages {
    position: fixed;
    top: 16px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 1000;
    width: 90%;
    max-width: 400px;
    margin-top: 0;
  }

  .auth-card {
    padding: 48px;
  }

  .auth-card__title {
    font-size: 2.5rem;
  }
}

/* ========== Responsive: Desktop and up ========== */
@media (min-width: 960px) {
  .auth-stage {
    max-width: 480px;
  }

  .auth-card {
    border-radius: var(--radius-lg);
  }
}